Nanodiamonds As a Platform for Targeted Delivery of Chlorin-Based Photosensitizers to Cancer Cells

Targeted delivery of photosensitizers is one of the main problems of the photodynamic therapy of cancer. Nanodiamonds hold much promise as a delivery platform because of their good sorption properties, functionally modifiable surfaces, and low biological toxicity of carbon. In this work, we present a rational design of nanodiamonds for targeted delivery of boronated derivative of e6 chloride to human A431 epidermoid carcinoma cells. Formation of hybrid complexes in aqueous solution is accompanied by deactivation of the excited states of the dye. This prevents generation of reactive oxygen species until the complex reaches the target. In the presence of lipid membranes, the photosensitizers leave the complex and exhibit their photodynamic activity. Modification of the nanodiamond surface by transferrin leads to an additional increase in the efficiency of photodynamic inactivation of cancer cells.