Constructing Asymmetric Polyion Complex Vesicles via Template Assembling Strategy: Formulation Control and Tunable Permeability.

A strategy for constructing polyion complex vesicles (PICsomes) with asymmetric structure is described. Poly(methylacrylic acid)--poly(-isopropylacrylamide) modified gold nanoparticles (PMAA--PNIPAm-@-Au NPs) were prepared and then assembled with poly(ethylene glycol)--poly[1-methyl-3-(2-methacryloyloxy propylimidazolium bromine)] (PEG--PMMPImB) via polyion complex of PMMA and PMMPImB. After removing the Au NPs template, asymmetric PICsomes composed of a PNIPAm inner-shell, PIC wall, and PEG outer-corona were obtained. These PICsomes have low protein absorption and thermally tunable permeability, provided by the PEG outer-corona and the PNIPAm inner-shell, respectively. Moreover, PICsome size can be tailored by using templates of predetermined sizes. This novel strategy for constructing asymmetric PICsomes with well-defined properties and controllable size is valuable for applications such as drug delivery, catalysis and monitoring of chemical reactions, and biomimetics.