Photothermal performance of a novel carbon dot and its conjugate with disulfiram for prostate cancer PC3 cell therapy - supplementary data

Aim: To develop and employ a copper, sulfur, nitrogen–carbon quantum dot (C,S,N-CQD) multifunctionalplatform for synergistic cancer therapy, combining chemotherapy and photothermal treatment within vitro cancer cell imaging. Materials & methods: Cu,S,N-CQDs were synthesized hydrothermally,loaded with disulfiram (DSF), and characterized through UV-Vis spectrophotometry, photoluminescence,Fourier-transform infrared spectroscopy, high-resolution transmission electron microscopy, dynamic lightscattering, x-ray diffraction and EDAX. Results: Cu,S,N-CQD exhibited 5.5% absolute fluorescencequantum yield, 46.0% photothermal conversion efficiency and excellent stability. The release of DSFloadedCu,S,N-CQD, photothermal performance, and IC50 on PC3 prostate cancer cells, were evaluated. Theimpact of cellular glutathione on nanocarrier performance was investigated. Conclusion: Cu,S,N-CQD asa photothermal agent and DSF carrier showed synergy (combination index: 0.71) between chemotherapyand photothermal therapy. The nanocarrier simultaneously employed for in vitro cancer cell imaging dueto its unique fluorescence properties.Plain language summary: Nanometer-scale particles can be used to treat and detect cancer in many ways.A type of nanoparticle was designed to attack cancer in two different ways. These nanoparticles – copper,sulfur, nitrogen–carbon quantum dots (C,S,N–CQDs) – were designed to both deliver a chemotherapydrug to cancer cells and act as a photothermal agent. This means that when light of a particular energyis shone on these particles, they heat up and can kill cancer cells. These C,S,N–CQDs loaded with thechemotherapy drug disulfiram were then tested on the prostate cancer cell line PC3. When a laser wasshone on these particles and they became excited, they reduced cancer cell viability both by releasing thedrug and heating up and killing the surrounding cells. These Cu,S,N-CQDs are also fluorescent, meaningthey can be used to image cancer cells in tests like these.