Exploring the binding of carbon dots to calf thymus DNA: From green synthesis to fluorescent molecular probe

Carbon dots (CDs) have been widely applied in bioimaging, drug delivery and nanomedicine. In this study, the interaction binding mechanism of CDs with calf thymus DNA (ctDNA) has been investigated. A bottom-up synthetic route was selected at low temperature and a one-pot green synthesis of CDs was applied with ascorbic acid as carbon precursor and a water phase reflow at 90 degrees C under stirring for 3.5 h. The resulting as-synthesized CDs exhibited a green-yellow color, different than what has already been reported for this product with ascorbic acid as carbon precursor. The quantum yield of CDs was 13.3% and the fluorescence decay was 3.19 ns. Analytic methods such as UV-vis absorbance, fluorescence spectroscopy, circular dichroism spectroscopy and electrochemical approaches were used to study the binding mechanism between the CDs and ctDNA. Overall, the results indicated that the binding mode between CDs and ctDNA was intercalation. Moreover, the CDs exhibited specific properties that may be useful in the replacement of other, often toxic fluorescent dyes that are commonly used for organ imaging. CDs may therefore represent a promising fluorescence probe of ctDNA. (c) 2018 Elsevier Ltd. All rights reserved.