Functional poly(l-lysine) derivative nanogels with acidic pH-pulsed antitumor drug release properties

Abstract

We developed novel poly(l-lysine) [poly(Lys)] derivative nanogels with smart drug release properties. Poly(Lys) derivative was prepared after the chemical reaction of poly(Lys) and 3-diethylaminopropyl isothiocyanate (DEAP), and was coupled with poly(ethylene glycol) (PEG). The obtained poly(Lys-DEAP)-b-PEG was crosslinked by genipin (crosslinking agent) in an oil/water emulsion condition, producing poly(Lys) derivative nanogels. These nanogels (~95 nm in diameter, pH 7.4) showed volume expansion (~200 nm in diameter) in the endosomal pH (~pH 6.0) due to extensive proton absorption of DEAP moieties in the crosslinked nanogel core. These nanogels reversibly swelled at pH 6.0 and shrank at pH 7.4, correspond to maximized drug release at pH 6.0 and minimized drug release at pH 7.4. We conclude that this nanogel system will have great potential for tumor therapy.