Guanidinium-Functionalized Carbon Dots: An Efficient Antibacterial Agent against Multidrug-Resistant ESKAPE Pathogens

The rise of multidrug-resistant (MDR) bacteria poses a substantial challenge in clinical settings, particularly with the increasing prevalence of ESKAPE pathogens (E. faecium, S. aureus, K. pneumoniae, A. baumannii, P. aeruginosa, and E. coli) as critical MDR bacteria. These ESKAPE pathogens have the capability to undermine antibiotic treatments, leading to a high incidence of drug resistance. However, the development of efficient antibacterial agents against ESKAPE pathogens is still in the bottleneck. Herein, the first example of antibacterial carbon dots against ESKAPE pathogens was reported. Onion powder-based carbon dots were melted with poly­(hexamethylene biguanide) hydrochloride (PHMB) to obtain guanidinium-functionalized carbon dots (GCDs), which exhibited satisfactory antibacterial activity against all the tested bacteria, including both Gram-positive and Gram-negative bacteria, and even ESKAPE pathogens. The efficient antibacterial ability of GCDs derives from the rupture of the bacterial cell membrane and elevated ROS levels. Safety assessments revealed that GCDs neither trigger detectable drug resistance nor exhibit any cytotoxic effects. Furthermore, GCDs effectively promoted wound healing without observable adverse reactions of mixed MDR bacteria-infected wounds in rats. The GCDs also showed excellent long-term stability. These findings indicate that GCDs hold promise as an efficient antibacterial agent for the treatment of MDR strain-caused clinical infected-wound healing.