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Objective:For severe skin defects which are deep to dermis, engineered skin with epidermis and dermis (bilayered) is required. Based on the success of engineering epidermis with GT/PCL electrospun membranes, our study was to investigate whether this membrane could be also used for engineering bilayered skin graft.Methods:From 2013 to 2019, we first prepared three GT/PCL electrospun membranes with different proportion (70∶30; 50∶50; 30∶70) in our laboratory; the biocompatibility of the membrane was evaluated in vitro by seeding fibroblasts or keratinocytes on the membranes. Then the outcome of GT/PCL membranes repairing skin defects in the nude mouse was investigated.Results:Cell attachment and proliferation were significantly improved with increase of gelatin. Histological analyses showed that bilayered skin engineered with GT/PCL (70∶30) group could form relatively better structure after 3 weeks of cultivation in vitro. Further in vivo transplantation studies revealed that scaffolds were not degraded in all three groups, indicating that these materials were not suitable for engineering bilayered skin although they had good biocompatibility.Conclusions:The higher gelatin membranes possess better biocompatibility. Further in vivo transplantation studies reveal that bilayered skin engineered with GT/PCL membranes is able to repair skin defects in the nude mouse.
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BACKGROUND: Bionic porous scaffolds used in bone tissue engineering requires extracellular matrix-like nanofibrous and connected macroporous structure to effectively support cell implantation, adhesion, proliferation and other behaviors, and promote tissue regeneration. OBJECTIVE: To summarize the research progress in nanorfibrous macroporous scaffold preparation technology for tissue engineering based on the latest relevant research trends. METHODS: The first author searched Web of Science, CNKI and Baidu academic databases to retrieve papers published from 2000 to 2019 with the search terms “bone tissue engineering, nanofibrous, macroporous, scaffolds” in English and Chinese, respectively. Finally, 58 articles were included in result analysis. RESULTS AND CONCLUSION: The scaffolds with nanofibrous structures are fabricated using three strategies, including electrospinning, thermally induced phase separation, and self-assembly process. However, bone scaffold fabricated by a single strategy failed to provide interconnected macropores to simulate the microenvironment in the body, which was necessary for cell migration, growth, differentiation, proliferation, and tissue and organ regeneration. Therefore, it is now of great practical and scientific significance to develop macroporous nanofibrous scaffold using a combination of several strategies. Three-dimensional printing technique can provide precise structure and enables the customization of the internal structure and external shape of the scaffold, which promotes the development of bone tissue engineering technique.
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Normal wound healing is a very complicated process. As the wound covering, the dressing can protect the wound, accelerate the healing process and prevent infection during wound healing. Chitosan-based nanofibers have shown great prospect in biomedical dressings due to their unique biological and physicochemical properties. In this paper, the characteristics, materials, application and evaluation of chitosan-based electrospun nanofiber dressings are reviewed, and its application prospects are also prospected.
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A titanium implant surface when coated with biodegradable, highly porous, osteogenic nanofibrous coating has shown enhanced intrinsic osteoinductive and osteoconductive properties. This coating mimics extracellular matrix resulting in differentiation of stem cells present in the peri-implant niche to osteoblast and hence results in enhanced osseointegration of the implant. The osteogenic nanofibrous coating (ONFC) consists of poly-caprolactone, gelatin, nano-sized hydroxyapatite, dexamethasone, ascorbic acid and beta-glycerophosphate. ONFC exhibits optimum mechanical properties to support mesenchymal stem cells and steer their osteogenic differentiation. ONFC was subjected to various characterization tests like scanning electron microscopy, Fourier-transform infrared spectroscopy, x-ray diffractometry, thermal degradation, biomineralization, mechanical properties, wettability and proliferation assay. In pre-clinical animal trials, the coated implant showed enhanced new bone formation when placed in the tibia of rabbit. This novel approach toward implant bone integration holds significant promise for its easy and economical coating thus marking the beginning of new era of electrospun osteogenic nanofibrous coated bone implants.
Subject(s)
Animals , Ascorbic Acid , Dexamethasone , Durapatite , Extracellular Matrix , Gelatin , Mesenchymal Stem Cells , Microscopy, Electron, Scanning , Osseointegration , Osteoblasts , Osteogenesis , Spectrum Analysis , Stem Cells , Tibia , Titanium , WettabilityABSTRACT
Objective: To explore the effect of silk fibroin/poly( L-lactic acid-co-e-caprolactone) [SF/P(LLA-CL)] nanofibrous scaffold on tendon-bone healing of rabbits.
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Objective To investigate the sustained release of BSA from chitosan-OREC/BSA films coated mats in vitro.Methods The negatively charged cellulose acetate (CA) fibrous mats were modified with multilayers of the positively charged chitosan or chitosan-OREC intercalated composites and the negatively charged bovine serum albumin (BSA) via electrostatic layer-by-layer (LBL) self-assembly technique.The adsorption and rinsing steps were repeated until the desired number of deposition bilayers was obtained.The in vitro BSA encapsulation and release experiments demonstrated that OREC could affect the degree of protein loading capacity and release ficiency of the LBL films coating.Results In the pH-gradient release assay,only a small amount of BSA was released from the mats in 1 h.As the time increased,the release rate of BSA of all the samples gradually went up to the maximum data within 8 h.For the samples with identical number of bilayers and record time,obvious increasing of the release amount could be seen in pH 7.4,in comparison with pH 1.2.Besides,doubling bilayers film-coated mats generally.Meanwhile,it was slightly distinguishable between 5 and 5.5 as well as 10 and 10.5 bilayers (t=0.651～ 1.324,P＞0.05).Interestingly,it could be seen that protein release of the chitosan-OREC/BSA films coated mats remarkably increased compared with that of chitosan/BSA films coated mats(t=2.264～ 2.305,P＜0.05).Conclusion The release of protein in the initial time could be controlled by adjusting the number of deposition bilayers,the outmost layer and the composition of coating bilayers.