Tumor microenvironment-responsive charge reversal zinc phthalocyanines based on amino acids for photodynamic therapy

Amino acid substituted zinc phthalocyanines which are capable of reversing their charge from negative to positive in response to tumor microenvironment have been prepared by the isoelectric pHs regulation and charge reversal sensitivity enhancement. The charge reversal abilities of the prepared zinc phthalocyanines were judged by their isoelectric pHs and zeta potential values. The UV-Vis spectra, singlet oxygen generation ability, cellular uptake and in vitro anticancer ability of the prepared zinc phthalocyanines were investigated to study the influences of charge reversal on photodynamic activities. Charge reversible tetra- and octa-substituted glutamic acid ZnPcs showed enhanced singlet oxygen generation ability, cellular uptake and photocytotoxicity towards cancer cells, and were considered as promising photosensitizers for photodynamic therapy. (C) 2015 Elsevier Ltd. All rights reserved.