Preparation and Properties of Polyacrylic Acid/Soluble Starch Complex Nanoparticles by Surfactant-Free Polymerization

Polymer nanoparticles have made progress in pharmaceutical nanotechnologies due to their efficient drug delivery. However, considerable amounts of surfactant are required during polymerization, which inevitably brings some potential problems. Herein, template polymerization is utilized to synthesize polyacrylic acid/soluble starch (PAA/SS) complex nanoparticles by surfactant-free polymerization. As a template, soluble starch (S-starch, SS) nanoparticles are obtained by nanoprecipitation due to their polyhydroxy structure. The resultant complex nanoparticles with pH sensitivity have core–shell structures, which facilitates their use as nanoparticles in preparation of gelatin-like materials. Another interesting property of PAA/SS complex nanoparticles is that the SS template can be removed by α-amylase, then PAA nanocapsules are obtained. A hypothesis for the mechanisms of PAA/SS complex nanoparticles formation and PAA nanocapsules preparation with α-amylase is also proposed.