Polymers

Research

12 pages, 3409 KiB

Open AccessArticle

Highly Biocompatible Apigenin-Loaded Silk Fibroin Nanospheres: Preparation, Characterization, and Anti-Breast-Cancer Activity

by Weikun Qu, Peng Ji, Xibin Han, Xianglong Wang, Yang Li and Jin Liu

Polymers 2023, 15(1), 23; https://doi.org/10.3390/polym15010023 - 21 Dec 2022

Cited by 5 | Viewed by 1574

Abstract

Breast cancer is among the most common fatal diseases among women. Low-toxicity apigenin (AGN) is of interest due to its good antitumor activity, but its clinical application is severely limited due to its poor water solubility and low bioavailability. An effective strategy to [...] Read more.

Breast cancer is among the most common fatal diseases among women. Low-toxicity apigenin (AGN) is of interest due to its good antitumor activity, but its clinical application is severely limited due to its poor water solubility and low bioavailability. An effective strategy to enhance the anti-breast-cancer activity of AGN is to develop it as a nanodelivery system. Silk fibroin (SF) is an ideal drug carrier with good biocompatibility, biodegradability, and a simple extraction process. This paper develops a novel and efficient apigenin-loaded silk fibroin nanodelivery system (SF-AGN) by nanoprecipitation with SF as a carrier. The system was characterized in terms of morphology, zeta potential, particle size, ultraviolet (UV), infrared (IR), and synchronous thermal analyses (TG-DSC), and the in vitro cytotoxicity and in vivo pharmacokinetics were examined. Finally, the chronic toxicity of SF-AGN in mice was studied. The SF-AGN nanodelivery system has good dispersibility, a hydrated particle size of 163.35 nm, a zeta potential of −18.5 mV, an average drug loading of 6.20%, and good thermal stability. MTT studies showed that SF-AGN significantly enhanced the inhibitory effect of AGN on 4T1 and MDA-MB-231 cells. Pharmacokinetic studies have demonstrated that SF-AGN can dramatically improve the bioavailability of AGN. The results of toxicity experiments showed that SF-AGN is biocompatible and does not alter normal tissues or organs. In sum, the SF-AGN nanodelivery system is a promising drug-delivery system for the clinical treatment of breast cancer. Full article

(This article belongs to the Special Issue Biomedical Modelling and Biomechanics of Polymer Materials)

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23 pages, 5062 KiB

Open AccessArticle

Stress Shielding and Bone Resorption of Press-Fit Polyether–Ether–Ketone (PEEK) Hip Prosthesis: A Sawbone Model Study

by Seyed Ataollah Naghavi, Churun Lin, Changning Sun, Maryam Tamaddon, Mariam Basiouny, Pilar Garcia-Souto, Stephen Taylor, Jia Hua, Dichen Li, Ling Wang and Chaozong Liu

Polymers 2022, 14(21), 4600; https://doi.org/10.3390/polym14214600 - 29 Oct 2022

Cited by 23 | Viewed by 6829

Abstract

Stress shielding secondary to bone resorption is one of the main causes of aseptic loosening, which limits the lifespan of the hip prostheses and increases the rates of revision surgery. This study proposes a low stiffness polyether–ether–ketone (PEEK) hip prostheses, produced by fused [...] Read more.

Stress shielding secondary to bone resorption is one of the main causes of aseptic loosening, which limits the lifespan of the hip prostheses and increases the rates of revision surgery. This study proposes a low stiffness polyether–ether–ketone (PEEK) hip prostheses, produced by fused deposition modelling to minimize the stress difference after the hip replacement. The stress shielding effect and the potential bone resorption of the PEEK implant was investigated through both experimental tests and FE simulation. A generic Ti6Al4V implant was incorporated in this study to allow fair comparison as control group. Attributed to the low stiffness, the proposed PEEK implant showed a more natural stress distribution, less stress shielding (by 104%), and loss in bone mass (by 72%) compared with the Ti6Al4V implant. The stiffness of the Ti6Al4V and the PEEK implant were measured through compression tests to be 2.76 kN/mm and 0.276 kN/mm. The factor of safety for the PEEK implant in both static and dynamic loading scenarios were obtained through simulation. Most of the regions in the PEEK implant were tested to be safe (FoS larger than 1) in terms of representing daily activities (2300 N), while the medial neck and distal restriction point of the implant attracts large von Mises stress 82 MPa and 76 MPa, respectively, and, thus, may possibly fail during intensive activities by yield and fatigue. Overall, considering the reduction in stress shielding and bone resorption in cortical bone, PEEK could be a promising material for the patient–specific femoral implants. Full article

(This article belongs to the Special Issue Biomedical Modelling and Biomechanics of Polymer Materials)

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14 pages, 2019 KiB

Open AccessArticle

The Preliminary Assessment of New Biomaterials Necessitates a Comparison of Direct and Indirect Cytotoxicity Methodological Approaches

by Milena Chraniuk, Mirosława Panasiuk, Lilit Hovhannisyan, Sabina Żołędowska, Dawid Nidzworski, Lidia Ciołek, Anna Woźniak, Zbigniew Jaegermann, Monika Biernat and Beata Gromadzka

Polymers 2022, 14(21), 4522; https://doi.org/10.3390/polym14214522 - 25 Oct 2022

Cited by 12 | Viewed by 2378

Abstract

Background: Cytotoxicity testing is a primary method to establish the safety of biomaterials, e.g., biocomposites. Biomaterials involve a wide range of medical materials, which are usually solid materials and are used in bone regeneration, cardiology, or dermatology. Current advancements in science and technology [...] Read more.

Background: Cytotoxicity testing is a primary method to establish the safety of biomaterials, e.g., biocomposites. Biomaterials involve a wide range of medical materials, which are usually solid materials and are used in bone regeneration, cardiology, or dermatology. Current advancements in science and technology provide several standard cytotoxicity testing methods that are sufficiently sensitive to detect various levels of cellular toxicity, i.e., from low to high. The aim was to compare the direct and indirect methodology described in the ISO guidelines UNE-EN ISO 10993-5:2009 Part 5. Methods: Cell proliferation was measured using WST-1 assay, and cytotoxicity was measured using LDH test kit. Results: The results indicate that the molecular surface of biomaterials have impact on the cytotoxicity and proliferation profile. Based on these results, we confirm that the indirect method does not provide a clear picture of the cell condition after the exposure to the surface, and moreover, cannot provide complete results about the effects of the material. Conclusions: Comparison of both methods shows that it is pivotal to investigate biomaterials at the very early stages using both indirect and direct methods to access the influence of the released toxins and surface of the material on the cell condition. Full article

(This article belongs to the Special Issue Biomedical Modelling and Biomechanics of Polymer Materials)

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14 pages, 1836 KiB

Open AccessArticle

Structural Exploration on Palmitoyltransferase DHHC3 from Homo sapiens

by Meng Tang, Ying Xia, Taoran Xiao, Ruiyu Cao, Yu Cao and Bo Ouyang

Polymers 2022, 14(15), 3013; https://doi.org/10.3390/polym14153013 - 26 Jul 2022

Cited by 1 | Viewed by 1960

Abstract

DHHC3 belongs to a family of DHHC palmitoyltransferase, which catalyzes the S-palmitoylation of target proteins by attaching a fatty acyl group to a cysteine. Recently, DHHC3 has been demonstrated to be a promising antitumor target in cancer therapeutics. However, the detailed structure and [...] Read more.

DHHC3 belongs to a family of DHHC palmitoyltransferase, which catalyzes the S-palmitoylation of target proteins by attaching a fatty acyl group to a cysteine. Recently, DHHC3 has been demonstrated to be a promising antitumor target in cancer therapeutics. However, the detailed structure and catalysis mechanism of DHHC3 remain elusive, considering its sequence diversity from the DHHC homologs with known crystal structures. Here, we described the expression and purification of human DHHC3 (hDHHC3) and truncated hDHHC3 with the flexible N-terminal domain (NTD) removed. Purified hDHHC3 proteins were used under various conditions for protein crystallization. LAMTOR1, one of the interacting proteins of hDHHC3 to facilitate the crystallization, was further identified by mass spectrometry and co-immunoprecipitation assay. The structural exploration using cryogenic electronic microscopy (cryo-EM) on the inactive hDHHS3 mutant showed a typical sideview of membrane proteins. These results provide a preliminary guidance for the structural determination of DHHC3. Full article

(This article belongs to the Special Issue Biomedical Modelling and Biomechanics of Polymer Materials)

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14 pages, 5570 KiB

Open AccessArticle

Effects of Periodontal Splints on Biomechanical Behaviors in Compromised Periodontal Tissues and Cement Layer: 3D Finite Element Analysis

by Yuchen Liu, Ming Fang, Ruifeng Zhao, Hengyan Liu, Min Tian, Sheng Zhong and Shizhu Bai

Polymers 2022, 14(14), 2835; https://doi.org/10.3390/polym14142835 - 12 Jul 2022

Cited by 2 | Viewed by 3035

Abstract

Background: In this study, we evaluated the effect of periodontal splints made from different materials on the stress distributions in compromised periodontal tissues and cement layers, using a computer simulation of mastication. Methods: Twenty-five 3D models were created for a segment of mandibular [...] Read more.

Background: In this study, we evaluated the effect of periodontal splints made from different materials on the stress distributions in compromised periodontal tissues and cement layers, using a computer simulation of mastication. Methods: Twenty-five 3D models were created for a segment of mandibular teeth with different periodontal splints bilaterally extended to the canines. The models were divided into five groups according to the different materials and thicknesses (mm) of the splints: the non-splinted group, PEEK 0.7 group, PEEK 1.0 group, FRC group, and titanium group. Each group was subdivided based on five bone loss levels. Tooth 41 of each model was subjected to vertical and oblique (θ = 45°) static loads of 100 N, respectively, onto the incisal edge. The von Mises stresses and maximum principal stress were analyzed using Abaqus software. Results: Oblique loading resulted in higher stresses on periodontal tissues, cement layers, and splints than those caused by vertical loading. The lower the supporting bone level, the greater the stress difference between the splinted groups and the non-splinted group. In model 133,331, with severe bone loss, the maximum von Mises stress values on the alveolar bone in tooth 41 under oblique loading dramatically decreased from 406.4 MPa in the non-splinted group to 28.62 MPa in the PEEK group and to 9.59 MPa in the titanium group. The four splinted groups presented similar stress distributions in periodontal tissues. The lowest stress level on the splint was observed in the PEEK 0.7 group, and the highest stress level was transferred to the cement layer in this group. Stress concentrations were primarily exhibited at the connectors near the load-carrying area. Conclusions: The tested splinted groups were all effective in distributing the loads on periodontal tissues around splinted teeth with similar patterns. Using splinting materials with low elastic moduli reduced the stress concentration at the splint connectors, whereas the tensile stress concentration was increased in the cement layer. Thus, the use of adhesive cement with a higher elastic modulus is recommended when applying less rigid PEEK splints. Full article

(This article belongs to the Special Issue Biomedical Modelling and Biomechanics of Polymer Materials)

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12 pages, 2922 KiB

Open AccessArticle

Cryogenic Coaxial Printing for 3D Shell/Core Tissue Engineering Scaffold with Polymeric Shell and Drug-Loaded Core

by Tianqi Liu, Bo Yang, Wenqing Tian, Xianglin Zhang and Bin Wu

Polymers 2022, 14(9), 1722; https://doi.org/10.3390/polym14091722 - 22 Apr 2022

Cited by 7 | Viewed by 2375

Abstract

For decades, coaxial printing has been widely applied in 3D tissue engineering scaffold fabrication. However, there are few reports regarding polymeric materials application in shell production due to fabrication constraints. In this study, a combination of cryogenic printing and coaxial printing aims to [...] Read more.

For decades, coaxial printing has been widely applied in 3D tissue engineering scaffold fabrication. However, there are few reports regarding polymeric materials application in shell production due to fabrication constraints. In this study, a combination of cryogenic printing and coaxial printing aims to approach the challenge. Polycaprolactone (PCL) and sodium alginate (SA) were selected as the representative shell and core materials to test the feasibility of the coaxial cryogenic printing by optimizing key parameters, including working temperature, air pressure, PCL, and SA concentration. According to the optical and SEM images, the SA core contracts a string inside the PCL shell, illustrating the shell/core structure of the 3D coaxial PCL/SA scaffolds. Besides, the shell/core 3D scaffold possesses a 38.39 MPa Young’s modulus in mechanical tests; the PCL shell could retain at least 8 h in 5 mol/L HCl solution, leading to a fabricated drug-loaded PCL/SA shell/core “responsive” to acidic pH. In summary, coaxial cryogenic printing was developed to fabricate 3D scaffolds with a PCL/SA shell/core scaffold, broadening the material range of coaxial printing and providing promising applications in drug release. Full article

(This article belongs to the Special Issue Biomedical Modelling and Biomechanics of Polymer Materials)

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Review

Jump to: Research, Other

23 pages, 428 KiB

Open AccessReview

Recent Advances in the Application of Natural and Synthetic Polymer-Based Scaffolds in Musculoskeletal Regeneration

by Bing Ye, Bin Wu, Yanlin Su, Tingfang Sun and Xiaodong Guo

Polymers 2022, 14(21), 4566; https://doi.org/10.3390/polym14214566 - 27 Oct 2022

Cited by 22 | Viewed by 2392

Abstract

The musculoskeletal system plays a critical role in providing the physical scaffold and movement to the mammalian body. Musculoskeletal disorders severely affect mobility and quality of life and pose a heavy burden to society. This new field of musculoskeletal tissue engineering has great [...] Read more.

The musculoskeletal system plays a critical role in providing the physical scaffold and movement to the mammalian body. Musculoskeletal disorders severely affect mobility and quality of life and pose a heavy burden to society. This new field of musculoskeletal tissue engineering has great potential as an alternative approach to treating large musculoskeletal defects. Natural and synthetic polymers are widely used in musculoskeletal tissue engineering owing to their good biocompatibility and biodegradability. Even more promising is the use of natural and synthetic polymer composites, as well as the combination of polymers and inorganic materials, to repair musculoskeletal tissue. Therefore, this review summarizes the progress of polymer-based scaffolds for applications of musculoskeletal tissue engineering and briefly discusses the challenges and future perspectives. Full article

(This article belongs to the Special Issue Biomedical Modelling and Biomechanics of Polymer Materials)

Other

Jump to: Research, Review

22 pages, 1624 KiB

Open AccessSystematic Review

Endoscopic Delivery of Polymers Reduces Delayed Bleeding after Gastric Endoscopic Submucosal Dissection: A Systematic Review and Meta-Analysis

by Youli Chen, Xinyan Zhao, Dongke Wang, Xinghuang Liu, Jie Chen, Jun Song, Tao Bai and Xiaohua Hou

Polymers 2022, 14(12), 2387; https://doi.org/10.3390/polym14122387 - 13 Jun 2022

Cited by 5 | Viewed by 2396

Abstract

New endoscopic approaches for the prevention of delayed bleeding (DB) after gastric endoscopic submucosal dissection (ESD) have been reported in recent years, and endoscopic delivery of biodegradable polymers for iatrogenic ulcer hemostasis and coverage has emerged as one of the most promising techniques [...] Read more.

New endoscopic approaches for the prevention of delayed bleeding (DB) after gastric endoscopic submucosal dissection (ESD) have been reported in recent years, and endoscopic delivery of biodegradable polymers for iatrogenic ulcer hemostasis and coverage has emerged as one of the most promising techniques for post-ESD management. However, the comparative efficacy of these techniques remains uncertain. We performed a systematic search of multiple databases up to May 2022 to identify studies reporting DB rates as outcomes in patients undergoing gastric ESD who were treated with subsequent endoscopic management, including endoscopic closure (clip-based methods and suturing), PGA sheet tissue shielding, and hemostatic powder/gel spray (including polymeric sealants and other adhesives). The risk ratios (RRs) of delayed bleeding in treatment groups and control groups were pooled, and the Bayesian framework was used to perform a network meta-analysis (NMA). Among these studies, 16 head-to-head comparisons that covered 2742 lesions were included in the NMA. Tissue shielding using PGA sheets significantly reduced the risk of DB by nearly two thirds in high-risk patients, while hemostatic spray systems, primarily polymer-based, reduced DB in low-risk patients nine-fold. Researchers should recognize the essential role of polymers in the management of ESD-induced ulcers, and develop and validate clinical application strategies for promising materials. Full article

(This article belongs to the Special Issue Biomedical Modelling and Biomechanics of Polymer Materials)

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