Preparation of biocompatible nanocapsules with temperature-responsive and bioreducible properties

Stimuli-responsive biocompatible nanocarriers are very promising for controlled drug release. Here, we report redox- and temperature-responsive biocompatible nanocapsules prepared by growing a temperature-responsive biocompatible shell from 3-(trimethoxysilyl)propyl methacrylate-modified silica nanoparticles (SiO₂-MPS) via precipitation polymerization, cross-linking the shell with bioreducible chemical linkages, and subsequently removing the silica core by hydrofluoric acid etching. The produced nanocapsules are redox- and temperature-responsive. TEM, FT-IR, TGA, and XPS were used to characterize the nanocapsules. Dynamic light scattering (DLS) was performed to demonstrate the bioreducible and temperature-responsive properties of the nanocapsules. The lower critical solution temperature (LCST) of the nanocapsules can be tuned precisely. Fluorescein isothiocyanate (FITC) was encapsulated into the nanocapsules and used as a model drug molecule to demonstrate the controlled release behavior under external stimuli.