Binding effect of tyrosine-based chiral carbon dots on human serum albumin and lysozyme

Recently, chiral carbon dots (CCDs) have generated significant interest in biological fields such as biosensing, bioimaging, and drug delivery, due to the combination of inherent chirality and nanoscale size. Here, spectroscopic methods have been used to monitor the interaction between human serum albumin (HSA) and lysozyme (LYZ) with CCDs. Long-wavelength emission CCDs (LWE-CCDs) were synthesized using L/D-tyrosine (L/D-Tyr) and o-phenylenediamine (o-PDA) through a facile and one-step solvothermal approach. Two mentioned proteins interacted with L- and D-CDs and the results of secondary structure studies revealed that proteins preserve their native structure while having a small increase in their compactness. Furthermore, studies on the tertiary structure indicated more flexibility and the possibility of disorder in the hydrophobic regions of HSA, while LYZ appeared to become more rigid. Generally, the L- and D-CDs have more effect on the secondary and tertiary structures of HSA and LYZ, respectively. In addition, the interaction of L/D-Tyr (chiral precursor) with proteins was studied using molecular docking to explain the different effects of the CCDs on HSA and LYZ, and the obtained results are almost consistent with the results of experimental tests. This research offers new perspectives on the synthesis of LWE-CCD and the impact of their chirality on protein-nanoparticle interactions. Studying the action of CCDs at the molecular level will help researchers to choose suitable isomers to apply in biological applications.