DSPE-PEG-Coated Uniform Nitrogen-Doped Carbon Capsules for NIR-Mediated Synergistic Chemophototherapy of Skin Cancer

Uniform monodispersed nitrogen-doped carbon spheres have been emerging as an exciting platform for multipurpose medical applications like photothermal therapy and photoacoustic imaging and as carriers for aromatic anticancer drugs. However, synthesis of uniform N-doped mesoporous carbon of size less than 100 nm with reasonable photothermal and photodynamic activities is a challenging task. In this connection, the present paper reports synthesis of nitrogen-doped mesoporous carbon spheres (NMCSs) from five different copolymers of pyrrole and substituted aniline (-H, o-NH₂, m-NH₂, p-NH₂, and m-NO₂) using a soft template approach. It has been found that NMCSs synthesized from poly­(pyrrole-co-m-nitroaniline) show uniform mesoporous particles of size 80 nm, a photothermal conversion efficiency η of 52.7%, and an average ¹O₂ quantum yield of 20% under exposure of a 980 nm NIR laser. With a high η of 52%, a multifunctional nanodrug has been formulated by loading 5-Fu in NMCS. The overall drug-loaded NMC was encapsulated by thermosensitive DSPE-PEG to improve translocation of the particle in the cell and thermosensitive drug release. A reliable release of anticancer drug 5-Fu (78%) has been achieved in 50 h in lysosomal conditions under 980 nm laser exposure. This NMC-5-Fu-DSPE-PEG nanodrug produces reactive oxygen species and enhances the therapeutic effect in comparison with free drug under an NIR laser as verified in B16F0 melanoma cells.