Engineered carbon-based quantum dots: a next-generation nanomedicine for the therapy and diagnosis of infectious diseases.

Infectious diseases are a major global health issue despite the development of antibiotics and chemotherapy. There is an unmet need for the development of novel therapeutic and diagnostic agents to combat emerging and multi-drug-resistant microorganisms. To overcome these issues, carbon-based quantum dots (QDs), i.e., carbon quantum dots (CQDs) and graphene quantum dots (GQDs), can be an alternative approach due to their diverse and distinct properties, such as chemical inertness, low toxicity, biocompatibility, and photostability. Engineered QDs (EQDs) prepared by integrating various moieties through doping, functionalization, surface passivation, or combination with antimicrobial substances have vast biological applications in the management of infectious diseases. The current review aims to comprehensively discuss the recent progress on pharmacological mechanisms and detection strategies of native QDs (CQDs and GQDs), and EQDs against a wide range of infectious disease-causing pathogens, namely, bacteria, viruses, fungi, and parasites. The major mechanisms of their action involve cell wall/membrane disruption, replication and transcription inhibition, excessive ROS generation, immune response pathway activation, and synergistic interactions with antimicrobial agents. In addition, EQDs integrated diverse detection strategies, including optical, nucleic acid, immune, lateral flow assay, electrochemistry, emphasizing their potential use as sensitive probes for the rapid monitoring of pathogens in biological and environmental samples. Finally, the evolving scenarios of regulatory requirements, potential toxicity, and challenges in their clinical translation are addressed in this review. The current review will certainly be useful in advancing research activities for developing new affordable antimicrobial drugs and diagnostic agents using native QDs/EQDs.