Polyion complex vesicles (PICsomes) formed from a self-assembly of an oppositely charged pair of block- and homo-polyelectrolytes have shown exceptional features for functional loading of bioactive agents. Nevertheless, the stability of PICsomes is often jeopardized in a physiological environment, and only PICsomes having chemically cross-linked membranes have endured in harsh in vivo conditions, such as in the bloodstream. Herein, we developed versatile PICsomes aimed to last in in vivo settings by stabilizing their membrane through a combination of ionic and hydrogen bonding, which is widely found in natural proteins as a salt bridge, by controlled introduction of guanidinium groups in the polycation fraction toward concurrent polyion complexation and hydrogen bonding. The guanidinylated PICsomes were successfully assembled under physiological salt conditions, with precise control of their morphology by tuning the guanidinium content, and the ratio of anionic and cationic components. Guanidinylated PICsomes with 100 nm diameter, which are relevant to nanocarrier development, were stable in high urea concentration, at physiological temperature, and under serum incubation, persisting in blood circulation in vivo.

中文翻译：

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胍盐基团衍生的多个氢键形成增强的生理条件下的稳健多离子复合物囊泡（PICsomes）

由一对带相反电荷的嵌段和均聚电解质的自组装形成的聚离子复合囊泡（PICsomes）具有生物活性剂功能性装载的特殊功能。然而，PICsomes的稳定性经常在生理环境中受到损害，并且只有具有化学交联膜的PICsomes在恶劣的体内条件下（例如在血液中）才可以忍受。本文中，我们开发了旨在在体内持续使用的多功能PICsomes通过离子和氢键的结合来稳定其膜，这是在天然蛋白质中广泛存在的盐桥形式，它是通过控制地将聚阳离子部分中的胍基引入同时的多离子络合和氢键来稳定的。胍基化的PICsomes在生理盐条件下成功组装，可通过调节胍盐的含量以及阴离子和阳离子组分的比例来精确控制其形态。与纳米载体的发展有关的直径100 nm的胍基化PICsomes在高尿素浓度，生理温度和血清孵育下稳定，在体内血液循环中持续存在。