Investigation of functional selenium nanoparticles as potent antimicrobial agents against superbugs.

Developing highly effective antibacterial agents is important for a wide range of applications. However, the emergence of multiple antibiotic-resistant bacteria poses a public health threat. Many developed agents have limited practical application due to chemical instability, low biocompatibility, and poor long-term antibacterial efficiency. In the following study, we synthesize a synergistic nanocomposite by conjugating quercetin (Qu) and acetylcholine (Ach) to the surface of Se nanoparticles (Qu-Ach@SeNPs). Quercetin has been reported to exhibit a wide range of biological activities related to their antibacterial activity and acetylcholine as a neurotransmitter, which can combine with the receptor on the bacterial cell. Arrows indicate NPs and arrowheads indicate compromised cell walls. The study demonstrated how Qu-Ach@SeNPs exhibit a synergistically enhanced antibacterial performance against the multidrug-resistant superbugs (MDRs) compared to Qu@SeNPs and Ach@SeNPs alone. Qu-Ach@SeNPs are effective against MDRs, such as Methicillin-resistant Staphylococcus aureus (MRSA), at a low dose. The mechanistic studies showed that Qu-Ach@SeNPs attach to the bacterial cell wall, causing irreversible damage to the membrane, and thereby achieving a remarkable synergistic antibacterial effect to inhibit MRSA. The findings suggested that the synergistic properties of quercetin and acetylcholine enhance the antibacterial activity of SeNPs. In this way, Qu-Ach@SeNPs comprise a new class of inorganic nano-antibacterial agents that can be used as useful applications in biomedical devices. STATEMENT OF SIGNIFICANCE: The Qu-Ach@SeNPs have low cytotoxicity when tested on normal human cells in vitro. Qu-Ach@SeNPs are effective against MDRs, such as Methicillin-resistant S. aureus (MRSA), at a low dose. Importantly, Qu-Ach@SeNPs showed no emergence of resistance. These results suggest that Qu-Ach@SeNPs have excellent antibacterial activities. These agents can serve as good antibacterial agents against superbugs. Our data suggest that these antibacterial agents may have widespread application in the field of medicine for combating infectious diseases caused by MDRs, as well as other infectious diseases.