Green preparation of carbon quantum dots and its silver nanoparticles composite against carbapenem-resistant Acinetobacter baumannii

Nowadays, one of the biggest concerns for healthcare all over the world is the presence of antibiotic-resistant bacteria. Among them, carbapenem-resistant Acinetobacter baumannii (CRAB) is considered as “red alert” human pathogen and ranked as a number one critical pathogen by the World Health Organization (WHO) in the list of the global priority antibiotic-resistant bacteria. For the treatment of disorders caused by bacterial infections, effective antibiotic-free materials must be synthesized. For the first time, a large-scale, environmentally benign approach of producing silver nanoparticles was investigated in this study employing carbon quantum dots as a reducing and stabilizing agent.Through hydrothermal carbonization, it was created from the excellent, benign, and biocompatible substance chitosan. The CQDs and CQDs/AgNPs nanocomposites were characterized by UV–Vis, TEM, XRD, PL, and FT-IR. The synthesized CQDs and nanocomposite had spherical or nearly spherical particle sizes of around 4.6 and 25 nm, respectively. With a minimum inhibitory concentration (MIC) of 100 g/mL and maximum inhibition zones of 15 mm on CRAB, the synthesized CQDs/AgNPs nanocomposite demonstrated excellent antibacterial activity against tested antibiotic-resistant bacteria. Additionally, the created nanocomposite may be kept in storage for up to two years without clumping together and is appropriate for commercial production when exposed to gamma radiation at a dose of 50 kGy. Such researches are crucial in the demonstration of therapeutic importance of new materials in healthcare application.