Apolinário Alexsandra Conceição, Magoń Monika S, Pessoa Adalberto, Rangel-Yagui Carlota de Oliveira
Department of Biochemical and Pharmaceutical Technology, School of Pharmaceutical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 580-Bl.16, São Paulo 05508-000, Brazil.
Department of Chemistry, University College London, Christopher Ingold Building, 20 Gordon Street, London WC1H 0AJ, UK.
Nanomaterials (Basel). 2018 May 26;8(6):373. doi: 10.3390/nano8060373.
Polymersomes (PL), vesicles formed by self-assembly of amphiphilic block copolymers, have been described as promising nanosystems for drug delivery, especially of biomolecules. The film hydration method (FH) is widely used for PL preparation, however, it often requires long hydration times and commonly results in broad size distribution. In this work, we describe the challenges of the self-assembly of poly (ethylene glycol)-poly(lactic acid) (PEG-PLA) into PL by FH exploring different hydrophilic volume fraction () values of this copolymer, stirring times, temperatures and post-FH steps in an attempt to reduce broad size distribution of the nanostructures. We demonstrate that, alongside value, the methods employed for hydration and post-film steps influence the PEG-PLA self-assembly into PL. With initial FH, we found high PDI values (>0.4). However, post-hydration centrifugation significantly reduced PDI to 0.280. Moreover, extrusion at higher concentrations resulted in further improvement of the monodispersity of the samples and narrow size distribution. For PL prepared at concentration of 0.1% (/), extrusion resulted in the narrower size distributions corresponding to PDI values of 0.345, 0.144 and 0.081 for PEG-PLA, PEG-PLA and PEG-PLA, respectively. Additionally, we demonstrated that copolymers with smaller resulted in larger PL and, therefore, higher encapsulation efficiency (EE%) for proteins, since larger vesicles enclose larger aqueous volumes.
聚合物囊泡（PL）是由两亲性嵌段共聚物自组装形成的囊泡，已被描述为用于药物递送，尤其是生物分子递送的有前景的纳米系统。薄膜水化法（FH）被广泛用于PL的制备，然而，它通常需要较长的水化时间，并且通常会导致较宽的尺寸分布。在这项工作中，我们通过探索该共聚物的不同亲水体积分数（）值、搅拌时间、温度和薄膜水化后步骤，描述了聚（乙二醇）-聚（乳酸）（PEG-PLA）通过FH自组装成PL的挑战，试图减少纳米结构的宽尺寸分布。我们证明，除了值之外，用于水化和薄膜后步骤的方法也会影响PEG-PLA自组装成PL。初始FH时，我们发现多分散指数（PDI）值较高（>0.4）。然而，水化后离心显著降低了PDI至0.280。此外，在较高浓度下挤压导致样品的单分散性进一步改善和尺寸分布变窄。对于以0.1%（/）浓度制备的PL，挤压分别导致PEG-PLA、PEG-PLA和PEG-PLA的尺寸分布更窄，对应PDI值分别为0.345、0.144和0.081。此外，我们证明，较小的共聚物会导致更大的PL，因此蛋白质的包封效率（EE%）更高，因为更大的囊泡包围更大的水相体积。
