Neutral and positively charged indium(III) phthalocyanines: Comparative evaluation of the effect of light and ultrasound-assisted light stimulation on singlet oxygen production and DNA interaction analysis

Abstract

Nowadays, the development of sonophoto-activated phthalocyanine-based therapeutic agents and studies to determine their photochemical and sono-photochemical properties are very important in improving the success of the treatment of cancer with sonophotodynamic therapy (SPDT). Indium(III) phthalocyanines are among the most effective ones with their high singlet oxygen generation potential. Herein, a neutral indium(III) phthalocyanine (2) and its water-soluble cationic indium(III) phthalocyanine derivative (2a) were synthesized. The synthesized phthalocyanines were sonochemically, photochemically and sono-photochemically excited and the excitation method effect on singlet oxygen generation was systematically studied by a comprehensive analysis. The experimental measurements indicated that exceptionally high quantum yields were obtained following sonophotochemical investigations. In addition to photochemical and sono-photochemical studies, the interaction of 2a with deoxyribonucleic acid (DNA) was investigated. The DNA binding constant (Kb) for 2a is 1.66 x 106 M- 1 and the quenching constant (Kq) is 8.18 x 1013 M- 1s- 1. The results indicate that these sensitizers may serve as potential candidate sensitizer molecules for application in advanced cancer therapies.