Zhang M, Li X H, Gong Y D, Zhao N M, Zhang X F
Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, China.
Biomaterials. 2002 Jul;23(13):2641-8. doi: 10.1016/s0142-9612(01)00403-3.
Chitosan (beta-1,4-D-glucosamine), a polysaccharide with excellent biological properties, has been widely used in biomedical fields, but many barriers still exist to its broader usage due to its chemical and physical limitations. Further work is needed to improve these properties, but changes of the chemical and physical properties will influence its biocompatibility, so the biological attribute of modified chitosan must be evaluated. In this study, the biocompatibility of chitosan modified by several methods was carefully evaluated at the cellular and protein levels using different physical and biological methods. The results provide a theoretical basis for screening biomaterials. We studied the properties of five kinds of materials made by blending chitosan with different types of polyethylene glycol (PEG). The properties included physical and chemical properties, such as mechanical strength, static contact angle, spectroscopy, thermodynamic attributes and so on. The mechanical properties were slightly improved with the proper amount of PEG, but the improvement was not obvious and was destroyed by the wrong proportion of PEG. Cultures of the cells and amounts and structures of the adsorbed proteins on different materials showed that the PEG effectively improved the biocompatibility of the materials. The PEG enhanced the protein adsorption, cell adhesion, growth and proliferation, but the effects were impaired by excessive PEG. The experiments also demonstrated that the optimum PEG concentration helped to maintain the natural structure of the protein adsorbed on the materials and that maintaining the natural structure benefited cell growth. Analysis of the results based on the intramolecular and intermolecular interaction forces leads to a basic theory for the modification of biomaterials.
壳聚糖（β-1,4-D-葡糖胺）是一种具有优异生物学特性的多糖，已在生物医学领域广泛应用，但由于其化学和物理局限性，在更广泛应用方面仍存在许多障碍。需要进一步开展工作来改善这些特性，但化学和物理性质的改变会影响其生物相容性，因此必须评估改性壳聚糖的生物学属性。在本研究中，使用不同的物理和生物学方法，在细胞和蛋白质水平仔细评估了几种方法改性的壳聚糖的生物相容性。研究结果为筛选生物材料提供了理论依据。我们研究了壳聚糖与不同类型聚乙二醇（PEG）共混制成的五种材料的性能。这些性能包括物理和化学性质，如机械强度、静态接触角、光谱学、热力学属性等。适量的PEG可使机械性能略有改善，但改善并不明显，且PEG比例不当会破坏机械性能。不同材料上细胞培养以及吸附蛋白质的数量和结构表明，PEG有效改善了材料的生物相容性。PEG增强了蛋白质吸附、细胞黏附、生长和增殖，但过量的PEG会削弱这些作用。实验还表明，最佳PEG浓度有助于维持吸附在材料上蛋白质的天然结构，而维持天然结构有利于细胞生长。基于分子内和分子间相互作用力对结果进行分析，得出了生物材料改性的基础理论。
