Metallic and Non-Metallic Quantum Dots as Potent Antibacterial Agents

The emergence of antibiotic-resistant bacteria poses a critical public health issue worldwide, which demands the development of novel therapeutic agents as viable alternatives to antibiotics. The advent of nanoscience and technology offers the synthesis of several potential anti-microbial agents that are effective against both Gram-positive and Gram-negative bacterial strains. One such nanoscale material that fascinated researchers due to its unique optoelectronic properties is Quantum Dots (QDs). Moreover, these are found to be highly bactericidal, even against resistant bacterial infections. Thus, a significant number of researches have been going on globally to employ QDs as potent bactericidal agents alone or in combination with antibiotics. Studies demonstrated that intracellular uptakes of QDs elevate the level of reactive oxygen species (ROS) inside the cells, which turns-on cascades of intracellular events that cause damage to DNA and proteins. However, the inherent reactive nature of these metallic and semiconductor QDs raises huge concern for translational research as these are found to be cytotoxic and non-biocompatible. Moreover, the human body does not have a proper sequester mechanism to remove these metallic ions from the body, which limits its direct applications. Recent progress in this line of interest has focused on developing non-metallic quantum dots, such as carbon dots (CQDs) and Black Phosphorus quantum dots (BP QDs) which showed less toxicity and immunogenicity suitable for real-life applications. Therefore, in the present chapter, we are going to discuss the recent development of bactericidal QDs and various types of surface functionalization illustrated recently to increase biocompatibility.