Department of Chemistry, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, PR China.
Colloids Surf B Biointerfaces. 2012 May 1;93:121-6. doi: 10.1016/j.colsurfb.2011.12.029. Epub 2012 Jan 4.
The polyelectrolytes multilayer microcapsules considered as a good matrix can meet the requirements of protein encapsulation and release. It is important to understand the factors affecting the encapsulation and release of proteins in capsules. In this study, the eight layers hollow capsules (PSS/PAH)(4) and nine layers hollow capsules (PSS/PAH)(4)PSS are fabricated. The protein, R-Phycoerythrins (R-PEs) is employed as a probe instead of fluorescein isothiocyanate labeled proteins to investigate protein loading capacities on capsules as a function of pH, since R-PEs demonstrate an excellent stability over a broad pH range. The loading capacities of R-PEs on capsules (PSS/PAH)(4) or (PSS/PAH)(4)PSS are demonstrated to be sensitive to pH. The R-PE encapsulated in capsules exhibit the largest load capacity around isoelectric point of the protein independent of outer most layer of polyelectrolytes. However, if the pH of buffer is far away from the isoelectric point of the protein, they are absorbed on the surface of capsules. Based on a Freundlich model, capsules take up proteins on their surface by monolayer adsorption. The release process of R-PEs from microcapsules to solution is also shown to be sensitive to pH. Proteins show a faster release process around isoelectric point. Therefore, the pH sensitive polyelectrolyte microcapsules may offer a promising delivery system for loading and releasing proteins in biological systems depending on environment.
作为一种良好基质的聚电解质多层微胶囊可以满足蛋白质包封和释放的要求。了解影响蛋白质在胶囊中包封和释放的因素非常重要。在这项研究中,制备了八层层空胶囊(PSS/PAH)(4)和九层层层空胶囊(PSS/PAH)(4)PSS。将蛋白质藻红蛋白(R-Phycoerythrins,R-PEs)用作探针,而不是用荧光素异硫氰酸酯标记的蛋白质来研究蛋白质在胶囊中的负载能力随 pH 的变化,因为 R-PEs 在较宽的 pH 范围内表现出极好的稳定性。R-PEs 在胶囊(PSS/PAH)(4)或(PSS/PAH)(4)PSS 上的负载能力被证明对 pH 敏感。R-PE 包封在胶囊中,其负载能力在蛋白质的等电点附近最大,而与最外层聚电解质无关。然而,如果缓冲液的 pH 远离蛋白质的等电点,它们就会被吸附在胶囊的表面。基于 Freundlich 模型,胶囊通过单层吸附在表面上吸收蛋白质。R-PEs 从微胶囊到溶液中的释放过程也对 pH 敏感。蛋白质在等电点附近表现出更快的释放过程。因此,基于 pH 敏感的聚电解质微胶囊可以为在生物系统中加载和释放蛋白质提供一种有前途的输送系统,这取决于环境。