Department of Biological Science and Bioengineering, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, Shaanxi, People's Republic of China.
Appl Microbiol Biotechnol. 2018 Apr;102(7):3229-3241. doi: 10.1007/s00253-018-8790-2. Epub 2018 Mar 1.
Polyhydroxyalkanoate (PHA) is a class of microbial synthesized biodegradable and biocompatible aliphatic polymer which has been developed into nanoparticles (NPs) for sustained release of hydrophobic compounds. Taking advantage of the natural PHA binding protein PhaP which could be steadily adsorbed onto PHA NPs through hydrophobic interaction, a tumor targeting system was developed in this study by presenting an epidermal growth factor receptor (EGFR)-targeting peptide (ETP) on the surface of PHA NPs, via PhaP mediated adsorption. To reveal the effects of residual emulsifiers on PhaP mediated ETP modification and optimize the tumor targeting capacity of the system, a novel emulsifier-free PHA NPs (EF-NPs) was fabricated together with other two kinds of conventional emulsifier-required PHA NPs (PVA-NPs and P68-NPs, which were prepared with poly(vinyl alcohol) (PVA) and Pluronic F68 as emulsifiers, respectively). By analyzing the surface hydrophobicity, the amount of adsorbed fusion protein, and the cellular uptake of all kinds of PHA NPs, our results demonstrated that EF-NPs with stronger surface hydrophobicity were the most proper formulation for further PhaP mediated ETP functionalization. The residual PVA and Pluronic F68 affected the modification efficiency and secondary structure of ETP-PhaP fusion protein, and finally obstructed the targeting effect of ETP-PhaP modified PVA-NPs and P68-NPs to EGFR over-expressed tumor cells. The animal experiment further confirmed the effectiveness and feasibility of in vivo application of ETP-PhaP functionalized EF-NPs, indicating that it could be served as a promising tumor targeting system with satisfactory EGFR targeting ability. This PhaP mediated bio-modification process also opens a wide way for developing various PHA-based targeting systems by presenting different tumor or other tissue-specific targeting peptides.
聚羟基脂肪酸酯（PHA）是一类微生物合成的可生物降解和生物相容的脂肪族聚合物，已被开发成纳米颗粒（NPs），用于疏水性化合物的持续释放。利用能够通过疏水相互作用稳定吸附到 PHA NPs 上的天然 PHA 结合蛋白 PhaP，本研究通过在 PHA NPs 表面呈现表皮生长因子受体（EGFR）靶向肽（ETP），开发了一种肿瘤靶向系统，该系统通过 PhaP 介导的吸附来实现。为了揭示残留乳化剂对 PhaP 介导的 ETP 修饰的影响，并优化该系统的肿瘤靶向能力，本研究一起制备了一种新型无乳化剂 PHA NPs（EF-NPs），以及另外两种需要常规乳化剂的 PHA NPs（PVA-NPs 和 P68-NPs，分别使用聚（乙烯醇）（PVA）和 Pluronic F68 作为乳化剂制备）。通过分析各种 PHA NPs 的表面疏水性、吸附融合蛋白的量和细胞摄取，我们的结果表明，具有更强表面疏水性的 EF-NPs 是进一步进行 PhaP 介导的 ETP 功能化的最合适配方。残留的 PVA 和 Pluronic F68 影响了 ETP-PhaP 融合蛋白的修饰效率和二级结构，最终阻碍了 ETP-PhaP 修饰的 PVA-NPs 和 P68-NPs 对 EGFR 过表达肿瘤细胞的靶向作用。动物实验进一步证实了 ETP-PhaP 功能化 EF-NPs 在体内应用的有效性和可行性，表明它可以作为一种有前途的肿瘤靶向系统，具有令人满意的 EGFR 靶向能力。这种 PhaP 介导的生物修饰过程也为通过呈现不同的肿瘤或其他组织特异性靶向肽来开发各种基于 PHA 的靶向系统开辟了广阔的道路。
