Key Laboratory of Drug Targeting and Drug Delivery System (Ministry of Education), West China School of Pharmacy , Sichuan University , No. 17, Block 3, South Renmin Road , Chengdu 610041 , P. R. China.
ACS Appl Mater Interfaces. 2018 Mar 28;10(12):9916-9928. doi: 10.1021/acsami.7b16524. Epub 2018 Mar 15.
Nanoparticles (NPs) for oral delivery of peptide/protein drugs are largely limited due to the coexistence of intestinal mucus and epithelial barriers. Sequentially overcoming these two barriers is intractable for a single nanovehicle due to the requirements of different or even contradictory surface properties of NPs. To solve this dilemma, a mucus-penetrating virus-inspired biomimetic NP with charge reversal ability (P-R8-Pho NPs) was developed by densely coating poly(lactic- co-glycolic acid) NPs with cationic octa-arginine (R8) peptide and specific anionic phosphoserine (Pho). The small size (81.81 nm) and viruslike neutral charged surface (-2.39 mV) of the biomimetic NPs achieved rapid mucus penetration, which was almost equal to that of the conventional PEGylated mucus-penetrating nanoparticles. The hydrolysis of surface-anchored anionic Pho was achieved by intestinal alkaline phosphatase, which led to the turnover of ζ potential to positive (+7.37 mV). This timely charge reversal behavior also exposed cationic R8 peptide and induced efficient cell-penetrating peptide (CPP)-mediated cellular uptake and transepithelial transport on Caco-2/E12 cocultured cell model. What's more, P-R8-Pho NPs showed excellent stability in simulated gastrointestinal conditions and enhanced absorption in intestine in vivo. Finally, oral administration of insulin-loaded P-R8-Pho NPs enabled to induce a preferable hypoglycemic effect and a 1.9-fold higher oral bioavailability was achieved compared with single CPP-modified P-R8 NPs on diabetic rats. The combinative application of biomimetic mucus-penetrating strategy and enzyme-responsive charge reversal strategy in a single nanovehicle could sequentially overcome mucus and epithelial barriers, thus showing great potential for the oral peptide/protein delivery.
纳米颗粒（NPs）在用于口服递送肽/蛋白质药物时受到很大限制，这主要是由于肠道黏液和上皮屏障的共同存在。由于单个纳米载体需要不同甚至相反的表面性质，因此连续克服这两种屏障对于单一纳米载体来说是难以实现的。为了解决这一困境，通过将阳离子八精氨酸（R8）肽和特定的阴离子磷酸丝氨酸（Pho）密集涂覆于聚（乳酸-共-乙醇酸）NPs 上，开发了一种具有电荷反转能力的模仿病毒的仿生纳米颗粒（P-R8-Pho NPs）。仿生 NPs 的小尺寸（81.81nm）和类病毒中性带电表面（-2.39mV）实现了快速的黏液穿透，几乎与常规的聚乙二醇化的穿透黏液纳米颗粒相当。表面锚定的阴离子 Pho 被肠道碱性磷酸酶水解，导致 ζ 电位转变为正（+7.37mV）。这种及时的电荷反转行为还暴露了阳离子 R8 肽，并诱导了在 Caco-2/E12 共培养细胞模型上的高效细胞穿透肽（CPP）介导的细胞摄取和跨上皮转运。更重要的是，P-R8-Pho NPs 在模拟胃肠道条件下表现出优异的稳定性，并在体内增强了肠道吸收。最后，胰岛素负载的 P-R8-Pho NPs 的口服给药能够诱导更好的降血糖效果，与单一 CPP 修饰的 P-R8 NPs 相比，在糖尿病大鼠中实现了 1.9 倍的口服生物利用度。在单个纳米载体中联合应用仿生穿透黏液策略和酶响应电荷反转策略可以顺序克服黏液和上皮屏障，因此在口服肽/蛋白质递送上具有很大的潜力。
