Advanced Hydrogels: Preparation, Property, and Biomedical Application

A special issue of Gels (ISSN 2310-2861). This special issue belongs to the section "Gel Processing and Engineering".

Deadline for manuscript submissions: closed (31 March 2023) | Viewed by 56687

Special Issue Editors


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Guest Editor
College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
Interests: nonfouling materials; nanomedicine

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Guest Editor
Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
Interests: biolubrication; biomaterials; hydrogels
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
Interests: biomaterials; wound repair

Special Issue Information

Dear Colleagues,

Hydrogels are physically or chemically crosslinked three-dimensional networks. Due to the variety monomer and crosslinker types, these hydrogels exhibit extraordinary properties, including high water content, porosity, and flexibility, leading to their extensive use in biomedical applications. They are of great interest in biocompatible implant devices, biosensors, drug delivery systems, wound care, and many other applications.

In this Special Issue, we welcome original research articles and comprehensive reviews with topics addressing but not limited to the key findings and contributions on advanced hydrogels, including preparation methods, characterization, and biomedical applications.

Note: If you are unable to meet the current submission deadline, please consider our Volume II:
Advanced Hydrogels: Preparation, Property and Biomedical Application (2nd Edition)

Prof. Dr. Shengfu Chen
Prof. Dr. Weifeng Lin
Prof. Dr. Jiang Wu
Guest Editors

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Keywords

  • zwitterionic hydrogels
  • nanogels
  • composite hydrogels
  • double network hydrogels
  • antifouling
  • wound healing
  • lubrication
  • mechanical properties
  • implants

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Published Papers (12 papers)

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Research

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19 pages, 4521 KiB  
Article
Formulation Development and Evaluation of Indian Propolis Hydrogel for Wound Healing
by Harshad S. Kapare, Prabhanjan S. Giram, Sadhana S. Raut, Hemant K. Gaikwad and Ana Cláudia Paiva-Santos
Gels 2023, 9(5), 375; https://doi.org/10.3390/gels9050375 - 1 May 2023
Cited by 9 | Viewed by 3679
Abstract
Flavonoids and polyphenolic compounds play a key role in wound healing cycle modulation. Propolis, a natural bee product, has been widely reported as an enriched source of polyphenols and flavonoids as important chemical constituents and for its wound healing potential. The goal of [...] Read more.
Flavonoids and polyphenolic compounds play a key role in wound healing cycle modulation. Propolis, a natural bee product, has been widely reported as an enriched source of polyphenols and flavonoids as important chemical constituents and for its wound healing potential. The goal of this study was to develop and characterize a propolis-based polyvinyl alcohol (PVA) hydrogel composition with wound healing potential. To understand the impacts of critical material attributes and process parameters, formulation development was carried out using a design of experiment approach. A preliminary phytochemical analysis of Indian propolis extract showed the presence of flavonoids (23.61 ± 0.0452 mg equivalent of quercetin/g) and polyphenols (34.82 ± 0.0785 mg equivalent of gallic acid/g), both of which aid in wound healing and skin tissue regeneration. The pH, viscosity, and in vitro release of the hydrogel formulation were also studied. The burn wound healing model results revealed significant (p < 0.0001) wound contraction by propolis hydrogel (93.58 + 0.15%) with rapid re-epithelialization relative to 5% w/w povidone iodine ointment USP (Cipladine®) (95.39 + 0.16%). The excision wound healing model confirms significant (p < 0.0001) wound contraction by propolis hydrogel (91.45 + 0.29%) with accelerated re-epithelialization comparable to 5% w/w povidone iodine ointment USP (Cipladine®) (94.38 + 0.21%). The developed formulation offers promise for wound healing, which may be investigated further for clinical research. Full article
(This article belongs to the Special Issue Advanced Hydrogels: Preparation, Property, and Biomedical Application)
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12 pages, 5197 KiB  
Article
Silver-Composited Polydopamine Nanoparticles: Antibacterial and Antioxidant Potential in Nanocomposite Hydrogels
by Geun-Jin Song, Yeon-Su Choi, Hee-Sook Hwang and Chung-Sung Lee
Gels 2023, 9(3), 183; https://doi.org/10.3390/gels9030183 - 27 Feb 2023
Cited by 3 | Viewed by 2062
Abstract
(1) Background: Infections of pathogenic microorganisms can be life-threatening due to delayed healing or even worsening conditions in tissue engineering and regenerative medicine. The excessive presence of reactive oxygen species in damaged and infected tissues causes a negative inflammatory response, resulting in failed [...] Read more.
(1) Background: Infections of pathogenic microorganisms can be life-threatening due to delayed healing or even worsening conditions in tissue engineering and regenerative medicine. The excessive presence of reactive oxygen species in damaged and infected tissues causes a negative inflammatory response, resulting in failed healing. Thus, the development of hydrogels with antibacterial and antioxidant abilities for the treatment of infectious tissues is in high demand. (2) Methods: We herein describe the development of green-synthesized silver-composited polydopamine nanoparticles (AgNPs), which are fabricated by the self-assembly of dopamine as a reducing and antioxidant agent in the presence of silver ions. (3) Results: The facile and green-synthesized AgNPs have a nanoscale diameter with mostly spherical shapes, with various shapes coexisting. The particles are stable in an aqueous solution for up to 4 weeks. In addition, remarkable antibacterial activity against Gram-positive and -negative bacterial strains and antioxidant capabilities were evaluated by in vitro assays. When incorporated into biomaterial hydrogels at concentrations above 2 mg L−1, the hydrogels produced powerful antibacterial effects. (4) Conclusions: This study describes a biocompatible hydrogel with antibacterial and antioxidant activities from the introduction of facile and green-synthesized AgNPs as a safer tool for the treatment of damaged tissues. Full article
(This article belongs to the Special Issue Advanced Hydrogels: Preparation, Property, and Biomedical Application)
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11 pages, 2120 KiB  
Article
Bioinspired Oxidation-Resistant Catechol-like Sliding Ring Polyrotaxane Hydrogels
by M. Isabel Rial-Hermida, Dora C. S. Costa, Lan Jiang, João M. M. Rodrigues, Kohzo Ito and João F. Mano
Gels 2023, 9(2), 85; https://doi.org/10.3390/gels9020085 - 19 Jan 2023
Cited by 4 | Viewed by 2427
Abstract
Adaptable hydrogels have been used in the biomedical field to address several pathologies, especially those regarding tissue defects. Here, we describe unprecedented catechol-like functionalized polyrotaxane (PR) polymers able to form hydrogels. PR were functionalized with the incorporation of hydroxypyridinone (HOPO) moieties into the [...] Read more.
Adaptable hydrogels have been used in the biomedical field to address several pathologies, especially those regarding tissue defects. Here, we describe unprecedented catechol-like functionalized polyrotaxane (PR) polymers able to form hydrogels. PR were functionalized with the incorporation of hydroxypyridinone (HOPO) moieties into the polymer backbone, with a degree of substitution from 4 to 22%, depending on the PR type. The hydrogels form through the functionalized supramolecular systems when in contact with a Fe(III) solution. Despite the hydrogel formation being at physiological pH (7.4), the HOPO derivatives are extremely resistant to oxidation, unlike common catechols; consequently, they prevent the formation of quinones, which can lead to irreversible bounds within the matrix. The resulting hydrogels demonstrated properties lead to unique hydrogels with improved mechanical behavior obtained by metallic coordination crosslinking, due to the synergies of the sliding-ring PR and the non-covalent (reversible) catechol analogues. Following this strategy, we successfully developed innovative, cytocompatible, oxidative-resistant, and reversible crosslinked hydrogels, with the potential of being used as structural self-materials for a variety of applications, including in the biomedical field. Full article
(This article belongs to the Special Issue Advanced Hydrogels: Preparation, Property, and Biomedical Application)
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18 pages, 2778 KiB  
Article
Responsive Hyaluronic Acid–Ethylacrylamide Microgels Fabricated Using Microfluidics Technique
by Marcus Wanselius, Agnes Rodler, Sean S. Searle, Susanna Abrahmsén-Alami and Per Hansson
Gels 2022, 8(9), 588; https://doi.org/10.3390/gels8090588 - 15 Sep 2022
Cited by 4 | Viewed by 3820
Abstract
Volume changes of responsive microgels can probe interactions between polyelectrolytes and species of opposite charges such as peptides and proteins. We have investigated a microfluidics method to synthesize highly responsive, covalently crosslinked, hyaluronic acid microgels for such purposes. Sodium hyaluronate (HA), pre-modified with [...] Read more.
Volume changes of responsive microgels can probe interactions between polyelectrolytes and species of opposite charges such as peptides and proteins. We have investigated a microfluidics method to synthesize highly responsive, covalently crosslinked, hyaluronic acid microgels for such purposes. Sodium hyaluronate (HA), pre-modified with ethylacrylamide functionalities, was crosslinked in aqueous droplets created with a microfluidic technique. We varied the microgel properties by changing the degree of modification and concentration of HA in the reaction mixture. The degree of modification was determined by 1H NMR. Light microscopy was used to investigate the responsiveness of the microgels to osmotic stress in aqueous saline solutions by simultaneously monitoring individual microgel species in hydrodynamic traps. The permeability of the microgels to FITC-dextrans of molecular weights between 4 and 250 kDa was investigated using confocal laser scanning microscopy. The results show that the microgels were spherical with diameters between 100 and 500 µm and the responsivity tunable by changing the degree of modification and the HA concentration. Microgels were fully permeable to all investigated FITC-dextran probes. The partitioning to the microgel from an aqueous solution decreased with the increasing molecular weight of the probe, which is in qualitative agreement with theories of homogeneous gel networks. Full article
(This article belongs to the Special Issue Advanced Hydrogels: Preparation, Property, and Biomedical Application)
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16 pages, 5430 KiB  
Article
Synthesis and Characterization of Novel Patchouli Essential Oil Loaded Starch-Based Hydrogel
by H. P. S. Abdul Khalil, Syaifullah Muhammad, Esam Bashir Yahya, Lee Kar Mun Amanda, Suriani Abu Bakar, C. K. Abdullah, Abd Rahim Aiman, M. Marwan and Samsul Rizal
Gels 2022, 8(9), 536; https://doi.org/10.3390/gels8090536 - 26 Aug 2022
Cited by 8 | Viewed by 3113
Abstract
Starch hydrogels are highly available, biocompatible and biodegradable materials that have promising applications in medical and pharmaceutical industries. However, their applications are very limited due to their poor mechanical properties and fragility. Here, we investigated, for the first time, conventional corn and waxy [...] Read more.
Starch hydrogels are highly available, biocompatible and biodegradable materials that have promising applications in medical and pharmaceutical industries. However, their applications are very limited due to their poor mechanical properties and fragility. Here, we investigated, for the first time, conventional corn and waxy corn starch-based hydrogels for loading patchouli essential oil. The essential oil extracted by supercritical carbon dioxide with a yield reached 8.37 ± 1.2 wt.% (wet sample) at 80 °C temperature and 10 MPa pressure. Patchouli essential oil exhibited a 23 to 28 mm zone of inhibition against gram-positive and gram-negative bacteria. Waxy starch hydrogels had better properties in term of viscosity, water evaporation stability and the delivery of essential oil than conventional starch hydrogels. The viscosity and spreadability of a 6% waxy starch sample were 15,016 ± 59 cP and 4.02 ± 0.34 g·cm/s, respectively, compared with those of conventional starch hydrogel (13,008 ± 29 cP and 4.59 ± 0.88 g·cm/s). Waxy starch-based hydrogels also provided slower in vitro biodegradation behavior and sustained release of essential oil compared with conventional starch hydrogels. All the samples were biocompatible and non-cytotoxic to fibroblast cells; the addition of patchouli essential oil enhances the proliferation of the cells. The enhanced viscosity, good antibacterial and improved biocompatibility results of prepared hydrogels confirm their suitability for wound healing applications. Full article
(This article belongs to the Special Issue Advanced Hydrogels: Preparation, Property, and Biomedical Application)
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17 pages, 2995 KiB  
Article
Dextrin-Based Nanohydrogels for Rokitamycin Prolonged Topical Delivery
by Maria Tannous, Silvia Lucia Appleton, Gjylije Hoti, Fabrizio Caldera, Monica Argenziano, Yousef Khazaei Monfared, Adrián Matencio, Francesco Trotta and Roberta Cavalli
Gels 2022, 8(8), 490; https://doi.org/10.3390/gels8080490 - 8 Aug 2022
Viewed by 2226
Abstract
Macrolides are widely used antibiotics with a broad spectrum of activity. The development of drug carriers to deliver this type of antibiotics has attracted much research. The present study aims at developing new swellable dextrin-based nanohydrogels for the topical delivery of rokitamycin, as [...] Read more.
Macrolides are widely used antibiotics with a broad spectrum of activity. The development of drug carriers to deliver this type of antibiotics has attracted much research. The present study aims at developing new swellable dextrin-based nanohydrogels for the topical delivery of rokitamycin, as model macrolide. Rokitamycin is a synthetic analogous of macrolides with advantageous characteristics as far as bacterial uptake and post-antibiotic effect are concerned. It is also indicated for the treatment of severe infections caused by Acanthamoeba and for topical infections. The nanohydrogels have been prepared from two types of cross-linked polymers obtained by using β-cyclodextrin or Linecaps® was provided by the Roquette Italia SPA (Cassano Spinola, Al, Italy) as building blocks. The cross-linked polymers have been then formulated into aqueous nanosuspensions refined and tuned to achieve the incorporation of the drug. Cross-linked β-cyclodextrin (β-CD) and Linecaps® (LC) polymers formed dextrin-based nanohydrogels with high swelling degree and mucoadhesion capability. Rokitamycin was loaded into the nanohydrogels displaying an average size around 200 nm with negative surface charge. In vitro kinetic profiles of free and loaded drug in nanohydrogels were compared at two pH levels. Interestingly, a sustained and controlled release was obtained at skin pH level due to the high degree of swelling and a pH responsiveness possibly. The results collected suggest that these nanohydrogels are promising for the delivery of rokitamycin and may pave the way for the topical delivery of other macrolide antibiotics. Full article
(This article belongs to the Special Issue Advanced Hydrogels: Preparation, Property, and Biomedical Application)
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17 pages, 2603 KiB  
Article
Thermosensitive Injectable Hydrogels for Intra-Articular Delivery of Etanercept for the Treatment of Osteoarthritis
by Jomarien García-Couce, Timo Schomann, Chih Kit Chung, Ivo Que, Carla Jorquera-Cordero, Gastón Fuentes, Amisel Almirall, Alan Chan and Luis J. Cruz
Gels 2022, 8(8), 488; https://doi.org/10.3390/gels8080488 - 5 Aug 2022
Cited by 13 | Viewed by 2963
Abstract
The intra-articular administration of drugs has attracted great interest in recent decades for the treatment of osteoarthritis. The use of modified drugs has also attracted interest in recent years because their intra-articular administration has demonstrated encouraging results. The objective of this work was [...] Read more.
The intra-articular administration of drugs has attracted great interest in recent decades for the treatment of osteoarthritis. The use of modified drugs has also attracted interest in recent years because their intra-articular administration has demonstrated encouraging results. The objective of this work was to prepare injectable-thermosensitive hydrogels for the intra-articular administration of Etanercept (ETA), an inhibitor of tumor necrosis factor-α. Hydrogels were prepared from the physical mixture of chitosan and Pluronic F127 with β-glycerolphosphate (BGP). Adding β-glycerolphosphate to the system reduced the gelation time and also modified the morphology of the resulting material. In vitro studies were carried out to determine the cytocompatibility of the prepared hydrogels for the human chondrocyte line C28/I2. The in vitro release study showed that the incorporation of BGP into the system markedly modified the release of ETA. In the in vivo studies, it was verified that the hydrogels remained inside the implantation site in the joint until the end of the study. Furthermore, ETA was highly concentrated in the blood of the study mice 48 h after the loaded material was injected. Histological investigation of osteoarthritic knees showed that the material promotes cartilage recovery in osteoarthritic mice. The results demonstrate the potential of ETA-loaded injectable hydrogels for the localized treatment of joints. Full article
(This article belongs to the Special Issue Advanced Hydrogels: Preparation, Property, and Biomedical Application)
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15 pages, 24477 KiB  
Article
Construction and Tribological Properties of Biomimetic Cartilage-Lubricating Hydrogels
by Qiuyi Chen, Sa Liu, Zhongrun Yuan, Hai Yang, Renjian Xie and Li Ren
Gels 2022, 8(7), 415; https://doi.org/10.3390/gels8070415 - 1 Jul 2022
Cited by 12 | Viewed by 3136
Abstract
Articular cartilage provides ultralow friction to maintain the physiological function of the knee joint, which arises from the hierarchical complex composed of hyaluronic acid, phospholipids, and lubricin, covering the cartilage surface as boundary lubrication layers. Cartilage-lubricating polymers (HA/PA and HA/PM) mimicking this complex [...] Read more.
Articular cartilage provides ultralow friction to maintain the physiological function of the knee joint, which arises from the hierarchical complex composed of hyaluronic acid, phospholipids, and lubricin, covering the cartilage surface as boundary lubrication layers. Cartilage-lubricating polymers (HA/PA and HA/PM) mimicking this complex have been demonstrated to restore the lubrication of cartilage via hydration lubrication, thus contributing to the treatment of early osteoarthritis (OA) in vivo. Here, biomimetic cartilage-lubricating hydrogels (HPX/PVA) were constructed by blending HA/PA and HA/PM (HPX) with polyvinyl alcohol (PVA) to improve the boundary lubrication and wear properties, so that the obtained hydrogels may offer a solution to the main drawbacks of PVA hydrogels used as cartilage implants. The HPX/PVA hydrogels exhibited good physicochemical and mechanical properties through hydrogen-bonding interactions, and showed lower friction and wear under the boundary lubrication and fluid film lubrication mechanisms, which remained when the hydrogels were rehydrated. Our strategy may provide new insights into exploring cartilage-inspired lubricating hydrogels. Full article
(This article belongs to the Special Issue Advanced Hydrogels: Preparation, Property, and Biomedical Application)
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21 pages, 9496 KiB  
Article
Highly Responsive Chitosan-Co-Poly (MAA) Nanomatrices through Cross-Linking Polymerization for Solubility Improvement
by Anam Saleem, Naveed Akhtar, Muhammad Usman Minhas, Arshad Mahmood, Kifayat Ullah Khan and Orva Abdullah
Gels 2022, 8(3), 196; https://doi.org/10.3390/gels8030196 - 21 Mar 2022
Cited by 5 | Viewed by 2698
Abstract
In this study, we report the highly responsive chitosan-based chemically cross-linked nanomatrices, a nano-version of hydrogels developed through modified polymerization reaction for solubility improvement of poorly soluble drug simvastatin. The developed nanomatrices were characterized for solubilization efficiency, swelling studies, sol-gel analysis, in vitro [...] Read more.
In this study, we report the highly responsive chitosan-based chemically cross-linked nanomatrices, a nano-version of hydrogels developed through modified polymerization reaction for solubility improvement of poorly soluble drug simvastatin. The developed nanomatrices were characterized for solubilization efficiency, swelling studies, sol-gel analysis, in vitro drug release studies, DSC, FTIR, XRD, SEM, particle size analysis, and stability studies. An in vivo acute toxicity study was conducted on female Winstor rats, the result of which endorsed the safety and biocompatibility of the system. A porous and fluffy structure was observed under SEM analysis, which supports the great swelling tendency of the system that further governs the in vitro drug release. Zeta sizer analyzed the particle size in the range of 227.8 ± 17.8 nm. Nano sizing and grafting of hydrophilic excipients to the nanomatrices system explains this shift of trend towards the enhancement of solubilization efficiency, and, furthermore, the XRD results confirmed the amorphous nature of the system. FTIR and DSC analysis confirmed the successful grafting and stability to the system. The developed nanomatrices enhanced the release characteristics and solubility of simvastatin significantly and could be an effective technique for solubility and bioavailability enhancement of other BCS class-II drugs. Due to enhanced solubility, efficient method of preparation, excellent physico-chemical features, and rapid and high dissolution and bio-compatibility, the developed nanomatrices may be a promising approach for oral delivery of hydrophobic drugs. Full article
(This article belongs to the Special Issue Advanced Hydrogels: Preparation, Property, and Biomedical Application)
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Review

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22 pages, 2023 KiB  
Review
Recent Advances in Hydrogels for the Diagnosis and Treatment of Dry Eye Disease
by Qiaoqiao Li, Yifeng Cao and Ping Wang
Gels 2022, 8(12), 816; https://doi.org/10.3390/gels8120816 - 11 Dec 2022
Cited by 11 | Viewed by 8457
Abstract
Dry eye disease (DED) is the most common clinical ocular surface disease. Given its multifactorial etiology, no consensus has been reached on the diagnosis criteria for dry eye disease. Topical drug administration remains the mainstay of treatment but is limited to the rapid [...] Read more.
Dry eye disease (DED) is the most common clinical ocular surface disease. Given its multifactorial etiology, no consensus has been reached on the diagnosis criteria for dry eye disease. Topical drug administration remains the mainstay of treatment but is limited to the rapid clearance from the eye surface. To address these problems, hydrogel-based materials were designed to detect biomarkers or act as drug delivery systems by taking advantage of their good biocompatibility, excellent physical and mechanical properties, and long-term implant stability. Biosensors prepared using biocompatible hydrogels can be sensitive in diagnosing DED, and the designed hydrogels can also improve the drug bioavailability and retention time for more effective and long-term treatment. This review summarizes recent advances in the use of hydrogels for diagnosing and treating dry eye, aiming to provide a novel reference for the eventual clinical translation of hydrogels in the context of dry eye disease. Full article
(This article belongs to the Special Issue Advanced Hydrogels: Preparation, Property, and Biomedical Application)
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20 pages, 12908 KiB  
Review
Recent Advances in Mechanical Reinforcement of Zwitterionic Hydrogels
by Weifeng Lin, Xinyue Wei, Sihang Liu, Juan Zhang, Tian Yang and Shengfu Chen
Gels 2022, 8(9), 580; https://doi.org/10.3390/gels8090580 - 13 Sep 2022
Cited by 4 | Viewed by 3664
Abstract
As a nonspecific protein adsorption material, a strong hydration layer provides zwitterionic hydrogels with excellent application potential while weakening the interaction between zwitterionic units, leading to poor mechanical properties. The unique anti-polyelectrolyte effect in ionic solution further restricts the application value due to [...] Read more.
As a nonspecific protein adsorption material, a strong hydration layer provides zwitterionic hydrogels with excellent application potential while weakening the interaction between zwitterionic units, leading to poor mechanical properties. The unique anti-polyelectrolyte effect in ionic solution further restricts the application value due to the worsening mechanical strength. To overcome the limitations of zwitterionic hydrogels that can only be used in scenarios that do not require mechanical properties, several methods for strengthening mechanical properties based on enhancing intermolecular interaction forces and polymer network structure design have been extensively studied. Here, we review the works on preparing tough zwitterionic hydrogel. Based on the spatial and molecular structure design, tough zwitterionic hydrogels have been considered as an important candidate for advanced biomedical and soft ionotronic devices. Full article
(This article belongs to the Special Issue Advanced Hydrogels: Preparation, Property, and Biomedical Application)
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55 pages, 4757 KiB  
Review
Natural Hydrogel-Based Bio-Inks for 3D Bioprinting in Tissue Engineering: A Review
by Ahmed Fatimi, Oseweuba Valentine Okoro, Daria Podstawczyk, Julia Siminska-Stanny and Amin Shavandi
Gels 2022, 8(3), 179; https://doi.org/10.3390/gels8030179 - 14 Mar 2022
Cited by 130 | Viewed by 16976
Abstract
Three-dimensional (3D) printing is well acknowledged to constitute an important technology in tissue engineering, largely due to the increasing global demand for organ replacement and tissue regeneration. In 3D bioprinting, which is a step ahead of 3D biomaterial printing, the ink employed is [...] Read more.
Three-dimensional (3D) printing is well acknowledged to constitute an important technology in tissue engineering, largely due to the increasing global demand for organ replacement and tissue regeneration. In 3D bioprinting, which is a step ahead of 3D biomaterial printing, the ink employed is impregnated with cells, without compromising ink printability. This allows for immediate scaffold cellularization and generation of complex structures. The use of cell-laden inks or bio-inks provides the opportunity for enhanced cell differentiation for organ fabrication and regeneration. Recognizing the importance of such bio-inks, the current study comprehensively explores the state of the art of the utilization of bio-inks based on natural polymers (biopolymers), such as cellulose, agarose, alginate, decellularized matrix, in 3D bioprinting. Discussions regarding progress in bioprinting, techniques and approaches employed in the bioprinting of natural polymers, and limitations and prospects concerning future trends in human-scale tissue and organ fabrication are also presented. Full article
(This article belongs to the Special Issue Advanced Hydrogels: Preparation, Property, and Biomedical Application)
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