Systematical investigation of in vitro molecular interaction between fluorescent carbon dots and human serum albumin

Abstract

Fluorescent carbon dots (CDs) have been widely applied in biological and biomedical applications due to their superior properties. Therefore, for any in vivo biomedical application, the thermodynamic and kinetic information of in vitro molecular interaction between CDs and human serum albumin (HSA) is very important and need to be elucidated deeply. In this work, in vitro molecular interaction between CDs and HSA was systematically investigated by spectroscopic techniques and electrochemical approaches. CDs with maximum emission of 437 nm were synthesized by microwave technique through a one-pot process. Some important thermodynamic and kinetic parameters were calculated, and the binding interaction between HSA and CDs was further explored by electrochemical approaches. The binding interaction of CDs with HSA was resulted from the complex formation of HSA–CDs. Hydrogen bonding and van der Waals interactions played major roles during HSA–CDs complex stabilization. The primary binding site of CDs was mainly located within site I (subdomain IIA) of HSA. The micro-environmental and conformational changes of HSA induced by CDs were investigated by multi-spectroscopic methods. These data suggested that the conformational change of HSA was significantly at secondary structure level and the biological activity of HSA was weakened dramatically in the present of CDs.