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Review

Recent Developments in Coatings for Orthopedic Metallic Implants

by
Muzamil Hussain
1,†,
Syed Hasan Askari Rizvi
2,†,
Naseem Abbas
3,*,
Uzair Sajjad
4,
Muhammad Rizwan Shad
5,
Mohsin Ali Badshah
6,* and
Asif Iqbal Malik
7,*
1
Department of Mechanical Engineering, COMSATS University Islamabad, Sahiwal 57000, Pakistan
2
School of Mechanical Engineering, Chung-Ang University, Seoul 06974, Korea
3
Nano-Biofluignostic Research Center, Korea University, Seoul 02841, Korea
4
Department of Mechanical Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
5
Department of Mechanical Engineering, University of Central Punjab, Lahore 54000, Pakistan
6
Department of Chemical and Biomolecular Engineering, University of California-Irvine, Irvine, CA 92697, USA
7
Department of Hotel and Tourism Management, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul 05006, Korea
*
Authors to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Coatings 2021, 11(7), 791; https://doi.org/10.3390/coatings11070791
Submission received: 31 May 2021 / Revised: 22 June 2021 / Accepted: 28 June 2021 / Published: 30 June 2021
(This article belongs to the Special Issue Nanomaterial- and Nanostructure-Based Coatings: Fabrication, Characterization, and Applications)
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Versions Notes

Abstract

:
Titanium, stainless steel, and CoCrMo alloys are the most widely used biomaterials for orthopedic applications. The most common causes of orthopedic implant failure after implantation are infections, inflammatory response, least corrosion resistance, mismatch in elastic modulus, stress shielding, and excessive wear. To address the problems associated with implant materials, different modifications related to design, materials, and surface have been developed. Among the different methods, coating is an effective method to improve the performance of implant materials. In this article, a comprehensive review of recent studies has been carried out to summarize the impact of coating materials on metallic implants. The antibacterial characteristics, biodegradability, biocompatibility, corrosion behavior, and mechanical properties for performance evaluation are briefly summarized. Different effective coating techniques, coating materials, and additives have been summarized. The results are useful to produce the coating with optimized properties.

1. Introduction

Many materials including polymers, metals, alloys, ceramics, and composites are used in orthopedic applications [1,2,3,4,5]. These materials are required to have excellent physical, mechanical, and tribological properties and must be non-toxic, biocompatible, and corrosion-resistant [6,7]. The most widely used materials for orthopedic applications are listed in Table 1. The problems with these conventional materials are their least biodegradability, biological inertness, similarity in properties to the bone, long-term stability, wear, and corrosion resistance [8,9,10,11,12,13,14,15,16,17]. The other issues related to these implant materials are stress shielding, secondary infections, metal ion release, etc [18,19,20,21,22,23,24,25]. Therefore, in most cases, multiple revisions are required in case of failure of implants. Moreover, the implants made of non-degradable materials often remain in the body up to their need. Hence, the non-degradability and long healing time demand revision surgery to replace or remove the implant after healing [26,27,28,29].
The fabrication of coatings on implant materials has become a topic of major interest to enhance the biological, tribological, antibacterial, and mechanical properties of orthopedics. The most important objective of implant material is to improve biocompatibility. The coating of bioactive material improves biocompatibility, prevents ion release from the metallic substrate which results in reduced mechanical failure. A high-quality coating should exhibit sufficient adhesion strength (50 MPa approved by US-FDA), high hardness of the final coat, excellent osseointegration, and osteoconduction properties, reduced cracks among the coating, and free of inclusions [30]. Another important feature is the degree of crystallinity which affects the solubility of the bioactive coating in the human body [30]. This article aims to review the impacts of coatings on the implant materials for the orthopedic prosthesis. The relative comparison of different coatings on metallic implant materials is reviewed systematically to choose the optimized coating properties.

2. Coating Techniques

To enhance the efficacy of biomedical implants huge research has been carried out with a prime focus on developing techniques for coating or depositing bioactive materials on metallic substrates. Nowadays, researchers around the world are performing research on coating techniques to find the optimum processing parameters. There is further need for investigation on optimum adhesion between coating and substrate, development of methods for multilayers deposition to achieve different characteristics, and use of novel materials. The most common techniques that are recently used for coating metallic implant materials are listed in Table 2.
The physical vapor deposition (PVD) method includes different surface modifications such as evaporation, ion plating, and sputtering. The core idea behind these techniques is that a material is coated on a metal surface by initially vaporizing the material then letting it condense on a metal surface [41]. In orthopedics, sputtering is the most used method for coating metallic implant materials. Sputtering is usually carried out in the argon-rich environment in which gaseous argon is turned into positively charged vapors. These positively charged argon ions then collide with the metal substrate, generating reactive metal molecules. That bombard into metal and create a coating layer. In magnetron sputtering close magnetic field is used to control the ionization rate [42,43]. PVD is used to develop high purity and high dense bioactive coatings on implant materials with good adhesion strength. However, PVD is a time-consuming and expensive technique and produces a low crystalline layer that may be dissolved in the human body. Hence, further studies are needed to study the influence of PVD processing parameters on the crystallinity, porosity, and stability of bioactive coatings.
In the Chemical vapor deposition (CVD) technique, high temperature, high pressurized reactant gas is placed in a reactor which reacts with the metal surface to produce a thin coating on it [81,82]. CVD is capable to produce complex geometries, but a high initial cost is required for specialized equipment. Furthermore, the thickness and morphology of the coating can be changed by altering the precursor temperature in CVD. However, the coating produced by CVD showed delamination because of low adhesion and stability. Hence, comprehensive studies are needed to analyze the delamination or degradation mechanism of coatings before the application on orthopedic devices. In the electrochemical deposition process, a tightly adherent and thin coating of oxide, salt, or metal is deposited onto the substrate surface by electrolysis of a solution containing the metal ion or its chemical complex.
In the sol-gel method, a substrate is dipped into a colloidal suspension, and a gel layer is deposited onto the substrate surface. Then the excess liquid is removed by a drying process [83]. This method is widely used to create complex thin coating geometries with high homogeneity and purity. This method is used to coat metallic implant materials to enhance corrosion resistance. In addition, the sol-gel process is low-cost, which is used to maintain the parent mechanical properties of substrate because of the sol-gel nature and low processing temperature. However, this method has disadvantages as high permeability, low wear resistance, and cracking. The sol-gel process is sensitive to the coating material and the delamination occurs due to the difference in properties of substrate and coating material. Hence, further research is needed on substrate materials as the difference in thermal properties between the coating and the substrate cause delamination of coating and process failure. Hence, further research is needed to improve the degree of crystallinity and adhesion strength.
Plasma spraying is used to produce deposition rapidly with low thermal degradation as compared to other thermal coating techniques [84]. Presently, plasma-sprayed HA is the only coating approved by FDA [85]. Although this technique is effective to deposit HA coating on a metallic surface, it showed low crystallinity as increasing temperature disrupts the apatite layer. Moreover, this technique exhibits low adhesion strength and cracks may be developed. However, more research is required to improve the quality of coating with better adhesion and durability. The research trend is to showcase improved efficacy, performance, and durability of biomedical implants because the contemporary technique is still not able to meet the desired goals.
A relatively plausible option for manufacturing a micro-porous, rough, and hard coating on metal substrates is micro-arc-oxidation (MAO). This method is inviting some serious attention as it could ensure significant adhesive characteristics between the coating and substrate. Secondly, researchers see it as a promising technique regarding the formation of a good crystalline coating with morphologies having a porous exterior. Furthermore, the said process is easy to operate, cost-effective, and environment-friendly. Fortunately, this method can produce multifunctional well as protective coatings by adjusting the processing parameters. However, this process and the characteristics of its final product depend on several factors. Most importantly, those factors include electric parameters, electrolyte composition, substrate material used, and geometry of the electrolytic cell. The complex interdependence of these factors makes this technique quite challenging. At the current level of our research, it would be unwise to draw some conclusions with certainty regarding the feasibility of MAO to produce hydroxyapatite coating without subsequent treatment. Furthermore, it has been observed that this process leads to the formation of porosities which can lead to corrosion and delamination. In addition, this method is not suitable to coat bioactive materials on metallic implants. So, further investigations are needed to resolve complications.

3. Coatings for Metallic Implants

3.1. Coatings for Titanium

The most used titanium alloys for biomedical applications are Ti6Al4V and Ti6Al7Nb. These alloys are widely used in orthopedic applications because of their good corrosion resistance, high impact, fatigue strength, low density, inherent toughness, and lightness. However, their biological inertness shows some negative responses to cell and tissue behavior. So, both the new bone tissues and osteoblasts cannot grow well. Therefore, the bonding between host tissues and implants are not formed easily, which leads to poor osteointegration. As a result, Ti-based implant is detached from the host tissue in long-term implantation [86]. Another important cause of implant failure is an infection, which is caused by improper surgery, or bacterial activity in a physiological environment [87]. Hence, the ideal implant should be able to promote osteointegration, deter bacterial adhesion, and minimize prosthetic infections [88].
Several coating materials have been suggested for surface modifications of Ti implant material to enhance biocompatibility. Calcium phosphate-based biocompatible materials such as hydroxyapatite (HA), bioactive glass (BG), and biphasic calcium phosphate (BCP) are widely used for the replacement or repair of different implants due to their excellent biocompatibility, osteoconductivity, and osteointegration.
To enhance the biocompatibility of titanium, Behera et al. [86] deposited the BCP coating on Ti-6Al-4V and studied the influence of coating thickness on bioactivity, wettability, and mechanical properties. In vitro bioactivity of samples was evaluated by the formation of the apatite layer after immersion in SBF. The apatite film deposited on the surface of coated titanium provides the required surface chemistry for cell proliferation and adherence. Surface analysis confirms the formation of small elliptical and globular-like structures of apatite film on the coated titanium surface. Further, the wt.% of apatite layer enhances with the immersion time. The results of the study in terms of wt. % of HA and β-TCP over coated substrates before the immersion and after the immersion for 14 days are presented in Figure 1. Moreover, the phase analysis confirms the presence of HA peaks with no β-TCP phases. Therefore, it can be concluded that BCP-coated titanium samples exhibit good bioactivity due to the growth of apatite precipitation.
The undesirable bioactivity on the titanium surface such as lack of osteoinduction is a major contributing factor for the failure of implants. Li et al. [89] proposed that the incorporation of strontium (Sr) in calcium silicates and calcium phosphates can further improve the osteoinduction of orthopedic implants. The Sr-incorporated calcium phosphate (P-Sr) and Sr-incorporated calcium silicate (Si-Sr) on Ti alloy were prepared by micro-arc oxidation (MAO) and the biological properties of the two coatings were compared. The results in terms of cell adhesion and cell proliferation are presented in Figure 2. The cell number and OD values of coated and uncoated samples increased with incubation time. The results indicate that both coatings are effective to enhance corrosion resistance and promoting osteogenic differentiation ability. Both coatings not only can enhance the corrosion resistance and hydrophilic state of titanium (TC4) substrates but also promote bioactivity and osteogenic differentiation ability. In comparison to both coatings Si-Sr coating exhibit better biocompatibility.
Li et al. [90] prepared the chitosan/HA coating on the titanium surface to improve the biological and antibacterial properties of titanium implants. First, the micro-nano structured HA coating was prepared on the titanium surface by micro-arc oxidation (MAO), and then the antibacterial agent of chitosan was loaded on the HA surface through the dip-coating method. The results showed that the obtained chitosan/HA composite coating accelerated the formation of apatite layer in SBF solution, enhanced cell adhesion, spreading, and proliferation, and it also inhibited the bacterial growth, showing improved biological and antibacterial properties. Although, with the increased amount of chitosan, the coverage of HA coating would be enlarged, resulting in depressed biological property, however, the antibacterial property was improved.
An antibacterial study is a necessary condition for an implant material because infectious adulteration is a prime source of concern during implant surgery. Hussein et al. [91] analyzed the antibacterial, biocorrosion, and mechanical performance of TiN coating on the titanium surface. Antibacterial activity was performed on TiN-coated titanium substrates against bacteria. The TiN-coated samples showed improved antibacterial properties as compared to uncoated samples due to the change in surface characteristics. The Ti surface exhibits higher sensitivity to bacterial adhesion due to the dissolution of oxide/passive films. The TiN coated surface exhibit antibacterial activity due to physical obstruction to the bacterial adhesion. The results of the study are presented in Figure 3.
To improve the overall performance of orthopedic implants, it is essential to consider the other performance parameters including mechanical properties, corrosion, and wear behavior. The use of multi-coating materials can be effective to achieve the desired properties. And the investigation of these properties is essential in determining the implant performance. To improve the corrosion resistance with cytocompatibility and bioactivity, Sun et al. [92] deposited the multifunctional hybrid layer of BCP/Tantalum pentoxide (Ta2O5) on the titanium surface. First, the Ta2O5 layer was deposited on the titanium surface by the hydration condensation process. Then an electrochemical deposition method was used to deposit the BCP layer on the coated substrates. The results indicate that the Ta2O5 improves the corrosion resistance while the BCP layer promotes surface bioactivity, hydrophilicity, and bone cell adhesion. In vitro electrochemical potentiodynamic polarization test was performed to evaluate the corrosion behavior of the coating surface. The results of corrosion tests are presented in Figure 4. The results show that the coated samples show lower corrosion potential as compared to untreated samples. The corrosion current densities of test samples were in following order: BCPs/Ta2O5/titanium (0.2 µA/cm2) < Ta2O5/titanium (1.2 µA/cm2) < titanium (3.5 µA/cm2). These results show that the presence of amorphous Ta2O5 coating film decreased the current density of the titanium by approximately 65%, and the presence of crystalline BCP layer further decreased the current density of the Ta2O5/titanium by approximately 80%. Hence decreased current density and ion release due to the inner Ta2O5 and outer BCPs layer of the titanium surface indicate the enhanced corrosion resistance.
Several coatings have been produced on the titanium surface to enhance the wear resistance of the implant. Cui et al. [93] proposed the TiN coating for wear performance enhancement. The monolayer and graded TiN coatings were deposited on the titanium surface by DC reactive magnetron sputtering. The elastic modulus and hardness of coating specimens were measured under nano-indentation tests. The continuous and smooth curve suggests that the TiN coating exhibits good crack resistance. The results of the study are presented in Figure 5a. The ball-on-disc tests were performed to evaluate the wear performance of specimens in Hank’s solution under the load of 10 N. The change of coefficient of friction (COF) with time under the sliding abrasion test is shown in Figure 5b. A 50% reduction in COF was observed for graded TiN coating as compared to monolayer TiN coating.
The adhesion strength and degradation behavior of coatings are important influencing parameters for performance analysis. Cao et al. [94] compared the four coating groups including Polylactide-L-lactide-CO-ε-caprolactone (PLC) coatings, PLC coating with antibiotics, micro-arc oxidation (MAO)/PLC double coating, and MAO/PLC double coating with antibiotics on titanium surface. The result shows that the use of MAO coating is very effective to increase the adhesion strength and load to failure of coating at the interface. The degradation test shows that the addition of antibiotics causes the loss of coating mass. The results of the study are presented in Figure 6. The study concludes that the MAO/PLC double coating has a good potential for reducing the severity and incidence of implant-related early infections.
To minimize the stress shielding effect of titanium implants, the use of porous titanium implants instead of fully dense titanium implants has been reported in the literature. Moriche et al. [95] reported that porous titanium substrates exhibit lower mechanical properties, closer to those of human bones as compared to fully dense titanium substrates. Torres et al. [96] fabricated the porous titanium substrates and deposited the gelatin coatings on these substrates to improve the biocompatibility. Silver nanoparticles have been described to damage bacterial cells via prolonged release of Ag+ ions as a mode of action when immobilized on a surface [97]. To improve the antibacterial properties, Gaviria et al. [98] deposited the therapeutic Ag nanoparticles coatings on porous titanium substrates. The results showed that the coated porous titanium substrates exhibit lower antibacterial activity as compared to fully dense titanium substrates. As bioactive glass coating on titanium surface offers improved bioactivity and mechanical properties. So, Moriche et al. [95] evaluated the potential of bioactive glass coatings on porous titanium substrates. The results showed that bioactive glass-coated porous substrates exhibit improved mechanical properties with higher bioactivity due to the formation of a hydroxyapatite layer. Beltran et al. [99,100] coated porous titanium substrates with a bilayer of bioactive glasses to overcome the problems associated with titanium implants such as poor osseointegration and stress shielding.
The results of few recent studies are summarized in Table 3 and many other studies are reviewed to conclude the influence of coatings on titanium surface for orthopedic applications. Calcium phosphate-based coatings such as HA and BCP have been shown to induce bone formation and promote bone-implant integration [101,102,103,104,105,106]. The coated titanium become bioactive and biocompatible because of their surface characteristics due to the formation of the apatite layer. Unfortunately, poor mechanical performance has hindered these from becoming favorable coating materials. Most present studies have focused on incorporating different elements into HA or BCP coatings to improve mechanical or corrosion properties [107,108,109,110,111,112,113]. Few studies showed that the incorporation of tantalum (Ta), chitosan, Graphene-oxide (GO), and biodegradable metals, and TiO2 in HA or BCP is effective to achieve the required properties. Similarly introducing the inner layer is also effective to achieve the multifunction’s of hybrid coatings [114,115,116]. The results show that these composites or multifunctional hybrid coatings are effective to improve biocompatibility, biocorrosion, and mechanical properties with the compromise of surface roughness and friction properties. Another challenge associated with these coatings is the adhesion strength which limits the use of these coatings on an industrial scale. Introducing the interface or seed layer can be helpful to improve the surface roughness and adhesion strength of calcium phosphate-based coatings [117].
The results in Table 3 show that many coating techniques have been employed to coat metal implant materials. Physical vapor deposition techniques including magnetron sputtering and cathodic arc physical deposition have been used effectively to achieve uniform distribution of bioactive glass, and TiN coatings with good adhesion strength and scratch resistance [86,93]. The grain size and microstructure of coatings can be controlled by controlling processing parameters. The processing parameters such as temperature, pressure, power, etc., are important to control the coating quality. Further optimization of these processing parameters can be effective to achieve high-quality coatings.
In comparison to HA and BCP coatings, TiN coatings showed improved corrosion, tribological, mechanical, antibacterial, and biological properties. The significant enhancement in all-determining parameters can be easily observed from tabular data for TiN coated specimens. Particularly, TiN coating is beneficial to enhance the mechanical properties up to 3 to 7 times. As per the data of two studies the hardness increased above 7 times as compared to the uncoated titanium surface. As another study showed that the hardness increased 4 times for TiN coated specimens. The data of these three studies showed that the elastic modulus of TiN coated specimens increased 2 to 4 times as compared to uncoated specimens. The corrosion tests showed that the corrosion current density of TiN coated specimens is very low as compared to uncoated specimens. The mean TiN coating showed good corrosion resistance. The tribological results showed a significant reduction in (up to 50%) COF and wear rate for TiN coated specimens. The biocompatibility tests show that the TiN coatings are biocompatible to some extent and better than uncoated titanium specimens. The bacterial studies show that the TiN coating exhibit antibacterial properties. Hence the results showed that the TiN coatings fulfill the required criteria for orthopedic applications. But before the use of these coatings, degradation studies are needed to be conducted for the long-term time. Further, the durability of TiN coating is needed to be investigated in long-term vitro and vivo studies. The studies on other coating materials including diamond-like carbon, Polylactide-L-lactide-CO-ε-caprolactone (PLC), TiTaHfNbZr, etc. are still insufficient, and results of such coatings are not attractive to perform more studies on these coating materials.

3.2. Coatings for Stainless Steel

Stainless steel is the most used material because of its low cost and high mechanical properties. Therefore, it is still used for making many orthopedic implant components like fixation screws, bone plates, etc. However, stainless steel is the least biocompatible and anticorrosive, and it does not integrate with bone naturally and might release some toxic ions and corrosion products. The metal implant encapsulated by body tissues released ions into the body which can become the cause of loosening and failure of the implant. A coating of bioactive materials on the stainless steel is a practical solution to induce osteointegration by decreasing or suppressing the released products. In addition, these coatings should be antibacterial. Several bioactive and antibacterial coatings have been used for stainless steel implants. Many investigations have been carried out to improve the biocompatibility, biocorrosion, and antibacterial properties of stainless steel by depositing BG or composites coatings containing BG [122,123,124,125,126,127,128]. BG-coated stainless-steel implants provide better integration to the body tissues by forming apatite at the coated metal surface. Furthermore, they can inhibit or regulate corrosion in the physiobiological environment [129]. To improve the further biocompatibility, antibacterial, and corrosion properties various materials including silane, chitosan, silica, gelatin, polyether ether ketone (PEEK), Zein, a natural fibroblast and copper, etc. have been added in BG to make composites coatings. Cuevas et al. [130] prepared the HA-loaded BG coated stainless steel substrates, and then evaluated their bioactivity in SBF solution. The thickness of the apatite layer and released ions concentration in the immersion test were observed for coated specimens. The results show that the addition of HA in BG is effective to increase the thickness of the apatite layer. The thickness formation rate at the start of soaking was higher, while a significant reduction in growth rate was observed after the 5 days of soaking. Furthermore, ion release behavior in the immersion test was the same for all types samples. Al-Rashidy et al. [131] used the electrophoretic co-deposition technique to coat stainless steel with three different BG compositions and studied the corrosion behavior. The achieved coatings were homogenous, uniform, and crack-free. The pH change and the concentration of calcium ions were measured in the immersion test. The decrease in pH and increase in released Ca ions were observed due to the formation of HA crystals on the substrate surface. The results shown in Figure 7 showed that all the BG coating layers have a better ability to form HA crystal on their surface.
The deposition of the HA layer on stainless steel is also effective to enhance the bioactivity and corrosion resistance of stainless-steel implant materials. Rezaei et al. [132] deposited the HA-10wt.%Mg and HA-30wt.%Mg coating on the stainless steel for biomedical implants. The objective of the intermediate layer was to improve corrosion resistance while Mg particles were added to improve the osseointegration process by forming porosities in the physiological environment. The results of the study are presented in Figure 8. The results show that the HA-coated samples exhibit lower corrosion current densities and higher cell viability as compared to uncoated samples.
The results of different coatings on stainless steel are summarized in Table 4. The studies revealed that the HA and BG both are suitable coating materials to enhance the corrosion, bioactivity, and antibacterial characteristics. Such coatings exhibit weaker adhesion and still, there is needed to improve the adhesion strength. Poor adhesion between metallic and coating interface leads to failure and unsuitable for high load-bearing applications. Poor crystalized formation on metallic implant material caused the coating to dissolve and decrease adherence to a metallic surface. The failure occurs at the interface in case of long-term use. Therefore, the stability of HA and BG coatings are the most important factors to determine the success of steel implants. Several additive materials such as gelatin, PEEK, polyvinyl alcohol (PVA), etc. have been added in BG to improve the adhesion. So, there is needed to improve the adhesion stability and degradation behavior of coatings.

3.3. Coatings for Cobalt-Chrome Molybdenum (CoCrMo) Alloys

CoCrMo alloys exhibit favorable bioactivity with good corrosion and mechanical properties. Therefore, these alloys are widely used in orthopedic applications, especially for manufacturing knee and hip implants. Many methods have been employed to improve biocompatibility and other properties. Despite the high corrosion resistance of CoCrMo alloys due to the presence of thin oxide film, dangerous ions like Ni, Co, Cr are released in the body from CoCrMo prosthesis components. The elevated concentration of these ions may lead to the inflammatory response and implant failure after the joint implantation.
Leonberger et al. [142] performed the surface modifications on a CoCrMo alloy surface to improve the biocompatibility of these alloys. Five different CoCrMo substrates including uncoated, TiN coated, polished, porous polished, and pure Titanium (cpTi) coated were compared in terms of cytotoxicity and cell viability, and their osteoblast potential was evaluated. The cell viability test showed the evenly spread of cells on all the modified surfaces. All modified samples showed increased cell viability and the highest cell viability was observed for TiN coated alloy as shown in Figure 9a. The cytotoxicity test showed no significant changes as shown in Figure 9b. Lactate dehydrogenase (LDH) is released from the disrupted membranes. The membrane is disrupted in necrotic cells and LDH is released from the cell. The LDH release remained stable for all substrates. Hence, the TiN coatings showed good compatibility and prevent the CoCrMo surface from encountering the tissues. Furthermore, TiN coated specimens showed good corrosion resistance and reduced the released ions from CoCrMo base material.
Doring et al. [143] deposited the TiN, ZrN, and diamond-like carbon (DLC) coatings on CoCrMo alloy and performed the friction and wear studies. The lower values of coefficient of friction (COF) were recorded for TiN coated substrate as shown in Figure 10. The low COF of about 0.094 is attributed to the very smooth surface achieved by cathodic arc deposition.
The results of different studies are summarized in Table 5. The results showed that HA, TiN, and TiSIN coatings exhibit better performance as compared to other listed coatings.

4. Conclusions

Titanium, stainless steel, and CoCrMo alloys are the most widely used biomaterials for orthopedic applications. The most common causes of orthopedic implant failure after implantation are infections, inflammatory response, least corrosion resistance, mismatch in elastic modulus, stress shielding, and excessive wear. To address the problems associated with implant materials, different modifications related to design, materials, and surface have been developed. Among the different methods, coating is an effective method to improve the performance of implant materials. In this article, a comprehensive review of recent studies has been carried out to summarize the impact of coating materials on metallic implants. The antibacterial characteristics, biodegradability, biocompatibility, corrosion behavior, and mechanical properties for performance evaluation are briefly summarized.
Many coating techniques such as physical vapor deposition, chemical vapor deposition, electrochemical deposition, sol-gel, plasma spraying, and micro-arc oxidation have been used in recent years to coat metallic implants. Among these techniques physical vapor deposition techniques including cathodic arc deposition, DC reactive magnetron sputtering, close field magnetron sputter ion plating, etc. are effective techniques to produce the coating with improved biocompatibility, corrosion resistance, and mechanical properties. A significant enhancement in performance is reported for several coating materials including HA, BG, and TiN. However, the stability, adhesion, and degradation performance of these coatings are challenges and limiting the use of these coatings on an industrial scale.
Many recent studies showed that the incorporation of tantalum (Ta), chitosan, Graphene-oxide (GO), and biodegradable metals, and TiO2 in HA or BCP is effective to achieve the required properties. Similarly introducing the inner layer is also effective to achieve the multifunction’s of hybrid coatings. The results show that these composites or multifunctional hybrid coatings are effective to improve biocompatibility, bio-corrosion, and mechanical properties. In comparison to HA and BCP coatings, TiN coatings showed improved corrosion, tribological, mechanical, antibacterial, and biological properties.

Author Contributions

Methodology, M.H. and M.A.B.; data curation, M.H., S.H.A.R., N.A., M.R.S. and M.A.B.; formal analysis, S.H.A.R. and U.S.; investigation, N.A. and M.A.B.; supervision, N.A. and M.A.B.; writing—original draft, M.H. and N.A.; resources, M.R.S.; funding acquisition, A.I.M. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Data is contained within the article.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Brach del Prever, E.M.; Costa, L.; Piconi, C.; Baricco, M.; Massè, A. Biomaterials for total joint replacements. In Biomechanics and Biomaterials in Orthopedics, 2nd ed.; Springer: London, UK, 2016; pp. 59–70. [Google Scholar]
  2. Krishnakumar, S.; Senthilvelan, T. Polymer composites in dentistry and orthopedic applications-a review. Mater. Today Proc. 2020. [Google Scholar] [CrossRef]
  3. Goswami, C.; Patnaik, A.; Bhat, I.K.; Singh, T. Mechanical physical and wear properties of some oxide ceramics for hip joint application: A short review. Mater. Today Proc. 2021. [Google Scholar] [CrossRef]
  4. Jones, L.C.; Timmie Topoleski, L.D.; Tsao, A.K. Biomaterials in orthopaedic implants. In Mechanical Testing of Orthopaedic Implants; Elsevier: Amsterdam, The Netherlands, 2017; pp. 17–32. ISBN 9780081002865. [Google Scholar]
  5. Sharma, A.; Sharma, G. Biomaterials and their applications. In AIP Conference Proceedings; American Institute of Physics Inc.: Melville, NY, USA, 2018; Volume 1953, p. 080041. [Google Scholar]
  6. Radha, R.; Sreekanth, D. Insight of magnesium alloys and composites for orthopedic implant applications—A review. J. Magnes. Alloy. 2017, 5, 286–312. [Google Scholar] [CrossRef]
  7. Ali, M.; Hussein, M.A.; Al-Aqeeli, N. Magnesium-based composites and alloys for medical applications: A review of mechanical and corrosion properties. J. Alloy. Compd. 2019, 792, 1162–1190. [Google Scholar] [CrossRef]
  8. Song, M.S.; Zeng, R.C.; Ding, Y.F.; Li, R.W.; Easton, M.; Cole, I.; Birbilis, N.; Chen, X.B. Recent advances in biodegradation controls over Mg alloys for bone fracture management: A review. J. Mater. Sci. Technol. 2019, 35, 535–544. [Google Scholar] [CrossRef]
  9. Jaiswal, S.; Dubey, A.; Lahiri, D. In Vitro Biodegradation and Biocompatibility of Mg–HA-Based Composites for Orthopaedic Applications: A Review. J. Indian Inst. Sci. 2019, 99, 303–327. [Google Scholar] [CrossRef]
  10. Shahin, M.; Munir, K.; Wen, C.; Li, Y. Magnesium matrix nanocomposites for orthopedic applications: A review from mechanical, corrosion, and biological perspectives. Acta Biomater. 2019, 96, 1–19. [Google Scholar] [PubMed]
  11. Xia, L.; Xie, Y.; Fang, B.; Wang, X.; Lin, K. In situ modulation of crystallinity and nano-structures to enhance the stability and osseointegration of hydroxyapatite coatings on Ti-6Al-4V implants. Chem. Eng. J. 2018, 347, 711–720. [Google Scholar] [CrossRef]
  12. Gobbi, S. Wear Resistance of Metallic Orthopedic Implants—Mini Review. Biomed. J. Sci. Tech. Res. 2018, 12. [Google Scholar] [CrossRef]
  13. Xu, W.; Yu, A.; Lu, X.; Tamaddon, M.; Ng, L.; Dilawer Hayat, M.; Wang, M.; Zhang, J.; Qu, X.; Liu, C. Synergistic interactions between wear and corrosion of Ti-16Mo orthopedic alloy. J. Mater. Res. Technol. 2020, 9, 9996–10003. [Google Scholar] [CrossRef]
  14. Xu, W.; Lu, X.; Tian, J.; Huang, C.; Chen, M.; Yan, Y.; Wang, L.; Qu, X.; Wen, C. Microstructure, wear resistance, and corrosion performance of Ti35Zr28Nb alloy fabricated by powder metallurgy for orthopedic applications. J. Mater. Sci. Technol. 2020, 41, 191–198. [Google Scholar] [CrossRef]
  15. Priyadarshini, B.; Rama, M.; Chetan; Vijayalakshmi, U. Bioactive coating as a surface modification technique for biocompatible metallic implants: A review. J. Asian Ceram. Soc. 2019, 7, 397–406. [Google Scholar] [CrossRef] [Green Version]
  16. Saad, M.; Akhtar, S.; Srivastava, S. Composite Polymer in Orthopedic Implants: A Review. In Proceedings of the Materials Today: Proceedings; Elsevier: Amsterdam, The Netherlands, 2018; Volume 5, pp. 20224–20231. [Google Scholar]
  17. Xia, C.; Ma, X.; Zhang, X.; Li, K.; Tan, J.; Qiao, Y.; Liu, X. Enhanced physicochemical and biological properties of C/Cu dual ions implanted medical titanium. Bioact. Mater. 2020, 5, 377–386. [Google Scholar] [CrossRef]
  18. Al-Tamimi, A.A.; Peach, C.; Fernandes, P.R.; Cseke, A.; Bartolo, P.J.D.S. Topology Optimization to Reduce the Stress Shielding Effect for Orthopedic Applications. In Procedia CIRP; Elsevier B.V.: Amsterdam, The Netherlands, 2017; Volume 65, pp. 202–206. [Google Scholar]
  19. Limmahakhun, S.; Oloyede, A.; Sitthiseripratip, K.; Xiao, Y.; Yan, C. Stiffness and strength tailoring of cobalt chromium graded cellular structures for stress-shielding reduction. Mater. Des. 2017, 114, 633–641. [Google Scholar] [CrossRef]
  20. Zhang, L.; Song, B.; Choi, S.-K.; Shi, Y. A Topology Strategy to Reduce Stress Shielding of Additively Manufactured Porous Metallic Biomaterials. Int. J. Mech. Sci. 2021, 197, 106331. [Google Scholar] [CrossRef]
  21. Vijayavenkataraman, S.; Gopinath, A.; Lu, W.F. A new design of 3D-printed orthopedic bone plates with auxetic structures to mitigate stress shielding and improve intra-operative bending. Bio-Des. Manuf. 2020, 3, 98–108. [Google Scholar] [CrossRef]
  22. Raffa, M.L.; Nguyen, V.; Hernigou, P.; Flouzat-Lachaniette, C.; Haiat, G. Stress shielding at the bone-implant interface: Influence of surface roughness and of the bone-implant contact ratio. J. Orthop. Res. 2020, 39, 1174–1183. [Google Scholar] [CrossRef]
  23. Ait Moussa, A.; Fischer, J.; Yadav, R.; Khandaker, M. Minimizing Stress Shielding and Cement Damage in Cemented Femoral Component of a Hip Prosthesis through Computational Design Optimization. Adv. Orthop. 2017, 2017. [Google Scholar] [CrossRef] [Green Version]
  24. Lam, R.R.; Kondaiah, V.V.; Naidubabu, Y.; Dumpala, R.; Ratna Sunil, B. Effect of Crack Angle on Stress Shielding in Bone and Orthopedic Fixing Plate Implant: Design and Simulation. In Lecture Notes in Mechanical Engineering; Springer: Berlin/Heidelberg, Germany, 2021; pp. 785–792. [Google Scholar]
  25. Hosseinitabatabaei, S.; Ashjaee, N.; Tahani, M. Introduction of Maximum Stress Parameter for the Evaluation of Stress Shielding Around Orthopedic Screws in the Presence of Bone Remodeling Process. J. Med. Biol. Eng. 2017, 37, 703–716. [Google Scholar] [CrossRef]
  26. Kraus, T.; Fischerauer, S.; Treichler, S.; Martinelli, E.; Eichler, J.; Myrissa, A.; Zötsch, S.; Uggowitzer, P.J.; Löffler, J.F.; Weinberg, A.M. The influence of biodegradable magnesium implants on the growth plate. Acta Biomater. 2018, 66, 109–117. [Google Scholar] [CrossRef]
  27. Jadhav, P.; Bongale, A.; Kumar, S. Schematic review of plasma arc oxidation process for Mg Alloy Bio Implants. IOP Conf. Ser. Mater. Sci. Eng. 2021, 1017, 012011. [Google Scholar] [CrossRef]
  28. Kamrani, S.; Fleck, C. Biodegradable magnesium alloys as temporary orthopaedic implants: A review. BioMetals 2019, 32, 185–193. [Google Scholar] [CrossRef]
  29. Korhonen, L.; Perhomaa, M.; Kyrö, A.; Pokka, T.; Serlo, W.; Merikanto, J.; Sinikumpu, J.J. Intramedullary nailing of forearm shaft fractures by biodegradable compared with titanium nails: Results of a prospective randomized trial in children with at least two years of follow-up. Biomaterials 2018, 185, 383–392. [Google Scholar] [CrossRef]
  30. Ibrahim, M.Z.; Sarhan, A.A.D.; Yusuf, F.; Hamdi, M. Biomedical materials and techniques to improve the tribological, mechanical and biomedical properties of orthopedic implants—A review article. J. Alloy. Compd. 2017, 714, 636–667. [Google Scholar] [CrossRef]
  31. Kaur, M.; Singh, K. Review on titanium and titanium based alloys as biomaterials for orthopaedic applications. Mater. Sci. Eng. C 2019, 102, 844–862. [Google Scholar] [CrossRef] [PubMed]
  32. Quinn, J.; McFadden, R.; Chan, C.W.; Carson, L. Titanium for Orthopedic Applications: An Overview of Surface Modification to Improve Biocompatibility and Prevent Bacterial Biofilm Formation. iScience 2020, 23, 101745. [Google Scholar] [CrossRef] [PubMed]
  33. Čapek, J.; Stehlíková, K.; Michalcová, A.; Msallamová, Š.; Vojtěch, D. Microstructure, mechanical and corrosion properties of biodegradable powder metallurgical Fe-2 wt% X (X = Pd, Ag and C) alloys. Mater. Chem. Phys. 2016, 181, 501–511. [Google Scholar] [CrossRef]
  34. Kraus, T.; Moszner, F.; Fischerauer, S.; Fiedler, M.; Martinelli, E.; Eichler, J.; Witte, F.; Willbold, E.; Schinhammer, M.; Meischel, M.; et al. Biodegradable Fe-based alloys for use in osteosynthesis: Outcome of an in vivo study after 52 weeks. Acta Biomater. 2014, 10, 3346–3353. [Google Scholar] [CrossRef] [PubMed]
  35. Manam, N.S.; Harun, W.S.W.; Shri, D.N.A.; Ghani, S.A.C.; Kurniawan, T.; Ismail, M.H.; Ibrahim, M.H.I. Study of corrosion in biocompatible metals for implants: A review. J. Alloy. Compd. 2017, 701, 698–715. [Google Scholar] [CrossRef] [Green Version]
  36. Hussain, M.; Naqvi, R.A.; Abbas, N.; Khan, S.M.; Nawaz, S.; Hussain, A.; Zahra, N.; Khalid, M.W. Ultra-High-Molecular-Weight-Polyethylene (UHMWPE) as a Promising Polymer Material for Biomedical Applications: A Concise Review. Polymers 2020, 12, 323. [Google Scholar] [CrossRef] [Green Version]
  37. Hussain, M.; Sufyan, M.; Abbas, N.; Ahmad, H.; Joyia, F.M.F.M.; Noman, M.; Ahsan, M.M.M.M.; Raza, M.N.M.N.; Razaq, A.; Zulqernain, M.; et al. Influence of laser processing conditions for texturing on ultra-high-molecular-weight-polyethylene (UHMWPE) surface. Case Stud. Therm. Eng. 2019, 14, 100491. [Google Scholar] [CrossRef]
  38. Sufyan, M.; Hussain, M.; Ahmad, H.; Abbas, N.; Ashraf, J.; Zahra, N. Bulge micro-textures influence on tribological performance of ultra-high-molecular-weight-polyethylene (UHMWPE) under phosphatidylcholine (Lipid) and bovine serum albumin (BSA) solutions. Biomed. Phys. Eng. Express 2019, 5, 035021. [Google Scholar] [CrossRef]
  39. Sequeira, S.; Fernandes, M.H.; Neves, N.; Almeida, M.M. Development and characterization of zirconia–alumina composites for orthopedic implants. Ceram. Int. 2017, 43, 693–703. [Google Scholar] [CrossRef]
  40. Gopal, V.; Manivasagam, G. Zirconia-alumina composite for orthopedic implant application. In Applications of Nanocomposite Materials in Orthopedics; Elsevier: Amsterdam, The Netherlands, 2018; pp. 201–219. ISBN 9780128137574. [Google Scholar]
  41. Baptista, A.; Silva, F.; Porteiro, J.; Míguez, J.; Pinto, G. Sputtering physical vapour deposition (PVD) coatings: A critical review on process improvement andmarket trend demands. Coatings 2018, 8, 402. [Google Scholar] [CrossRef] [Green Version]
  42. Jiang, X.; Yang, F.C.; Chen, W.C.; Lee, J.W.; Chang, C.L. Effect of nitrogen-argon flow ratio on the microstructural and mechanical properties of AlSiN thin films prepared by high power impulse magnetron sputtering. Surf. Coat. Technol. 2017, 320, 138–145. [Google Scholar] [CrossRef]
  43. Tang, J.F.; Lin, C.Y.; Yang, F.C.; Tsai, Y.J.; Chang, C.L. Effects of nitrogen-argon flow ratio on the microstructural and mechanical properties of AlCrN coatings prepared using high power impulse magnetron sputtering. Surf. Coat. Technol. 2020, 386, 125484. [Google Scholar] [CrossRef]
  44. Geyao, L.; Yang, D.; Wanglin, C.; Chengyong, W. Development and application of physical vapor deposited coatings for medical devices: A review. In Procedia CIRP.; Elsevier B.V.: Amsterdam, The Netherlands, 2020; Volume 89, pp. 250–262. [Google Scholar]
  45. Hussein, M.A.; Adesina, A.Y.; Kumar, A.M.; Sorour, A.A.; Ankah, N.; Al-Aqeeli, N. Mechanical, in-vitro corrosion, and tribological characteristics of TiN coating produced by cathodic arc physical vapor deposition on Ti20Nb13Zr alloy for biomedical applications. Thin Solid Film. 2020, 709, 138183. [Google Scholar] [CrossRef]
  46. Esmaeili, M.M.; Mahmoodi, M.; Imani, R. Tantalum carbide coating on Ti-6Al-4V by electron beam physical vapor deposition method: Study of corrosion and biocompatibility behavior. Int. J. Appl. Ceram. Technol. 2017, 14, 374–382. [Google Scholar] [CrossRef]
  47. Bobzin, K.; Brögelmann, T.; Kalscheuer, C.; Liang, T. Post-annealing of (Ti,Al,Si)N coatings deposited by high speed physical vapor deposition (HS-PVD). Surf. Coat. Technol. 2019, 375, 752–762. [Google Scholar] [CrossRef]
  48. Azar, G.T.P.; Yelkarasi, C.; Ürgen, M. The role of droplets on the cavitation erosion damage of TiN coatings produced with cathodic arc physical vapor deposition. Surf. Coat. Technol. 2017, 322, 211–217. [Google Scholar] [CrossRef]
  49. Kaliaraj, G.S.; Kamalan, K.K.; Alagarsamy, K.; Vishwakarma, V. Silver-ceria stabilized zirconia composite coatings on titanium for potential implant applications. Surf. Coat. Technol. 2019, 368, 224–231. [Google Scholar] [CrossRef]
  50. Qadir, M.; Li, Y.; Wen, C. Ion-substituted calcium phosphate coatings by physical vapor deposition magnetron sputtering for biomedical applications: A review. Acta Biomater. 2019, 89, 14–32. [Google Scholar] [CrossRef] [PubMed]
  51. Abbas, N.; Hussain, M.; Zahra, N.; Ahmad, H.; Mehdi, S.M.Z.; Amer, U.S.; Zain Mehdi, S.M.; Sajjad, U.; Amer, M. Optimization of Cr Seed Layer Effect for Surface Roughness of As-Deposited Silver Film using Electron Beam Deposition Method. J. Chem. Soc. Pak. 2020, 42, 23. [Google Scholar]
  52. Abbas, N.; Shad, M.R.; Hussain, M.; Mehdi, S.M.Z.; Sajjad, U. Fabrication and characterization of silver thin films using physical vapor deposition, and the investigation of annealing effects on their structures. Mater. Res. Express 2019, 6, 116437. [Google Scholar] [CrossRef]
  53. Jalil, S.A.; Ahmed, Q.S.; Akram, M.; Abbas, N.; Khalid, A.; Khalil, A.; Khalid, M.L.; Mehar, M.M.; Riaz, K.; Mehmood, M.Q. Fabrication of high refractive index TiO2 films using electron beam evaporator for all dielectric metasurfaces. Mater. Res. Express 2018, 5, 016410. [Google Scholar] [CrossRef]
  54. Joshi, P.; Haque, A.; Gupta, S.; Narayan, R.J.; Narayan, J. Synthesis of multifunctional microdiamonds on stainless steel substrates by chemical vapor deposition. Carbon N. Y. 2021, 171, 739–749. [Google Scholar] [CrossRef]
  55. Ullah, S.; Hasan, M.; Ta, H.Q.; Zhao, L.; Shi, Q.; Fu, L.; Choi, J.; Yang, R.; Liu, Z.; Rümmeli, M.H. Synthesis of Doped Porous 3D Graphene Structures by Chemical Vapor Deposition and Its Applications. Adv. Funct. Mater. 2019, 29, 1904457. [Google Scholar] [CrossRef]
  56. Nowak, D.; Januszewicz, B.; Niedzielski, P. Morphology, mechanical and tribological properties of hybrid carbon layer fabricated by Radio Frequency Plasma Assisted Chemical Vapor Deposition. Surf. Coat. Technol. 2017, 329, 1–10. [Google Scholar] [CrossRef]
  57. Morejón-Alonso, L.; Mochales, C.; Nascimento, L.; Müller, W.D. Electrochemical deposition of Sr and Sr/Mg-co-substituted hydroxyapatite on Ti-40Nb alloy. Mater. Lett. 2019, 248, 65–68. [Google Scholar] [CrossRef]
  58. Chakraborty, R.; Seesala, V.S.; Manna, J.S.; Saha, P.; Dhara, S. Synthesis, characterization and cytocompatibility assessment of hydroxyapatite-polypyrrole composite coating synthesized through pulsed reverse electrochemical deposition. Mater. Sci. Eng. C 2019, 94, 597–607. [Google Scholar] [CrossRef]
  59. Li, T.T.; Ling, L.; Lin, M.C.; Peng, H.K.; Ren, H.T.; Lou, C.W.; Lin, J.H. Recent advances in multifunctional hydroxyapatite coating by electrochemical deposition. J. Mater. Sci. 2020, 55, 6352–6374. [Google Scholar] [CrossRef]
  60. Cotrut, C.M.; Vladescu, A.; Dinu, M.; Vranceanu, D.M. Influence of deposition temperature on the properties of hydroxyapatite obtained by electrochemical assisted deposition. Ceram. Int. 2018, 44, 669–677. [Google Scholar] [CrossRef]
  61. Lopes, N.I.A.; Henrique Jardim Freire, N.; Resende, P.D.; Santos, L.A.; Buono, V.T.L. Electrochemical deposition and characterization of ZrO2 ceramic nanocoatings on superelastic NiTi alloy. Appl. Surf. Sci. 2018, 450, 21–30. [Google Scholar] [CrossRef]
  62. Wang, X.; Yan, L.; Ye, T.; Cheng, R.; Tian, J.; Ma, C.; Wang, Y.; Cui, W. Osteogenic and antiseptic nanocoating by in situ chitosan regulated electrochemical deposition for promoting osseointegration. Mater. Sci. Eng. C 2019, 102, 415–426. [Google Scholar] [CrossRef]
  63. Fathyunes, L.; Khalil-Allafi, J. The effect of graphene oxide on surface features, biological performance and bio-stability of calcium phosphate coating applied by pulse electrochemical deposition. Appl. Surf. Sci. 2018, 437, 122–135. [Google Scholar] [CrossRef]
  64. Asri, R.I.M.; Harun, W.S.W.; Hassan, M.A.; Ghani, S.A.C.; Buyong, Z. A review of hydroxyapatite-based coating techniques: Sol-gel and electrochemical depositions on biocompatible metals. J. Mech. Behav. Biomed. Mater. 2016, 57, 95–108. [Google Scholar] [CrossRef] [Green Version]
  65. Ferraris, S.; Spriano, S. Antibacterial titanium surfaces for medical implants. Mater. Sci. Eng. C 2016, 61, 965–978. [Google Scholar] [CrossRef]
  66. Yu, S.; Li, Z.; Han, L.; Zhao, Y.; Fu, T. Biocompatible MgO Film on Titanium Substrate Prepared by Sol-gel Method. Xiyou Jinshu Cailiao Yu Gongcheng/Rare Met. Mater. Eng. 2018, 47, 2663–2667. [Google Scholar] [CrossRef]
  67. Catauro, M.; Bollino, F.; Giovanardi, R.; Veronesi, P. Modification of Ti6Al4V implant surfaces by biocompatible TiO2/PCL hybrid layers prepared via sol-gel dip coating: Structural characterization, mechanical and corrosion behavior. Mater. Sci. Eng. C 2017, 74, 501–507. [Google Scholar] [CrossRef]
  68. Choi, G.; Choi, A.H.; Evans, L.A.; Akyol, S.; Ben-Nissan, B. A review: Recent advances in sol-gel-derived hydroxyapatite nanocoatings for clinical applications. J. Am. Ceram. Soc. 2020, 103, 5442–5453. [Google Scholar] [CrossRef]
  69. Kaur, S.; Bala, N.; Khosla, C. Characterization of Hydroxyapatite Coating on 316L Stainless Steel by Sol–Gel Technique. Surf. Eng. Appl. Electrochem. 2019, 55, 357–366. [Google Scholar] [CrossRef]
  70. Jaafar, A.; Hecker, C.; Árki, P.; Joseph, Y. Sol-gel derived hydroxyapatite coatings for titanium implants: A review. Bioengineering 2020, 7, 127. [Google Scholar] [CrossRef]
  71. Shahali, H.; Jaggessar, A.; Yarlagadda, P.K.D.V. Recent Advances in Manufacturing and Surface Modification of Titanium Orthopaedic Applications. In Procedia Engineering; Elsevier: Amsterdam, The Netherlands, 2017; Volume 174, pp. 1067–1076. [Google Scholar]
  72. Sun, L. Thermal Spray Coatings on Orthopedic Devices: When and How the FDA Reviews Your Coatings. J. Therm. Spray Technol. 2018, 27, 1280–1290. [Google Scholar] [CrossRef] [Green Version]
  73. Fox, K.E.; Tran, N.L.; Nguyen, T.A.; Nguyen, T.T.; Tran, P.A. Surface modification of medical devices at nanoscale-recent development and translational perspectives. In Biomaterials in Translational Medicine: A Biomaterials Approach; Elsevier: Amsterdam, The Netherlands, 2018; pp. 163–189. ISBN 9780128134771. [Google Scholar]
  74. Ullah, I.; Siddiqui, M.A.; Liu, H.; Kolawole, S.K.; Zhang, J.; Zhang, S.; Ren, L.; Yang, K. Mechanical, Biological, and Antibacterial Characteristics of Plasma-Sprayed (Sr,Zn) Substituted Hydroxyapatite Coating. ACS Biomater. Sci. Eng. 2020, 6, 1355–1366. [Google Scholar] [CrossRef]
  75. Badshah, M.A.; Koh, N.Y.; Zia, A.W.; Abbas, N.; Zahra, Z.; Saleem, M.W. Recent developments in plasmonic nanostructures for metal enhanced fluorescence-based biosensing. Nanomaterials 2020, 10, 1749. [Google Scholar] [CrossRef]
  76. He, X.; Zhang, X.; Wang, X.; Qin, L. Review of Antibacterial Activity of Titanium-Based Implants’ Surfaces Fabricated by Micro-Arc Oxidation. Coatings 2017, 7, 45. [Google Scholar] [CrossRef] [Green Version]
  77. Qadir, M.; Li, Y.; Munir, K.; Wen, C. Calcium Phosphate-Based Composite Coating by Micro-Arc Oxidation (MAO) for Biomedical Application: A Review. Crit. Rev. Solid State Mater. Sci. 2018, 43, 392–416. [Google Scholar] [CrossRef]
  78. Zhang, X.; Peng, Z.; Lu, X.; Lv, Y.; Cai, G.; Yang, L.; Dong, Z. Microstructural evolution and biological performance of Cu-incorporated TiO2 coating fabricated through one-step micro-arc oxidation. Appl. Surf. Sci. 2020, 508, 144766. [Google Scholar] [CrossRef]
  79. Dehghanghadikolaei, A.; Ibrahim, H.; Amerinatanzi, A.; Hashemi, M.; Moghaddam, N.S.; Elahinia, M. Improving corrosion resistance of additively manufactured nickel–titanium biomedical devices by micro-arc oxidation process. J. Mater. Sci. 2019, 54, 7333–7355. [Google Scholar] [CrossRef]
  80. Tang, H.; Han, Y.; Wu, T.; Tao, W.; Jian, X.; Wu, Y.; Xu, F. Synthesis and properties of hydroxyapatite-containing coating on AZ31 magnesium alloy by micro-arc oxidation. Appl. Surf. Sci. 2017, 400, 391–404. [Google Scholar] [CrossRef]
  81. Vernardou, D.; Parkin, I.P.; Drosos, C. Chemical vapor deposition of oxide materials at atmospheric pressure. In Handbook of Modern Coating Technologies; Elsevier: Amsterdam, The Netherlands, 2021; pp. 101–119. [Google Scholar]
  82. Sun, L.; Yuan, G.; Gao, L.; Yang, J.; Chhowalla, M.; Gharahcheshmeh, M.H.; Gleason, K.K.; Choi, Y.S.; Hong, B.H.; Liu, Z. Chemical vapour deposition. Nat. Rev. Methods Prim. 2021, 1, 5. [Google Scholar] [CrossRef]
  83. Prodan, A.M.; Iconaru, S.L.; Predoi, M.V.; Predoi, D.; Motelica-Heino, M.; Turculet, C.S.; Beuran, M. Silver-doped hydroxyapatite thin layers obtained by sol-gel spin coating procedure. Coatings 2020, 10, 14. [Google Scholar] [CrossRef] [Green Version]
  84. Tejero-Martin, D.; Rezvani Rad, M.; McDonald, A.; Hussain, T. Beyond Traditional Coatings: A Review on Thermal-Sprayed Functional and Smart Coatings. J. Therm. Spray Technol. 2019, 28, 598–644. [Google Scholar] [CrossRef] [Green Version]
  85. Aruna, S.T.; Kulkarni, S.; Chakraborty, M.; Kumar, S.S.; Balaji, N.; Mandal, C. A comparative study on the synthesis and properties of suspension and solution precursor plasma sprayed hydroxyapatite coatings. Ceram. Int. 2017, 43, 9715–9722. [Google Scholar] [CrossRef]
  86. Behera, R.R.; Das, A.; Pamu, D.; Pandey, L.M.; Sankar, M.R. Mechano-tribological properties and in vitro bioactivity of biphasic calcium phosphate coating on Ti-6Al-4V. J. Mech. Behav. Biomed. Mater. 2018, 86, 143–157. [Google Scholar] [CrossRef]
  87. Li, Y.; Yang, Y.; Li, R.; Tang, X.; Guo, D.; Qing, Y.; Qin, Y. Enhanced antibacterial properties of orthopedic implants by titanium nanotube surface modification: A review of current techniques. Int. J. Nanomed. 2019, 14, 7217–7236. [Google Scholar] [CrossRef] [Green Version]
  88. Zhang, B.G.X.; Myers, D.E.; Wallace, G.G.; Brandt, M.; Choong, P.F.M. Bioactive coatings for orthopaedic implants-recent trends in development of implant coatings. Int. J. Mol. Sci. 2014, 15, 11878–11921. [Google Scholar] [CrossRef] [Green Version]
  89. Li, R.; Ying, B.; Wei, Y.; Xing, H.; Qin, Y.; Li, D. Comparative evaluation of Sr-incorporated calcium phosphate and calcium silicate as bioactive osteogenesis coating orthopedics applications. Colloids Surf. A Physicochem. Eng. Asp. 2020, 600, 124834. [Google Scholar] [CrossRef]
  90. Li, B.; Xia, X.; Guo, M.; Jiang, Y.; Li, Y.; Zhang, Z.; Liu, S.; Li, H.; Liang, C.; Wang, H. Biological and antibacterial properties of the micro-nanostructured hydroxyapatite/chitosan coating on titanium. Sci. Rep. 2019, 9, 1–10. [Google Scholar] [CrossRef] [Green Version]
  91. Hussein, M.A.; Ankah, N.K.; Kumar, A.M.; Azeem, M.A.; Saravanan, S.; Sorour, A.A.; Al Aqeeli, N. Mechanical, biocorrosion, and antibacterial properties of nanocrystalline TiN coating for orthopedic applications. Ceram. Int. 2020, 46, 18573–18583. [Google Scholar] [CrossRef]
  92. Sun, Y.S.; Huang, H.H. Biphasic calcium phosphates/tantalum pentoxide hybrid layer and its effects on corrosion resistance and biocompatibility of titanium surface for orthopedic implant applications. J. Alloy. Compd. 2018, 743, 99–107. [Google Scholar] [CrossRef]
  93. Cui, W.; Qin, G.; Duan, J.; Wang, H. A graded nano-TiN coating on biomedical Ti alloy: Low friction coefficient, good bonding and biocompatibility. Mater. Sci. Eng. C 2017, 71, 520–528. [Google Scholar] [CrossRef]
  94. Cao, X.-Y.; Tian, N.; Dong, X.; Cheng, C.-K. Implant Coating Manufactured by Micro-Arc Oxidation and Dip Coating in Resorbable Polylactide for Antimicrobial Applications in Orthopedics. Coatings 2019, 9, 284. [Google Scholar] [CrossRef] [Green Version]
  95. Moriche, R.; Beltrán, A.M.; Begines, B.; Rodríguez-Ortiz, J.A.; Alcudia, A.; Torres, Y. Influence of the porosity and type of bioglass on the micro-mechanical and bioactive behavior of coated porous titanium substrates. J. Non. Cryst. Solids 2021, 551, 120436. [Google Scholar] [CrossRef]
  96. Torres, Y.; Begines, B.; Beltrán, A.M.; Boccaccini, A.R. Deposition of bioactive gelatin coatings on porous titanium: Influence of processing parameters, size and pore morphology. Surf. Coat. Technol. 2021, 421, 127366. [Google Scholar] [CrossRef]
  97. Gaviria, J.; Alcudia, A.; Begines, B.; Beltrán, A.M.; Villarraga, J.; Moriche, R.; Rodríguez-Ortiz, J.A.; Torres, Y. Synthesis and deposition of silver nanoparticles on porous titanium substrates for biomedical applications. Surf. Coat. Technol. 2021, 406, 126667. [Google Scholar] [CrossRef]
  98. Gaviria, J.; Alcudia, A.; Begines, B.; Beltrán, A.M.; Rodríguez-ortiz, J.A.; Trueba, P.; Villarraga, J.; Torres, Y. Biofunctionalization of porous ti substrates coated with ag nanoparticles for potential antibacterial behavior. Metals 2021, 11, 692. [Google Scholar] [CrossRef]
  99. Beltrán, A.M.; Alcudia, A.; Begines, B.; Rodríguez-Ortiz, J.A.; Torres, Y. Porous titanium substrates coated with a bilayer of bioactive glasses. J. Non. Cryst. Solids 2020, 544. [Google Scholar] [CrossRef]
  100. Beltrán, A.M.; Begines, B.; Alcudia, A.; Rodríguez-Ortiz, J.A.; Torres, Y. Biofunctional and Tribomechanical Behavior of Porous Titanium Substrates Coated with a Bioactive Glass Bilayer (45S5-1393). ACS Appl. Mater. Interfaces 2020, 12, 30170–30180. [Google Scholar] [CrossRef]
  101. Singh, A.; Singh, G.; Chawla, V. Characterization of Vacuum Plasma Sprayed Reinforced Hydroxyapatite Coatings on Ti–6Al–4V alloy. Trans. Indian Inst. Met. 2017, 70, 2609–2628. [Google Scholar] [CrossRef]
  102. Liu, X.; Li, M.; Zhu, Y.; Yeung, K.W.K.; Chu, P.K.; Wu, S. The modulation of stem cell behaviors by functionalized nanoceramic coatings on Ti-based implants. Bioact. Mater. 2016, 1, 65–76. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  103. Hu, C.; Aindow, M.; Wei, M. Focused ion beam sectioning studies of biomimetic hydroxyapatite coatings on Ti-6Al-4V substrates. Surf. Coat. Technol. 2017, 313, 255–262. [Google Scholar] [CrossRef]
  104. Bucur, A.I.; Linul, E.; Taranu, B.O. Hydroxyapatite coatings on Ti substrates by simultaneous precipitation and electrodeposition. Appl. Surf. Sci. 2020, 527, 146820. [Google Scholar] [CrossRef]
  105. Pillai, R.S.; Frasnelli, M.; Sglavo, V.M. HA/β-TCP plasma sprayed coatings on Ti substrate for biomedical applications. Ceram. Int. 2018, 44, 1328–1333. [Google Scholar] [CrossRef]
  106. Behera, R.R.; Das, A.; Hasan, A.; Pamu, D.; Pandey, L.M.; Sankar, M.R. Deposition of biphasic calcium phosphate film on laser surface textured Ti–6Al–4V and its effect on different biological properties for orthopedic applications. J. Alloy. Compd. 2020, 842, 155683. [Google Scholar] [CrossRef]
  107. Shi, Y.Y.; Li, M.; Liu, Q.; Jia, Z.J.; Xu, X.C.; Cheng, Y.; Zheng, Y.F. Electrophoretic deposition of graphene oxide reinforced chitosan–hydroxyapatite nanocomposite coatings on Ti substrate. J. Mater. Sci. Mater. Med. 2016, 27, 1–13. [Google Scholar] [CrossRef]
  108. Göncü, Y.; Geçgin, M.; Bakan, F.; Ay, N. Electrophoretic deposition of hydroxyapatite-hexagonal boron nitride composite coatings on Ti substrate. Mater. Sci. Eng. C 2017, 79, 343–353. [Google Scholar] [CrossRef]
  109. Yu, J.M.; Choe, H.C. Mg-containing hydroxyapatite coatings on Ti-6Al-4V alloy for dental materials. Appl. Surf. Sci. 2018, 432, 294–299. [Google Scholar] [CrossRef]
  110. Hu, C.; Yu, L.; Wei, M. Sectioning studies of biomimetic collagen-hydroxyapatite coatings on Ti-6Al-4V substrates using focused ion beam. Appl. Surf. Sci. 2018, 444, 590–597. [Google Scholar] [CrossRef]
  111. Singh, S.; Singh, G.; Bala, N. Electrophoretic deposition of hydroxyapatite-iron oxide-chitosan composite coatings on Ti–13Nb–13Zr alloy for biomedical applications. Thin Solid Film. 2020, 697, 137801. [Google Scholar] [CrossRef]
  112. Lu, R.J.; Wang, X.; He, H.X.; Ling-Ling, E.; Li, Y.; Zhang, G.L.; Li, C.J.; Ning, C.Y.; Liu, H.C. Tantalum-incorporated hydroxyapatite coating on titanium implants: Its mechanical and in vitro osteogenic properties. J. Mater. Sci. Mater. Med. 2019, 30, 1–14. [Google Scholar] [CrossRef]
  113. Dikici, B.; Niinomi, M.; Topuz, M.; Koc, S.G.; Nakai, M. Synthesis of biphasic calcium phosphate (BCP) coatings on β‒type titanium alloys reinforced with rutile-TiO2 compounds: Adhesion resistance and in-vitro corrosion. J. Sol-Gel Sci. Technol. 2018, 87, 713–724. [Google Scholar] [CrossRef]
  114. Singh, G.; Singh, H.; Sidhu, B.S. Characterization and corrosion resistance of plasma sprayed HA and HA-SiO2 coatings on Ti-6Al-4V. Surf. Coat. Technol. 2013, 228, 242–247. [Google Scholar] [CrossRef]
  115. Wang, X.; Li, B.; Zhou, L.; Ma, J.; Zhang, X.; Li, H.; Liang, C.; Liu, S.; Wang, H. Influence of surface structures on biocompatibility of TiO2/HA coatings prepared by MAO. Mater. Chem. Phys. 2018, 215, 339–345. [Google Scholar] [CrossRef]
  116. Quirama, A.; Echavarría, A.M.; Meza, J.M.; Osorio, J.; Bejarano G., G. Improvement of the mechanical behavior of the calcium phosphate coatings deposited onto Ti6Al4V alloy using an intermediate TiN/TiO2 bilayer. Vacuum 2017, 146, 22–30. [Google Scholar] [CrossRef]
  117. Robertson, S.F.; Bandyopadhyay, A.; Bose, S. Titania nanotube interface to increase adhesion strength of hydroxyapatite sol-gel coatings on Ti-6Al-4V for orthopedic applications. Surf. Coat. Technol. 2019, 372, 140–147. [Google Scholar] [CrossRef]
  118. Yi, P.; Peng, L.; Huang, J. Multilayered TiAlN films on Ti6Al4V alloy for biomedical applications by closed field unbalanced magnetron sputter ion plating process. Mater. Sci. Eng. C 2016, 59, 669–676. [Google Scholar] [CrossRef]
  119. Marques, D.M.; Oliveira, V.d.C.; Souza, M.T.; Zanotto, E.D.; Issa, J.P.M.; Watanabe, E. Biomaterials for orthopedics: Anti-biofilm activity of a new bioactive glass coating on titanium implants. Biofouling 2020, 36, 234–244. [Google Scholar] [CrossRef]
  120. Tüten, N.; Canadinc, D.; Motallebzadeh, A.; Bal, B. Microstructure and tribological properties of TiTaHfNbZr high entropy alloy coatings deposited on Ti–6Al–4V substrates. Intermetallics 2019, 105, 99–106. [Google Scholar] [CrossRef]
  121. Wang, J.; Ma, J.; Huang, W.; Wang, L.; He, H.; Liu, C. The investigation of the structures and tribological properties of F-DLC coatings deposited on Ti-6Al-4V alloys. Surf. Coat. Technol. 2017, 316, 22–29. [Google Scholar] [CrossRef]
  122. Heise, S.; Wirth, T.; Höhlinger, M.; Hernández, Y.T.; Ortiz, J.A.R.; Wagener, V.; Virtanen, S.; Boccaccini, A.R. Electrophoretic deposition of chitosan/bioactive glass/silica coatings on stainless steel and WE43 Mg alloy substrates. Surf. Coat. Technol. 2018, 344, 553–563. [Google Scholar] [CrossRef]
  123. Rehman, M.A.U.; Munawar, M.A.; Schubert, D.W.; Boccaccini, A.R. Electrophoretic deposition of chitosan/gelatin/bioactive glass composite coatings on 316L stainless steel: A design of experiment study. Surf. Coat. Technol. 2019, 358, 976–986. [Google Scholar] [CrossRef]
  124. Zarghami, V.; Ghorbani, M.; Pooshang Bagheri, K.; Shokrgozar, M.A. Prolongation of bactericidal efficiency of chitosan—Bioactive glass coating by drug controlled release. Prog. Org. Coat. 2019, 139, 105440. [Google Scholar] [CrossRef]
  125. Ur Rehman, M.A.; Bastan, F.E.; Nawaz, A.; Nawaz, Q.; Wadood, A. Electrophoretic deposition of PEEK/bioactive glass composite coatings on stainless steel for orthopedic applications: An optimization for in vitro bioactivity and adhesion strength. Int. J. Adv. Manuf. Technol. 2020, 108, 1849–1862. [Google Scholar] [CrossRef]
  126. Kawaguchi, K.; Iijima, M.; Endo, K.; Mizoguchi, I. Electrophoretic Deposition as a New Bioactive Glass Coating Process for Orthodontic Stainless Steel. Coatings 2017, 7, 199. [Google Scholar] [CrossRef] [Green Version]
  127. Rivera, L.R.; Cochis, A.; Biser, S.; Canciani, E.; Ferraris, S.; Rimondini, L.; Boccaccini, A.R. Antibacterial, pro-angiogenic and pro-osteointegrative zein-bioactive glass/copper based coatings for implantable stainless steel aimed at bone healing. Bioact. Mater. 2021, 6, 1479–1490. [Google Scholar] [CrossRef]
  128. Kawaguchi, K.; Iijima, M.; Muguruma, T.; Endo, K.; Mizoguchi, I. Effects of bioactive glass coating by electrophoretic deposition on esthetical, bending, and frictional performance of orthodontic stainless steel wire. Dent. Mater. J. 2020, 39, 593–600. [Google Scholar] [CrossRef]
  129. Oliver, J.; Anne, N.; Su, Y.; Lu, X.; Kuo, P.H.; Du, J.; Zhu, D. Bioactive glass coatings on metallic implants for biomedical applications. Bioact. Mater. 2019, 4, 261–270. [Google Scholar] [CrossRef]
  130. López-Cuevas, J.; Rendón-Angeles, J.C.; Méndez-Nonell, J.; Barrientos-Rodríguez, H. In Vitro Bioactivity of AISI 316L Stainless Steel Coated with Hydroxyapatite-Seeded 58S Bioglass. MRS Adv. 2019, 4, 3133–3142. [Google Scholar] [CrossRef]
  131. Al-Rashidy, Z.M.; Farag, M.M.; Abdel Ghany, N.A.; Ibrahim, A.M.; Abdel-Fattah, W.I. Orthopaedic bioactive glass/chitosan composites coated 316L stainless steel by green electrophoretic co-deposition. Surf. Coat. Technol. 2018, 334, 479–490. [Google Scholar] [CrossRef]
  132. Rezaei, A.; Golenji, R.B.; Alipour, F.; Hadavi, M.M.; Mobasherpour, I. Hydroxyapatite/hydroxyapatite-magnesium double-layer coatings as potential candidates for surface modification of 316 LVM stainless steel implants. Ceram. Int. 2020, 46, 25374–25381. [Google Scholar] [CrossRef]
  133. Balestriere, M.A.; Schuhladen, K.; Herrera Seitz, K.; Boccaccini, A.R.; Cere, S.M.; Ballarre, J. Sol-gel coatings incorporating borosilicate bioactive glass enhance anti corrosive and surface performance of stainless steel implants. J. Electroanal. Chem. 2020, 876, 114735. [Google Scholar] [CrossRef]
  134. Hosseini, M.R.; Ahangari, M.; Johar, M.H.; Allahkaram, S.R. Optimization of nano HA-SiC coating on AISI 316L medical grade stainless steel via electrophoretic deposition. Mater. Lett. 2021, 285, 129097. [Google Scholar] [CrossRef]
  135. Omar, S.A.; Ballarre, J.; Ceré, S.M. Protection and functionalization of AISI 316 L stainless steel for orthopedic implants: Hybrid coating and sol gel glasses by spray to promote bioactivity. Electrochim. Acta 2016, 203, 309–315. [Google Scholar] [CrossRef]
  136. Tumer, D.; Gungorurler, M.; Havitcioglu, H.; Arman, Y. Investigation of effective coating of the Tie6Ale4V alloy and 316L stainless steel with graphene or carbon nanotubes with finite element methods. J. Mater. Res. Technol. 2020, 9, 15880–15893. [Google Scholar] [CrossRef]
  137. Vafa, E.; Bazargan-Lari, R.; Bahrololoom, M.E. Electrophoretic deposition of polyvinyl alcohol/natural chitosan/bioactive glass composite coatings on 316L stainless steel for biomedical application. Prog. Org. Coat. 2021, 151, 106059. [Google Scholar] [CrossRef]
  138. Basiaga, M.; Walke, W.; Kajzer, W.; Sambok-Kiełbowicz, A.; Szewczenko, J.; Simka, W.; Szindler, M.; Ziębowicz, B.; Lubenets, V. Atomic layer deposited ZnO films on stainless steel for biomedical applications. Arch. Civ. Mech. Eng. 2021, 21, 1. [Google Scholar] [CrossRef]
  139. Khamseh, S.; Alibakhshi, E.; Ramezanzadeh, B.; Ganjaee Sari, M. A tailored pulsed substrate bias voltage deposited (a-C: Nb) thin-film coating on GTD-450 stainless steel: Enhancing mechanical and corrosion protection characteristics. Chem. Eng. J. 2021, 404, 126490. [Google Scholar] [CrossRef]
  140. Aqib, R.; Kiani, S.; Bano, S.; Wadood, A.; Ur Rehman, M.A. Ag–Sr doped mesoporous bioactive glass nanoparticles loaded chitosan/gelatin coating for orthopedic implants. Int. J. Appl. Ceram. Technol. 2021, 18, 544–562. [Google Scholar] [CrossRef]
  141. Kaliaraj, G.S.; Thukkaram, S.; Alagarsamy, K.; Kirubaharan, A.M.K.; Paul, L.K.; Abraham, L.; Vishwakarma, V.; Sagadevan, S. Silver-calcia stabilized zirconia nanocomposite coated medical grade stainless steel as potential bioimplants. Surf. Interfaces 2021, 24, 101086. [Google Scholar] [CrossRef]
  142. Lohberger, B.; Stuendl, N.; Glaenzer, D.; Rinner, B.; Donohue, N.; Lichtenegger, H.C.; Ploszczanski, L.; Leithner, A. CoCrMo surface modifications affect biocompatibility, adhesion, and inflammation in human osteoblasts. Sci. Rep. 2020, 10, 1–8. [Google Scholar] [CrossRef]
  143. Döring, J.; Crackau, M.; Nestler, C.; Welzel, F.; Bertrand, J.; Lohmann, C.H. Characteristics of different cathodic arc deposition coatings on CoCrMo for biomedical applications. J. Mech. Behav. Biomed. Mater. 2019, 97, 212–221. [Google Scholar] [CrossRef]
  144. Ayu, H.M.; Izman, S.; Daud, R.; Krishnamurithy, G.; Shah, A.; Tomadi, S.H.; Salwani, M.S. Surface Modification on CoCrMo Alloy to Improve the Adhesion Strength of Hydroxyapatite Coating. In Procedia Engineering; Elsevier Ltd.: Amsterdam, The Netherlands, 2017; Volume 184, pp. 399–408. [Google Scholar]
  145. Romonţi, D.C.; Iskra, J.; Bele, M.; Demetrescu, I.; Milošev, I. Elaboration and characterization of fluorohydroxyapatite and fluoroapatite sol-gel coatings on CoCrMo alloy. J. Alloy. Compd. 2016, 665, 355–364. [Google Scholar] [CrossRef]
  146. Shiri, S.; Zhang, C.; Odeshi, A.; Yang, Q. Growth and characterization of tantalum multilayer thin films on CoCrMo alloy for orthopedic implant applications. Thin Solid Film. 2018, 645, 405–408. [Google Scholar] [CrossRef]
  147. Tsai, C.E.; Hung, J.; Hu, Y.; Wang, D.Y.; Pilliar, R.M.; Wang, R. Improving fretting corrosion resistance of CoCrMo alloy with TiSiN and ZrN coatings for orthopedic applications. J. Mech. Behav. Biomed. Mater. 2021, 114, 104233. [Google Scholar] [CrossRef]
  148. Zhang, Q.; Li, K.; Yan, J.; Wang, Z.; Wu, Q.; Bi, L.; Yang, M.; Han, Y. Graphene coating on the surface of CoCrMo alloy enhances the adhesion and proliferation of bone marrow mesenchymal stem cells. Biochem. Biophys. Res. Commun. 2018, 497, 1011–1017. [Google Scholar] [CrossRef]
  149. Ragone, V.; Canciani, E.; Biffi, C.A.; D’Ambrosi, R.; Sanvito, R.; Dellavia, C.; Galliera, E. CoCrMo alloys ions release behavior by TiNbN coating: An in vitro study. Biomed. Microdevices 2019, 21, 1–9. [Google Scholar] [CrossRef]
  150. Jakovljević, S.; Alar, V.; Ivanković, A. Electrochemical Behaviour of PACVD TiN-Coated CoCrMo Medical Alloy. Metals 2017, 7, 231. [Google Scholar] [CrossRef] [Green Version]
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Figure 1. The weight percentage of (a) β TCP (b) HA of a film with different thicknesses. Reprinted with permission from [86].
Figure 1. The weight percentage of (a) β TCP (b) HA of a film with different thicknesses. Reprinted with permission from [86].
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Figure 2. Cell adhesion and cell proliferation response (a) Number of adhered cells (b) cell proliferation. (* indicates statistical significance < 0.05 vs. TC4, & indicates statistical significance < 0.05 vs. Si-Sr@TC4). Reprinted with permission from [89].
Figure 2. Cell adhesion and cell proliferation response (a) Number of adhered cells (b) cell proliferation. (* indicates statistical significance < 0.05 vs. TC4, & indicates statistical significance < 0.05 vs. Si-Sr@TC4). Reprinted with permission from [89].
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Figure 3. Bacterial viable cell count (a) gram -ve bacteria (E. coli) (b) gram +ve bacteria (B. Subtilis). Reprinted with permission from [91].
Figure 3. Bacterial viable cell count (a) gram -ve bacteria (E. coli) (b) gram +ve bacteria (B. Subtilis). Reprinted with permission from [91].
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Figure 4. Corrosion behavior of Ti, Ta2O5, and BCPs/Ta2O5/Ti samples (a) Corrosion current density (b) ion concentration. (* indicates statistical significance p < 0.05). Reprinted with permission from [92].
Figure 4. Corrosion behavior of Ti, Ta2O5, and BCPs/Ta2O5/Ti samples (a) Corrosion current density (b) ion concentration. (* indicates statistical significance p < 0.05). Reprinted with permission from [92].
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Figure 5. (a) Load-displacement response of graded coating (b) COF vs. sliding time response. Reprinted with permission from [93].
Figure 5. (a) Load-displacement response of graded coating (b) COF vs. sliding time response. Reprinted with permission from [93].
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Figure 6. (a) Adhesion performance of various coating groups (b) degradation rate of coating of PLC coating. Adapted with permission from [94].
Figure 6. (a) Adhesion performance of various coating groups (b) degradation rate of coating of PLC coating. Adapted with permission from [94].
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Figure 7. (a) pH change (b) Ca ion concentration in SBF solution for different compositions of BG coatings on stainless steel. Reprinted with permission from [131].
Figure 7. (a) pH change (b) Ca ion concentration in SBF solution for different compositions of BG coatings on stainless steel. Reprinted with permission from [131].
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Figure 8. (a) Corrosion potential (b) Cell viability. Reprinted with permission from [132].
Figure 8. (a) Corrosion potential (b) Cell viability. Reprinted with permission from [132].
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Figure 9. (a) Cell viability (p < 0.01 **; p < 0.001 ***) (b) CytoTox LDH release. Adapted with permission from [142].
Figure 9. (a) Cell viability (p < 0.01 **; p < 0.001 ***) (b) CytoTox LDH release. Adapted with permission from [142].
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Figure 10. Friction results for different coated materials. Reprinted with permission from [143].
Figure 10. Friction results for different coated materials. Reprinted with permission from [143].
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Table
Table 1. Most common biomaterials for orthopedic implants.
Table 1. Most common biomaterials for orthopedic implants.
MaterialUsesAdvantagesDisadvantagesChallenges
Titanium alloys
[31,32]		Femoral hip stems
Shoulder stems
Fasteners, nails, rods, screws, wires
Fracture fixation plates
Pedicle screws and rods for spines		Lightweight
Less biological response
Biocompatible
High corrosion resistance		Poor bending ductility
Poor wear resistance
Expensive
High modulus		Biodegradable
Biological inertness
Antibacterial
Stability in mechanical properties
Wear reduction
Stainless steel alloys
[33,34]		Plates, screws, pins, wires
Sliding hip screws
Flexible and intramedullary nails
Cerclage cables		Widely available
High ductility
Accepted toughness
Accepted biocompatibility		Very high modulus
Allergic reactivity
Stress shielding effect
Poor wear resistance		Corrosion resistance
Wear reduction
Biological inertness
Cobalt-chrome Molybdenum
[35]		Bearing surface in metal
Plates and wires
Shorter-term implants		Long term
biocompatibility
High corrosion resistance
High wear resistance
High impact durability		Stress shielding effect
Poor machinability
Biological toxicity due to release of Ni		Wear reduction
Metallic fretting
Biological inertness
Polyethylene/UHMWPE
[36,37,38]		Bearing surfacesBiocompatibility
Wear resistance		Wear debris
Lower mechanical properties
Joint infections		Fatigue life
Alumina/
Zirconia composites
[39,40]		Bearing surfacesHigh smoothness
Biocompatibility		High fracture rateBrittleness
Table
Table 2. Most common coating techniques for implant material coatings.
Table 2. Most common coating techniques for implant material coatings.
Coating MethodMethod ClassificationAdvantagesDisadvantages
Physical vapor deposition (PVD)
[44,45,46,47,48,49,50,51,52,53]		Cathodic arc deposition
RF magnetron sputtering
DC reactive magnetron sputtering
Close field magnetron sputter ion plating
Cathode plasma immersion ion implantation deposition
Planar magnetron sputtering
Electron beam evaporation		Coat complex geometries with ease
High dense
High purity
Increased wear resistance		Delamination
Expensive
Time-consuming
Chemical vapor deposition (CVD)
[54,55,56]		Atomic layer deposition
Plasma assisted chemical vapor deposition		Coat complex geometries with ease
Increased wear resistance		Delamination
Expensive
Electrochemical deposition
[57,58,59,60,61,62,63]		Electrophoretic co-depositionLow temperature
Increased wear resistance		Expensive
Thin layer
Sol-gel
[64,65,66,67,68,69,70]		Dip coatingCoat complex geometries
High homogeneity
High purity
Low temperature
Low cost		Low wear resistance
Low permeability
Delamination
Low mechanical stability
Thin layer
Plasma spraying
[71,72,73,74,75]		------Low cost
Rapid deposition rate
Long life span		Low adhesion
Cracks
Microstructure change
Micro arc oxidation
[76,77,78,79,80]		-----Low cost
Eco friendly
Multifunctional coatings		Porosities formation
Cracks
Delamination
Table
Table 3. Summary of results for coatings on titanium surface.
Table 3. Summary of results for coatings on titanium surface.
Ref.Coating MaterialThicknessCoating MethodBiocompatibility/Antibacterial PropertiesCorrosion/Degradation BehaviorMechanical ResultsTribological Results
[86]Biphasic calcium phosphate (BCP)1000 nmRF magnetron sputteringwt.% of HA—86.76%
Enhancement in wt.% of apatite layer show bioactivity		------Microhardness—455 HV (140%)Roughness—153 nm (168%)
Higher scratch resistance
[92]BCP/Ta2O51 µm/700 nmElectrochemical deposition/Hydration condensationSpherical apatite layer formation in immersion test show bioactivityCorrosion current density—0.2 µA/cm2 (5.7%)-----------
[94]Micro-arc oxidation & Polylactide-L-lactide-CO-ε-caprolactone (PLC)5.4 µmMicro-arc oxidation/dip coating-----Mass loss—24.8%Adhesion strength—13 MPa
Load to failure—4000 N		-----
[118]Ti-TiN-TiAlN2.52 µmClose field magnetron sputter ion plating-----Corrosion current density—1.74 × 10−3 µA/cm2 (7.5%)
Hardness—37.2 GPa (775%)
Elastic modulus—409 GPa (339%)
Adhesion strength—48 N		COF—0.23 (50%)
Wear rate—3.73 × 10−5 mm3/Nm (7.53%)
[93]TiN5.8 µmDC reactive magnetron sputteringRelative growth rate of cells—+90%
OD values and Hemolysis ratio show good biocompatibility.		------Elastic modulus—281 GPa
Hardness—0.8 GPa
Bonding Force/Adhesion strength—80 N		COF—0.2
Wear rate—0.62 × 10−6 mm3/Nm
Wear track depth—0.34 µm
[91]TiN5 µmCathodic arc-physical depositionAntibacterial inhabitation efficiency rates—138.2%Corrosion current density—3.21 × 10−2 µA/cm2 (0.35%)Hardness—38.3 GPa (726%)
Elastic modulus—358 GPa
Indentation depth—600 nm (47.69%)		Roughness—13 nm
COF—0.448
Contact stress at failure—2.23 GPa
[89]Sr incorporate calcium phosphate5–8 µmMicro-arc oxidationBetter cell adhesion and cell proliferation---------------
[119]Bioactive glass (BGF18) Similar cell adhesion
Thicker biofilm growth for coated (128%)		----------Surface roughness—3.96 nm (1320%)
[120]TiTaHfNbZr-----RF magnetron sputtering----------Hardness—3.46 GPa
Elastic modulus—115 GPa		Roughness—2.78 nm (327%)
COF—0.15
[121]Flourine doped diamond-like-carbon/Si1.6 µmCathode plasma immersion ion implantation deposition-----------Hardness—18.3 GPa
Elastic modulus—163 GPa		Roughness—7.8 nm
COF—0.11
Table
Table 4. Summary of results for stainless steel.
Table 4. Summary of results for stainless steel.
Ref.Coating MaterialThicknessCoating MethodBiocompatibility/Antibacterial PropertiesCorrosion/Degradation BehaviorMechanical ResultsTribological Results
[131]Bioactive glass-chitosan143 µmElectrophoretic co-deposition-----pH—7.4–7.9
Ca ion concentration—20 × 10−2 mmm/h
Corrosion current density—20.93 µA/cm2
Corrosion rate—5.02		-----Roughness—170 µm (2.9%)
[133]Bioactive glass/silane2/0.6 µmDip coatingOptical density—0.2Corrosion current density—154 µA/cm2Show no detachment
[134]HA-3SiC45 µmElectrophoretic deposition-----Corrosion potential—0.041Elastic modulus—728 MPa
Bonding strength—1.61 MPa		-----
[135]Bioactive glass/silane1.2 µmDip coating------Improvement in corrosion resistance but show degradation in immersion test------------
[132]HA-10wt.%Mg100 µmPlasma sprayingCell viability—96.7% (132%)
Distribution of calcium phosphate show bioactivity		Mg ion concentration—71 ppm
Corrosion potential—−0.250
Corrosion current density—0.12 µA/cm2		------------
[136]Carbon nano tubes (CNTs)80 µmFEM--------Static stress—87.574 MPa (181%)------
[137]Chitosan-20 Polyvinyl alcohol (PVA)-BG---Electrophoretic depositionHA forming ability show best bioactivityCorrosion potential—−0.7265Optimum adhesive strength for 20 wt. % PVA coating------
[138]ZNO220 nmAtomic layer deposition Corrosion potential—−0.131
Corrosion current density—0.04 µA/cm2		Indenter load to failure—0.85 NSurface roughness—0.40 µm
[139]Amorphous carbon: Niobium2 µmPlanar magnetron sputtering Enhancement in corrosion protectionHardness—16.5 GPa
Young modulus—44 GPa		COF—0.10
[140]5 Ag-Sr-Chitosan-Gelatin---Electrophoretic depositionSuitable proliferation of osteoblast cells
Antibacterial		-----Suitable adhesion strength-----
[141]Ag-CaSZ nanocomposites---E-beam evaporationHemocompatible
Calcite precipitation		Improved corrosion resistance-----------
Table
Table 5. Summary of results for CoCrMo alloys.
Table 5. Summary of results for CoCrMo alloys.
Ref.Coating MaterialThicknessCoating MethodBiocompatibility/Antibacterial PropertiesCorrosion/Degradation BehaviorMechanical ResultsTribological Results
[144]HA/oxide12.73/51.03 µmSol-gel dip coating--------Adhesion strength—8.63 N
Increases by increasing sintering temperature.		----
[142]TiN5.5 µmPhysical vapor depositionOsteoblast viability—145.6%-----Tensile strength—22 MPa
Shear strength—20 MPa		Roughness—50 µm
[145]Fluorohydroxyapatite6.22 µmSol-gel procedureCorrosion potential—0.264 V
Corrosion density—3.7 × 10−3 µA/cm2		----Show high adhesionRoughness—0.477 µm
[146]Tantalum1.5 µmMagnetron sputtering----------Multilayered Ta film shows best adhesion----
[147]TiSIN1.89 µmCathodic arc evaporation Reduction in fretting volume—1000 times
Reduction in Co Ion release—90%		Elastic modulus—396 GPa
Hardness—41.6 GPa
Residual stress—−8.00 GPa
Critical load—0.329 N		Roughness—0.0406 µm
[147]ZrN2.37 µmCathodic arc evaporation Reduction in fretting volume—10 times
Reduction in Co Ion release—90%		Elastic modulus—409 GPa
Hardness—29.3 GPa
Residual stress—−8.00 GPa
Critical load—0.175 N		Roughness—0.0134 µm
[148]Graphene5.76 µmChemical vapor depositionImproved cell proliferation-----Adhesion strength—1152 µN----
[143]TiN1.7 µmCathodic arc evaporation Hardness—30 GPa
Penetration modulus—514 GPa
Critical load—10 N		Roughness—0.0045 µm
COF—0.094
Wear rate—4 × 10−15 m3/mN
[143]Diamond-like carbon0.7 µmCathodic arc evaporation----------Hardness—74 GPa
Penetration modulus—680 GPa
Critical load—3 N		Roughness—0.0285 µm
COF—0.023
[149]TiNbN3–6 µmPhysical vapor depositionViability—above 100%Reduction in Co/Cr/Mo ion released—80.1/62.5/48%-----------
[150]TiN2 µmPlasma assisted chemical vapor deposition-----Corrosion rate—0.793 µm/y------------
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Hussain, M.; Askari Rizvi, S.H.; Abbas, N.; Sajjad, U.; Shad, M.R.; Badshah, M.A.; Malik, A.I. Recent Developments in Coatings for Orthopedic Metallic Implants. Coatings 2021, 11, 791. https://doi.org/10.3390/coatings11070791

AMA Style

Hussain M, Askari Rizvi SH, Abbas N, Sajjad U, Shad MR, Badshah MA, Malik AI. Recent Developments in Coatings for Orthopedic Metallic Implants. Coatings. 2021; 11(7):791. https://doi.org/10.3390/coatings11070791

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Hussain, Muzamil, Syed Hasan Askari Rizvi, Naseem Abbas, Uzair Sajjad, Muhammad Rizwan Shad, Mohsin Ali Badshah, and Asif Iqbal Malik. 2021. "Recent Developments in Coatings for Orthopedic Metallic Implants" Coatings 11, no. 7: 791. https://doi.org/10.3390/coatings11070791

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