A Dual-Responsive Morphologically-Adaptable Nanoplatform for Targeted Delivery of Activatable Photosensitizers in Precision Photodynamic Therapy.

Photodynamic therapy (PDT) is an effective approach for treating melanoma. However, the photosensitizers employed in PDT can accumulate in healthy tissues, potentially causing harm to normal cells and resulting in side effects such as heightened photosensitivity. To address this, an activatable photosensitizer (PSD) by linking PpIX with a fluorescence quencher using a disulfide bond is designed. PSD responded to endogenous GSH, showing high selectivity for A375 cells. To enhance PSD's bioavailability and anticancer efficacy, an enzyme-responsive nanoplatform based on a lonidamine-derived self-assembling peptide is developed. Initially, PSD and the peptide self-assembled into nanoparticles, displaying potent tumor targeting of PSD in vivo. Upon cell uptake, these nanoparticles specifically responded to elevated cathepsin B, causing nanoparticle disintegration and releasing PSD and lonidamine prodrug (LND-1). PSD is selectively activated by GSH for cancer-specific fluorescence imaging and precision PDT, while LND-1 targeted mitochondria, forming a fibrous lonidamine depot in situ and intensifying photosensitizer's cytotoxicity through ROS generation, mitochondrial dysfunction, and DNA damage. Notably, intravenous administration of LND-1-PEG@PSD with light irradiation significantly suppressed A375-xenografted mouse tumor growth, with minimal systemic toxicity. Together, the synergy of activatable photosensitizer and enzyme-responsive nanoplatform elevates PDT precision and diminishes side effects, showcasing significant potential in the realm of cancer nanomedicine.