Department of Biomedical Engineering, Tufts University, Medford, Massachusetts 02155, United States.
Biomacromolecules. 2010 Dec 13;11(12):3406-12. doi: 10.1021/bm100925s. Epub 2010 Oct 28.
Silk-fibroin-based biomaterials have been widely utilized for a range of biomaterial-related systems. For all these previously reported systems, the β-sheet forming feature of the silk was the key stabilizing element of the final material structure. Herein, we describe a different strategy, based on the engineering of silk-based ionomers that can yield stable colloidal composites or particle suspensions through electrostatic interactions. These silk-based ionomers were obtained by carbodiimide-mediated coupling of silk fibroin with polylysine hydrobromide and polyglutamic acid sodium salts, respectively. Colloidal composites could be obtained by mixing the ionomeric pair at high concentration (i.e., 25% w/v), while combining them at lower concentrations (i.e., 5% w/v) yielded particle suspensions. The assembly of the ionomers was driven by electrostatic interactions, pH-dependent, and reversible. The network assembly appeared to be polarized, with the interacting poly(amino acid) chains clustered to the core of the particles and the silk backbone oriented outward. In agreement with this assembly mode, doxorubicin, a hydrophilic antitumor drug, could be released at a slow rate, in a pH-dependent manner, indicating that the inside of the ionomeric particles was mainly hydrophilic in nature.
基于丝素蛋白的生物材料已被广泛应用于多种与生物材料相关的系统。对于所有这些之前报道的系统，丝的β-折叠形成特征是最终材料结构的关键稳定元素。在此，我们描述了一种不同的策略，基于丝素蛋白离聚物的工程设计，通过静电相互作用可以产生稳定的胶体复合材料或颗粒悬浮液。这些丝素蛋白离聚物是通过碳二亚胺介导的丝素蛋白与聚赖氨酸氢溴酸盐和聚谷氨酸钠盐的偶联分别获得的。通过在高浓度（即 25%w/v）下混合离聚物对可以获得胶体复合材料，而在较低浓度（即 5%w/v）下组合则可以得到颗粒悬浮液。离聚物的组装是由静电相互作用驱动的，受 pH 值影响且是可逆的。该网络组装似乎是极化的，相互作用的聚（氨基酸）链聚集到颗粒的核心，而丝素骨架向外定向。与这种组装模式一致，亲水性抗肿瘤药物阿霉素可以以 pH 依赖性的方式缓慢释放，表明离聚物颗粒的内部主要是亲水性的。
