One-Step Synthesis of Si-Doped Carbon Dots with Antibacterial Activities

Abstract— Drug-resistant pathogens are seriously threatening global public health. It is urgent to discover new drugs that can effectively inhibit drug-resistant bacteria. Carbon quantum dots (CQDs), as a good antibacterial agent, have gained considerable interest due to their green synthesis method and low toxicity. In this work, the Si-doped CQDs with bright blue fluorescence are prepared by one-step hydrothermal method using glycyrrhizic acid and methyltrimethoxysilane. The average particle diameter of Si-doped CQD with emission at 420 nm is found to be 2.10 nm. The Si-doped CQDs exhibit a good antibacterial activity against Escherichia coli and Staphylococcus aureus with MIC of 1.25 mg/mL, but it does not show selectivity. Furthermore, the antibacterial mechanism of Si-doped CQDs suggest that Si-doped CQDs destroy the normal morphology of bacteria by generating ¹O₂ and enter the interior of bacteria to produce antibacterial effects. The present study provides a strategy for the preparation of CQDs from a medicinal plant with antibacterial activities against two common pathogens.