Collagen/bioactive glass/chitosan composite scaffolds / 中国组织工程研究

BACKGROUND:Col agen/bioactive glass composite materials possess excellent osteogenic potential and biocompatibility, but its application in bone tissue engineering is limited by mechanical property and degradation. OBJECTIVE:To construct col agen/bioactive glass/chitosan composite scaffolds with good mechanical property, anti-degradation ability and bone repair property. METHODS:Bioactive glass/col agen composite scaffolds with chitosan as dispersant were prepared by lyophylization. Fourier transform infrared spectroscopy, scanning electron microscope, X-ray diffraction, and dynamic biomechanical testing were used to characterize the structure and properties of the composite scaffolds. RESULTS AND CONCLUSION:Results show that charge-attractions in pre-prepared bioactive glass/chitosan solution increased the homogeneity of bioactive glass dispersed in col agen gel and the compressive modulus and strength increased significantly due to the homogeneity and intermolecular interactions between chitosan and col agen. The enzymatic degradation rate and mineralization activity in the simulated body fluid were also lower because of a high degree of embedment of bioactive glass in col agen/chitosan matrix, and entanglement of col agen in chitosan at molecular level, which decreased the exposure of bioactive glass to the simulated body fluid, and col agen to enzyme solution.

Determination of ethyl pyruvate in chitosan nanoparticles by reversed-phase high-performance liquid chromatography / 中国组织工程研究

BACKGROUND:Research on ethyl pyruvate detection methods is reported rarely, and moreover, literature about reversed-phase high-performance liquid chromatography (RP-HPLC) for detection of ethyl pyruvate is less. OBJECTIVE:To establish an RP-HPLC method for determination of ethyl pyruvate in ethyl pyruvate-chitosan nanoparticles. METHODS: The chromatographic analysis was performed on a ZORBAX Eclipse XDB-C18 column (4.6 mm× 150 mm, 5μm) at 25℃, with the mixture of acetonitrile and water (40:60, V/V) as the mobile phase at the flow rate of 1 mL/min. The determination wavelength wasset at 210 nm and the injection volume was 20 μL. RESULTS AND CONCLUSION: The peak of ethyl pyruvate and the peaks of auxiliary materials and solvent were separated wel. The linear rang of ethyl pyruvate was 1-100 mg/L (r=0.999 6). The relative standard deviation of both the intra-and inter-day precision was less than 3% for low-, moderate-, and high-concentration ethyl pyruvate. The relative standard deviation of reproducibility test and stability test was 1.25% and 1.3%, respectively. Sample average recovery rates were (91.5±1.0)%, (3.5±0.2)%, (94.4±0.4)%, respectively. Encapsulation efficiency of samples were (87.2±0.22)%, (90.5±0.15)%, (91.1±0.17)%, respectively. The relative standard deviation of different sample content were 0.9%, 0.5%, 0.3%, respectively. The RP-HPLC method for determination of ethyl pyruvate is sensitive, accurate and highly specific with wide linear range and high sample average recovery.

Application of tracing technique of labeling bone marrow mesenchymal stem cells with green fluorescent protein in tissue-engineered bone construction in vitro / 生物医学工程学杂志

This study was designed to label rat bone marrow mesenchymal stem cells (rBMSCs) with humanized renillar green fluorescent protein (hrGFP) for exploring the detectable effects of hrGFP on the construction of tissue-engineered bone in vitro. The hrGFP expression plasmid was packed into lentivirus by 293FT cells and transduced into rat BMSCs. After transduction, 81.3% rBMSCs successfully expressed green fluorescence. The hrGFP-rBMSCs were statically loaded on Bioglass-Collagen-Hyaluronic Acid-Phosphatidylserine (BG-COL-HYA-PS) scaffold in complete L-DMEM medium or osteogenic medium for 14 days. At 6h, a number of cells expressing green fluorescence can be observed by fluorescent microscopy. At day 7 and 14 after co-culture, the number of cells on the scaffold gradually increased. After 14 days for osteogenic induction, the hrGFP-rBMSCs and the interior of scaffold can be detected the expression of type I collagen. The results demonstrate that hrGFP labelling technique can detect visualizedly and effectively cell adhesion, proliferation and osteogenic differentiation in the construction of tissue-engineered bone in vitro.

Investigation on mechanical property of the compound scaffold of Sol-Gel bioactive glass/collegan / 医用生物力学

Objective To investigate the mechanical prosperity and degradation rate of the scaffolds with compounding collagen and the nano sol-gel derived bioactive glass were studied,and provide the theoretical basis for the further application of collagen based scaffolds.Method The scaffold with compounding collagen and the nano sol-gel derived bioactive glass(58S)were prepared using the freeze-drying techniques with the bioactive glass as phase addition.By affecting the aggregation state of the collagen fibers with adjusting the supplementation of bioactive glass to change the microstructures of the compound scaffolds and finatly the compound scaffolds with different mechanical properties were prepared.Results (1)As the aggregation state of the collagen fibers changes,the scaffolds with the coarser collagen fibers is prepared with the diameters 400-600 nm approximately.The coarser collagen fibers will play an important role in improving the mechanical property and slowing down the degradation rate of the collagen based scaffolds.(2)The interactions between bioactive glass and collagen are studied by FTIR and Raman technologies.When the quality of content of collagen in the compound scaffolds is lower than 20%,the secondary structure of collagen is damaged severely.Conclusion The composite scaffolds with the mass ratio of collagen to bioactive glass 40:60 has the best performance in mechanical property and degradation,which will be helpful for further applications.