Spontaneous Formation of Giant Unilamellar Vesicles from Microdroplets of a Polyion Complex by Thermally Induced Phase Separation

Synthesis of Low-Dimensional Polyion Complex Nanomaterials via Polymerization-Induced Electrostatic Self-Assembly

Nanostructured polyion complexes (PICs) are appealing in biomaterials applications. Yet, conventional assembly suffers from the weakness in scale-up and reproducibility. Only a few low-dimensional PICs are available to date. Herein we report an efficient and scalable strategy to prepare libraries of low-dimensional PICs. It involves a visible-light-mediated RAFT polymerization of ionic monomer in the presence of a polyion of the opposite charge at 5-50 % w/w total solids concentration in water at 25 °C, namely, polymerization-induced electrostatic self-assembly (PIESA). A Vesicle, multi-compartmental vesicle, and large-area unilamellar nanofilm can be achieved in water. A long nanowire and porous nanofilm can be prepared in methanol/water. An unusual unimolecular polyion complex (uPIC)-sphere-branch/network-film transition is reported. This green chemistry offers a general platform to prepare various low-dimensional PICs with high reproducibility on a commercially viable scale under eco-friendly conditions.

Temperature-modulated noncovalent interaction controllable complex for the long-term delivery of etanercept to treat rheumatoid arthritis

The clinical applications of etanercept (Enbrel), an emerging therapeutic protein for rheumatoid arthritis (RA), are limited by its instability and low bioavailability. In this study, a long-term and efficient therapeutic nanocomplex formulation for RA treatment was developed in the form of a temperature-modulated noncovalent interaction controllable (TMN) complex based on a temperature-sensitive amphiphilic polyelectrolyte (succinylated pullulan-g-oligo(L-lactide); SPL). The TMN complexes were prepared by simply mixing the negatively charged SPL copolymer and the positively charged etanercept via electrostatic interaction at 4 °C below the polymer's clouding temperature (CT), and the resulting complex demonstrated significantly improved salt and serum stability with increased hydrophobic interactions at temperatures (physiological condition, 37.5 °C) above the CT. An in vitro study of the bioactivity of etanercept indicated that the TMN complex improves the long-term stability of etanercept in an aqueous environment because of the exposure of the functional active site and the molecular chaperone-like effect of the hydrophobic copolymer. This formulation possessed prolonged in vivo pharmacokinetic parameters. In a collagen-induced arthritis RA rat model, we verified the outstanding therapeutic effect of the TMN complexes. These results imply that this approach would be widely applied to protein and peptide delivery systems.