Exploration of copper-cysteamine nanoparticles as a new type of agents for antimicrobial photodynamic inactivation

Copper-cysteamine (Cu-Cy) nanoparticles (NPs) are a new type of sensitizers that can be activated by UV light, X-rays, microwaves and ultrasound to produce reactive oxygen species for cancer treatment. Here, for the first time, we explored Cu-Cy NPs for bacteria inactivation by treating gram-positive bacteria (methicillin-resistant Staphylococcus aureus and Enterococcus faecalis) and gram-negative bacteria (Escherichia coli and Acinetobacter baumannii), respectively. The results show that Cu-Cy NPs are very effective in killing gram-positive bacteria but are quite limited in killing gram-negative bacteria yet. The major killing mechanism is cell damage by singlet oxygen and Cu-Cy NPs are potential agents for bacteria inactivation.