Synthesis of Poly(acrylic acid) Nanogels and Application in Loading and Release of an Oligothiophene Fluorophore and Its Bovine Serum Albumin Conjugate.

Nanometer-sized poly(acrylic acid) (PAA) hydrogels were synthesized by emulsion polymerization of methyl acrylate and subsequent acid hydrolysis, and their pH-dependent swelling behaviour was studied by dynamic light scattering. To determine the suitability of PAA nanogels as pH-sensitive carriers for biomedical applications, loading and release of an oligothiophene fluorophore and its albumin conjugate onto the PAA nanogels were investigated as a function of pH by absorption and photoluminescence measurements. It was observed that loading and release processes of both the oligothiophene and its conjugate could be controlled by changing pH of their solutions.