Biotechnology Division, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, People's Republic of China.
J Biomed Mater Res A. 2010 Mar 15;92(4):1357-65. doi: 10.1002/jbm.a.32437.
Alginate-chitosan-alginate (ACA) microcapsules have been developed as a device for the transplantation of living cells. However, protein adsorption onto the surface of microcapsules immediately upon their implantation decides their ultimate biocompatibility. In this work, the chemical composition of the ACA membranes was determined using X-ray photoelectron spectroscopy (XPS). The surface wettability and charge were determined by contact angle and zeta potential measurements, respectively. Then, the effects of surface wettability and charge on bovine fibrinogen (Fgn) and gamma globulin (IgG) adsorption onto ACA microcapsules were evaluated. The results showed that ACA microcapsules had a hydrophilic membrane. So, the surface wettability of ACA microcapsules had little effect on protein adsorption. There was a negative zeta potential of ACA microcapsules which varies with the viscosity or G content of alginate used, indicating a varying degree of net negatively charged groups on the surface of ACA microcapsules. The amount of adsorbed protein increased with increasing of positive charge. Furthermore, the interaction between proteins and ACA microcapsules is dominated by electrostatic repulsion at pH 7.4 and that is of electrostatic attraction at pH 6.0. This work could help to explain the bioincompatibility of ACA microcapsules and will play an important role in the optimization of the microcapsule design.
藻酸盐-壳聚糖-藻酸盐（ACA）微胶囊已被开发为用于移植活细胞的装置。然而，微胶囊在植入后表面立即吸附蛋白质决定了它们最终的生物相容性。在这项工作中，使用 X 射线光电子能谱（XPS）确定了 ACA 膜的化学组成。通过接触角和zeta 电位测量分别确定了表面润湿性和电荷。然后，评估了表面润湿性和电荷对牛纤维蛋白原（Fgn）和γ球蛋白（IgG）吸附到 ACA 微胶囊上的影响。结果表明，ACA 微胶囊具有亲水性膜。因此，ACA 微胶囊的表面润湿性对蛋白质吸附的影响很小。ACA 微胶囊具有负 zeta 电位，其随所用藻酸盐的粘度或 G 含量而变化，表明 ACA 微胶囊表面带有的净负电荷基团的程度不同。吸附的蛋白质量随正电荷的增加而增加。此外，在 pH 7.4 时，蛋白质与 ACA 微胶囊之间的相互作用主要是静电排斥，而在 pH 6.0 时则是静电吸引。这项工作有助于解释 ACA 微胶囊的生物不相容性，并将在微胶囊设计的优化中发挥重要作用。
