Carboxyl-functionalized multifunctional red-emitting carbon quantum dots as an ideal biomaterial

Carbon quantum dots (CQDs) have been developed into a popular nanomaterial due to their abundant surface state, good biocompatibility, and excellent antimicrobial properties. However, CQDs which combine multiple functions such as red emission, good antibacterial, and excellent pH-sensitive have been rarely reported. In this work, a carboxyl-functionalized red fluorescent CQDS (R-CQDs) with maximum peak at 664 nm and an absolute photoluminescence quantum yield (PLQY) of 28.5% were prepared, showing excellent photostability and extraordinary salt tolerance. In antimicrobial application, R-CQDS featured good antibacterial activity by generation of reactive oxygen species (ROS), indicating excellent photodynamic antimicrobial ability. In addition, R-CQDS showed fine pH-sensitivity, which can be a potential pH sensor to monitor the wound pH in real time. Also, the real potential application of R-CQDS for cell imaging was demonstrated. In summary, we offered a R-CQDS with good antibacterial and pH-sensitive as a potential nanomaterial for pH monitoring and antimicrobial of wound, shedding light on the biomedical field. .