Chlorin e6 conjugated copper sulfide nanoparticles for photodynamic combined photothermal therapy

The photo-based therapeutic approaches have attracted tremendous attention in recent years especially in treatment and management of tumors. Photodynamic and photothermal are two major therapeutic modalities which are being applied in clinical therapy. The development of nanomaterials for photodynamic combined with photothermal therapy has gained significant attention for its treatment efficacy. In the present study, we designed chlorin e6 (Ce6) conjugated copper sulfide (CuS) nanoparticles (CuS-Ce6 NPs) through amine functionalization and the synthesized nanoparticles act as a dual-model agent for photodynamic therapy and photothermal therapy. CuS-Ce6 NPs showed enhanced photodynamic effect through generation of singlet oxygen upon 670 nm laser illumination. The same nanoparticles exerted thermal response under an 808 nm laser at 2 W/cm². The fabricated nanoparticles did not show any cytotoxic effect toward breast cancer cells in the absence of light. In vitro cell viability assay showed a potent cytotoxicity in photothermal and photodynamic treatment. Rather than singular treatment, the photodynamic combined photothermal treatment showed an enhanced cytotoxic effect on treated cells. In addition, the CuS-Ce6 NPs exert a photoacoustic signal for non-invasive imaging of treated cells in tissue-mimicking phantom. In conclusion the CuS-Ce6 NPs act as multimodal agent for photo based imaging and therapy.