Low temperature synthesis of yellow-green emission carbon dots with excellent antibacterial activity for Escherichia coli and Methicillin-resistant Staphylococcus aureus

Abstract

Human life is seriously threatened by the development of antibiotic-resistant microorganisms. The most promising antibacterial agents for dormant pathogenic among the range of nanomaterials are carbon dots. This work proposes a fast and environmentally friendly method for preparing yellow-emission carbon dots (YCDs), which could be completed within 30 min at 80 °C by using ascorbic acid and cetylpyridinium chloride monohydrate as precursors. Crucially, the obtained YCDs could be easily internalized by bacteria and emit bright yellow-green light inside the cells due to the small size (3.9 ± 0.6 nm) and large stokes shift (161 nm). Additionally, the YCDs display excellent effectiveness against pathogenic bacteria, especially for Gram-negative and resistant Gram-positive bacteria. The minimum inhibitory concentration for methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli are 1.25 and 5 μg mL⁻¹, respectively. Furthermore, results demonstrate that the excellent antibacterial ability of YCDs is attributed to a combination of the hydrophobic of alkyl chain, oxidative damage and electrostatic interaction. Overall, our work provides an environmentally friendly and low-cost method to prepare the yellow-green emission carbon dots with strong antibacterial activity against resistant bacteria.