Photo/pH dual-responsive biocompatible poly(methacrylic acid)-based particles for triggered drug delivery

A novel dual-responsive (light and pH) particle based on poly(methacrylic acid), poly(methacrylic acid)–poly[1-(2-nitrophenyl)ethane-1,2-diyl bis(2-methylacrylate)]was prepared with the facile method of two-step homogeneous radical polymerization with methacrylic acid as the monomer and 1-(2-nitrophenyl)ethane-1,2-diyl bis(2-methylacrylate) as a photodegradable crosslinker. Photolytic assessments were conducted upon irradiation with a UV lamp; this led to particle disintegration caused by cleavage of the photolabile crosslinking points. The light-dependent degradation was investigated through particle size changes, absorption spectra variations, surface morphology changes, Fourier transform infrared spectroscopy, and the release of Nile red from the particles after irradiation. The pH dependence of the particle systems induced by the protonation and deprotonation of poly(methacrylic acid) was also confirmed by fluorescence spectroscopy. The triggered release of fluorescein diacetate was investigated to demonstrate that the release behavior in cells was light dependent. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 44003.