Theranostic carbon dots ‘clathrate-like’ nanostructures for targeted photo-chemotherapy and bioimaging of cancer

Abstract

Abstract The drug delivery application of carbon-based quantum dots is a new platform in the medical field. We report a unique morphological structure called carbon-dots clathrates (C-dots CL ) conjugated with folic acid (FA) for targeted delivery of methotrexate (MTX), an anti-cancer drug under physiological conditions followed by photothermal (PTT) and photodynamic (PDT) treatment on cancer cells. Under physiological milieu, the C-dots CL –MTX–FA complex are pH-dependent and it can control release the anti-cancer drug in vitro . Furthermore, in vivo studies were also performed by using genetically-induced pancreatic cancer model to comprehend the in vivo pharmacokinetics and tissue distribution pattern of C-dots CL –MTX–FA complex. The results demonstrated that the CQD was able to deliver high concentration of MTX in tumour tissues in contrast to the non-tumour tissues. The impact of near-infrared (NIR) laser (1064 nm; Nd-YAG) on the CQDs system was found to be extremely effective for the rapid release of MTX in tumour tissues. The generation of reactive oxygen species (ROS) by C-dots CL upon irradiation of NIR laser was evaluated using flow cytometry. After conjugation with the C-dots CL , the half-life of the MTX drug (t 1/2 ), elimination constant (K el ), area under the curve (AUC) was drastically improved to prove the efficacy of C-dot CL as a powerful drug vehicle. This study has significantly improved the cancer theranostics research using C-dots CL to act as a multi-functional nanomaterial for imaging and as a drug delivery agent.