Neutral red/carbon dots photodynamic disinfectant spray for sports mouthguards cleaning and perishable foods preservation

Bacterial contamination of medical devices and food poses critical threat to mankind's health. Although some antibiotics can kill bacteria, their mis/overuse in healthcare and agriculture has brought about serious bacterial antibiotic resistance. Thus, developing a convenient and rapid sterilization method becomes increasingly important. Herein, the nanocomposite NR@CDs was synthesized by the assembly of neutral red (NR) with carbon dots (CDs). Compared with NR, NR@CDs has stronger reactive oxygen species (ROS) generation ability. NR@CDs can photodynamically destroy both gram-positive and gram-negative bacteria efficiently, and the minimum inhibitory concentration (MIC) is 45 μg mL. NR@CDs spray is an eco-friendly sterilizing agent, with favorable biocompatibility and water-washability properties. Just 1 min of irradiation, NR@CDs spray can quickly and accurately kill the bacteria on the surface of the mouthguards (MGs). As the NR@CDs aqueous solution sprays on cherries, it can effectively prolong the quality guarantee period of perishable foods. The present work provides an innovative strategy to solve the global bacterial contamination and antibiotic resistance problems.