Green one-pot synthesis of luminescent carbon-polymer dots for drug delivery and anticancer chemo-photothermal therapy

Chemo-photothermal therapy (chemo-PTT) is a challenging topic to improve cancer treatment. Herein we report an unprecedented example of biocompatible photo-responsive carbon-based polymer dots (CPDs-PNM) obtained by a one-pot thermal process from poly(N-isopropylacrylamide) (PNM) without using organic solvent and additional reagents (Figure 1). The CPDs-PNM, characterized by spectroscopic and microscopic techniques, exhibited high photothermal conversion efficiency, lower critical solution temperature behavior, and good curcumin and cytarabine (AraC) loading capacity. The drug release triggered by green-light excitation was demonstrated by spectroscopic techniques and the release mechanism related to the polymer conformational change was well supported by modeling simulation calculations. Cellular uptake of empty and AraC-loaded CPDs-PNM was evidenced by laser scanning microscope experiments. The CPDs-PNM showed no effect on neuroblastoma cell viability, whereas the CPD-PNM/AraC adduct upon green-light irradiation showed significant toxicity, higher than AraC alone. The luminescent, photothermal-responsive CPDs-PNM can represent a new drug delivery system for anticancer chemo-PTT. They combine the benefits of synergistic drug/hyperthermia effects with the light-controlled spatio-temporal drug release, thus limiting the cytotoxic effects to the irradiated cells while sparing healthy cells.