Stimuli-responsive poly (4-vinyl pyridine) hydrogel nanoparticles: Synthesis by nanoprecipitation and swelling behavior.

Stimuli-responsive polymer nanospheres of poly(4-vinyl pyridine) have been obtained using a very simple modified nanoprecipitation technique. This process is conducted without help of crosslinking or monomer polymerization, methods used until now for this purpose. The influence of the surfactant concentration used in the preparation on particle size, the stability and the swelling kinetics of these hydrogels are studied. Furthermore, the nanospheres are shown to be pH and ionic strength responsive, undergoing swelling with equilibration times in the range of days. Dynamic light scattering and scanning electron microscopy were used to determine the structure, size, dispersion and morphology of these materials. Due to their response to stimuli, these nanoparticles are of potential interest for a number of biomedical applications such as drug delivery or biosensors. (C) 2010 Elsevier Inc. All rights reserved.