Temperature and salt responsive zwitterionic polysulfamide-based nanogels with surface regeneration ability and controlled drug release

Abstract

Although zwitterionic polymers with consistent anti-fouling ability have been extensively studied, the responsive versions with switchable anti-fouling ability have been much less explored. Herein, a novel zwitterionic polysulfamide-based monomer named (2-((2-(methacryloyloxy)ethyl)dimethylammonio)acetyl)(phenylsulfonyl)amide (MEDAPA) has been developed for the first time and a series of nanogels based on MEDAPA (named PMEDAPA) with different degrees of crosslinking were facilely fabricated by precipitation polymerization. The obtained PMEDAPA nanogels showed reversible heating-induced swelling and cooling-induced shrinking, demonstrating upper critical solution temperature (UCST) type of thermo-responsiveness. Furthermore, PMEDAPA nanogels remained in a shrinking state in water and became highly swollen in salt solutions, showing the salt-responsiveness induced by the anti-polyelectrolyte effect. Owing to the temperature- or salt-induced hydrophilic–hydrophobic transition, PMEDAPA nanogels showed bio-adhesion behavior at low temperatures or in water and anti-fouling behavior at high temperatures or in salt solutions. Notably, PMEDAPA nanogels absorb proteins significantly in water and desorb proteins sufficiently in 0.9 wt% NaCl solutions, which could be reversible for more than 8 times without sacrificing the separation efficiency. In addition, doxorubicin could be effectively loaded into PMEDAPA nanogels, which showed controlled drug release at different temperatures. Therefore, PMEDAPA nanogels may be an intriguing system for the fabrication of an intelligent interface with facile regenerative properties and smart drug delivery carriers in the future.