A facile way to fabricate pH-sensitive charge-conversion polymeric nanoparticles with tunable pH conversion point

Abstract

pH-Sensitive charge-conversion polymeric nanoparticles could significantly enhance drug bioavailability due to improved tumor cell internalization. However, the extracellular pH of tumors is significantly different for tumors of different histology and volume. To address this point, a series of pH-sensitive charge-conversion succinyl chitosan–O–poly(ε-caprolactone) (SC–O–PCL) nanoparticles with a tunable pH conversion point were fabricated through a facile method. Surface zeta potential of SC–O–PCL nanoparticles can change from negative (physiological pH) to positive in acidic conditions. The positive charges on the nanoparticles were beneficial to tumor cell internalization, leading to enhanced drug bioavailability. Also, the pH conversion point can be modulated in a wide range to match the varied tumor extracellular pH. Furthermore, the nanoparticles can encapsulate the antitumor drug doxorubicin (Dox) effectively and release Dox quickly in response to an acidic environment. This kind of smart nanoparticles may be a feasible candidate for individual tumor therapy.