CAS Key Laboratory of Soft Matter Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, Department of Polymer Science and Engineering, University of Science and Technology of China, 230026, Hefei, Anhui, China.
Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Biomaterials Research Center, School of Biomedical Engineering, Southern Medical University, 510515, Guangzhou, China.
Nat Commun. 2020 Mar 23;11(1):1524. doi: 10.1038/s41467-020-15304-x.
Compared to liposomes, polymersomes of block copolymers (BCPs) possess enhanced stability, along with compromised bilayer permeability. Though polyion complex vesicles (PICsomes) from oppositely charged block polyelectrolytes possess semipermeable bilayers, they are unstable towards physiologically relevant ionic strength and temperature; moreover, permselectivity tuning of PICsomes has remained a challenge. Starting from a single component diblock or triblock precursor, we solve this dilemma by stimuli-triggered chemical reactions within pre-organized BCP vesicles, actuating in situ polymersome-to-PICsome transition and achieving molecular size-selective cargo release at tunable rates. UV light and reductive milieu were utilized to trigger carboxyl decaging and generate ion pairs within hydrophobic polymersome bilayers containing tertiary amines. Contrary to conventional PICsomes, in situ generated ones are highly stable towards extreme pH range (pH 2-12), ionic strength (~3 M NaCl), and elevated temperature (70 °C) due to multivalent ion-pair interactions at high local concentration and cooperative hydrogen bonding interactions of pre-organized carbamate linkages.
与脂质体相比，嵌段共聚物的聚合物囊（BCPs）具有增强的稳定性，同时双层渗透性降低。虽然来自带相反电荷的嵌段聚电解质的聚离子复合囊（PICsomes）具有半透性双层，但它们对生理相关的离子强度和温度不稳定；此外，PICsomes 的选择透过性调节仍然是一个挑战。从单一成分的二嵌段或三嵌段前体出发，我们通过在预先组织的 BCP 囊泡内的刺激触发化学反应来解决这一困境，在原位触发聚合物囊泡到 PICsomes 的转变，并以可调的速率实现分子尺寸选择性货物释放。利用紫外光和还原环境触发含有叔胺的疏水性聚合物双层中的羧酸脱保护反应，并在其中生成离子对。与传统的 PICsomes 不同，由于在高局部浓度下的多价离子对相互作用和预先组织的氨基甲酸酯键的协同氢键相互作用，原位生成的 PICsomes 对极端 pH 值范围（pH 2-12）、离子强度（~3 M NaCl）和升高的温度（70°C）非常稳定。
