Near-IR quantum dot (BagQD) as fluorescent sensor for live-cell imaging and in-vivo antibacterial photocatalytic therapy (APT).

The development of multitasking agents that can sense, as well as damage multidrug-resistant (MDR) bacteria with no growth, is the need of the hour to overcome the increased mortality associated with antibacterial resistance. Toward this end, to overcome the limitation of organic dyes as fluorescence probes, and other developed quantum dots (QD), we present new of its kind near infrared type-I (NIR-I) CdSe/ZnSe/FeTiO3-based perovskite quantum dot, BagQD, for fluorescence-guided selective bacterial imaging-sensing and permanent disinfection. BagQD possesses unique photodynamic and photophysical properties of the near-infrared NIR-I biological window. The excellent electronic transitions of BagQD resulted in efficient quantitative fluorescent sensing-imaging of gram-positive (G+ve) as well as gram-negative (G-ve) bacterial pathogens, and complete in-situ and in-vivo disinfection/elimination of pathogenic bacteria without regrowth via damaging bacterial cell wall and cellular DNA, by ROS generation during photocatalysis. The material cytotoxicity study showed no harm to the human cell line. Moreover, the therapeutic application of BagQD on in-vivo mice skin wound infection, revealed the generation of hair follicles and epithelization within 6-8 days. Thus, BagQD serves as a new alternative to antibiotics and a smart nanomedicine that can uphold the hope in revolutionizing diagnostics and clinical avenues.