BSA@IR780-loaded mesoporous polydopamine nanoparticles with enhanced photostability for multimodal imaging and photothermal therapy of tumors

Multifunctional phototherapy that integrates diagnostic and therapeutic modalities holds the potential to revolutionize cancer treatment. The near-infrared cyanine dye IR780 is known for its high spatial resolution imaging capabilities. When conjugated with bovine serum albumin (BSA), it effectively mitigates common challenges such as photobleaching and fluorescence quenching, making it widely used in tumor imaging. However, its limited photothermal conversion efficiency hinders its broader application in tumor therapy. To overcome these limitations, this study presents the design and development of an imaging-guided multifunctional nanoplatform: mesoporous polydopamine (MPDA)-BSA@IR780. Our findings demonstrate that MPDA, as a carrier, significantly improves the photostability of BSA@IR780. Furthermore, MPDA's superior photothermal properties enhance the photothermal efficacy of the platform, enabling MPDA-BSA@IR780 to function as a dual photothermal therapy (PTT) agent. In addition to its therapeutic potential, MPDA-BSA@IR780 serves as both a photoacoustic (PA) and fluorescence (FL) imaging probe, effectively guiding treatment decisions. Cellular assays reveal that MPDA-BSA@IR780 exhibits a robust photothermal effect, supporting promising therapeutic outcomes. In vivo studies further demonstrate that, following laser irradiation, MPDA-BSA@IR780 achieves near-complete tumor ablation without inducing significant toxicity, while also exhibiting excellent biocompatibility. In conclusion, this study introduces a safe and effective photothermal nanoparticle platform for tumor imaging, diagnosis, and treatment, providing a promising strategy for future biomedical applications.