Application of sono-photochemical methods to cysteine-functionalized graphene quantum dots loaded with indium phthalocyanine for enhanced singlet oxygen generation

Abstract

Existing photodynamic therapy (PDT) agents face challenges such as low singlet oxygen production, severe photobleaching, and poor biocompatibility. To overcome these issues, we propose a novel method combining newly synthesized phthalocyanine with cysteine-functionalized graphene quantum dots (cys-GQDs). This approach aims to enhance singlet oxygen production, solubility and stability in biological environments. In this study a new indium phthalocyanine and its cys-GQDs (InPc@cys-GQDs) derivative were synthesized as a new sono-photosensitizer candidate for therapeutic applications. Their photochemical and sono-photochemical properties were evaluated, focusing on singlet oxygen generation efficiency. Additionally, the stability, photo- stability, cellular uptake, and biocompatibility of these agents were tested through in vitro assays. The results show that the InPc@cys-GQDs conjugate has significantly higher singlet oxygen yield, especially with sonophotodynamic method compared to only phthalocyanine agent. They also demonstrate improved cellular internalization and reduced cytotoxicity, suggesting they offer a promising advancement for clinical PDT applications.