Modelling the quenching effect of chloroaluminum phthalocyanine and graphene oxide interactions: implications for phototherapeutic applications

Photodynamic therapy (PDT) and photothermal therapy (PTT) are promising candidates for cancer treatment and their efficiency can be further enhanced by using a combination of both. While chloroaluminum phthalocyanine (AlClPc) has been studied extensively as a photosensitizer in PDT, nanographene oxide (nGO) has shown promise in PTT due to its high absorption of near-infrared radiation. In this work, we investigate the energy transport between AlClPc and nGO for their combined use in phototherapies. We use density functional theory (DFT) and time-dependent DFT to analyze the electronic structure of AlClPc and its interaction with nGO. Based on experimental parameters, we model the system's morphology and implement it in Kinetic Monte Carlo (KMC) simulations to investigate the energy transfer mechanism between the compounds. Our KMC calculations show that the experimentally observed fluorescence quenching requires modeling both the energy transfer from dyes to nGO and a molecular aggregation model. Our results provide insights into the underlying mechanisms responsible for the fluorescence quenching observed in AlClPc/nGO aggregates, which could impact the efficacy of photodynamic therapy.