Encapsulation of submicron-sized silica particles by stimuli-responsive copolymer shell layer

This study examined the encapsulation of submicron-sized silica particles by stimuli-responsive copolymer shell layer. Silica/poly(2-dimethylaminoethyl methacrylate-N-isopropylacrylamide-ethyleneglycol dimethacrylate), abbreviated as silica/P(DM-NIPAM-EGDM) core-shell composite polymer particles, were prepared by the seeded copolymerization of DM, NIPAM and EGDM in the presence of silica particles. The morphology and size distribution were analyzed by scanning electron microscopy. The surface composition showed silica particles covered with a copolymer shell layer consisting of P(DM-NIPAM-EGDM). The temperature and pH dependent adsorption behavior of the low molecular weight surfactants and biomolecules on the silica/P(DM-NIPAM-EGDM) composite polymer particles indicated a stimuli-responsive phase transition. The activity of the adsorbed trypsin (TR) on the composite particles remained high compared to the free TR and adsorbed TR on silica particles.