“…Carbon dots (CDs) are carbon nanomaterials featured with high fluorescence stability, good biocompatibility, low toxicity, easy preparation, and wide applications, such as fluorescence imaging, − biochemical analysis, − photocatalysis, , and cancer therapy. , Recently, CD-based hypotoxic antimicrobial materials have drawn extensive attention from the scientific community. For instance, polyethylenimine (PEI), as a cationic polymer with many primary, secondary, and tertiary amino groups, has been popularly used in drug delivery, gene transfection, and antibacterial applications. − Due to the strong penetration and disruption ability of the positively charged PEI to bacterial cell membranes, the PEI-functionalized CDs provide candidates for the fabrication of antibacterial nanomedications. − However, despite very promising capabilities, some cationic CD-based antibacterial nanomedications in clinical treatment still face a critical issue that the higher concentrations are required to eliminate Gram-negative bacteria compared to that for Gram-positive bacteria, which accordingly address safety concerns. − Hence, constant efforts have been devoted to improving the antibacterial efficacy of cationic CD-based antibacterial nanomedications, particularly against Gram-negative bacteria.…”