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Abstract  Solutions of poly(N-isopropylacrylamide) (PNIPA) with ionic and nonionic surfactants were investigated by light scattering methods at temperatures 15–45 �C. In contrast to previous studies, where surfactants were used in excess, lower concentrations of surfactants were used. The formation of well-defined nanoparticles of PNIPA was observed on heating above the lower critical solution temperature. The effect of PNIPA and surfactant concentrations, and molecular weight of PNIPA on nanoparticle parameters and on the phase transition temperature of PNIPA solutions were investigated. An interpretation based on stabilization of PNIPA nuclei by surfactants was suggested. [ABSTRACT FROM AUTHOR]

Abstract??Poly(adipoyl chloride-alt-cystamine) nanoparticles covalently coated with poly(ethylene oxide) (Mw?=?2,000 or 5,000) were prepared as a model of glutathione-degradable drug, protein, or deoxyribonucleic acid delivery systems. The polyamide forming the micellar core has disulfide bonds in the main chain and thus its degradation gives low molecular weight products. The degradation of nanoparticles by the action of glutathione in the reduced or oxidized forms was monitored by time dependencies of the light scattering intensity at 37??C in media modeling intracellular environment. The lifetimes of nanoparticles were determined. The reductive degradation of the nanoparticles by the reaction with reduced glutathione is an order of magnitude faster than their spontaneous degradation. The effect of nanoparticle concentration and solution pH was also investigated. [ABSTRACT FROM AUTHOR]