Biocompatible cdots dual role: Nanophotosensitizers for hypoxic photodynamic therapy and scavenging nanozyme biosensing

Within this study we report a non-toxic nanomaterial suitable for Photodynamic Therapy (PDT) under hypoxic conditions. PDT relies on the production of reactive oxygen and nitrogen species that can lead to cancer cells death. Currently, PDT is limited by: the development of efficient photosensitizers that can produce these radicals in situ; and the oxygen level requirement. The produced Carbon Dots (Cdots) successfully destroy human melanoma cancer cells upon 5 min irradiation using 450 nm wavelength due to the in situ production of NO•. As such, this nanophotosensitizer is applicable regardless of the cells molecular oxygen levels. Additionally, this nanomaterial acts as a scavenging nanozyme biosensor allowing to follow-up, in situ, the released NO• concentration, thereby offering a tight control over the NO• concentration in real-time and, its maintenance within the therapeutic window. Hence, this work offers a novel theranostic and NO• scavenging nanozyme biosensing nanoplatform that allows high control for hypoxic-PDT cancer application even in low doses and with 5 min irradiation.