Résumé
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.
Résumé
In this study, an attempt was made to develop bi-functional constructs serving both as scaffolds and potential delivery systems for application in neural tissue engineering. The constructs were prepared in two steps. In the first step, the bulks of poly (L-lactic acid) (PLLA) in 1, 4-dioxane/water (87:13) were fabricated using liquid-liquid thermally induced phase separation technique. In the next step, the prepared bulks were coated with chitosan nanoparticles produced by two different techniques of ultrasonication and ionic gelation by grafting-coating technique. In ultrasonication technique, the chitosan solution (2 mg/mL) in acetic acid/sodium acetate buffer (90:10) was irradiated by an ultrasound generator at 20 kHz and power output of 750 W for 100 s. In ionic gelation technique, the tripolyphosphate in water solution (1 mg/mL) was added to the same chitosan solution. The physicochemical properties of the products were characterized by Scanning Electron Microscopy, Attenuated Total Reflection Fourier Transform-Infrared, liquid displacement technique, contact angle measurement, compressive and tensile tests, as well as zeta potential and particle size analysis using dynamic light scattering. Moreover, the cell proliferation and attachment on the scaffolds were evaluated through human glioblastoma cell line (U-87 MG) and human neuroblastoma cell line [BE (2)-C] culture respectively. The results showed that the samples coated with chitosan nanoparticles prepared by ultrasonication possessed enhanced hydrophilicity, biodegradation and cytocompatibility compared with pure PLLA and PLLA coated with chitosan nanoparticles prepared by ionic gelation. This study suggests successful nanoparticles-scaffold systems which can act simultaneously as potential delivery systems and tissue engineering scaffolds.