Researchers from the Institute of Physical Chemistry of the Polish Academy of Sciences report that silver nanoparticles formed with tea extracts significantly enhance antibacterial and antifungal activity. The findings appeared in the scientific journal Nano Advances (NanoAdv) as part of a study on alternative strategies to counteract pathogens without relying on traditional antibiotics.
The investigation aimed to identify practical methods for reducing infectious agents while avoiding antibiotic resistance risks. The team explored the combination of tea components with silver nanoparticles, leveraging the known antimicrobial properties of both substances. Three widely consumed teas served as stabilizing agents in the experiments: black tea, green tea, and the Chinese Pu-erh tea.
Initially, tea-assisted silver nanoparticles were tested against both gram-negative bacteria such as Escherichia coli and gram-positive bacteria like Enterococcus faecium. The researchers then evaluated how these nanoparticles interacted with the pathogens and compared their performance to commercially available antibiotics.
Following the established protocol, the experiments identified the concentrations and particle compositions that produced the strongest antibacterial effects. The results showed a reduction in bacterial cell counts, with Enterococcus experiencing up to a 25% decrease and E. coli up to a 90% decrease under optimized conditions.
In addition to antibacterial activity, green-synthesized silver nanoparticles demonstrated antifungal effects. The studies observed an 80% reduction in viable cells of the fungus Candida auris, which is linked to candidiasis, and an approximately 90% decrease in cells of Cryptococcus neoformans, the organism responsible for cryptococcosis.
According to co-author Mateusz Wdowiak, the silver nanoparticles produced with tea extracts showed stronger antibacterial properties than silver nanoparticles prepared without tea. This allowed effective use at lower doses, about 0.1 mg/ml, and, in some cases, a synergistic effect between the tea components and the silver nanoparticles at the same concentration. The researchers noted that this combination achieved higher efficacy than the antibiotic ampicillin in tests conducted over a relatively short exposure period of three hours (NanoAdv study attribution).
Earlier work in this area has also highlighted the practical value of combining natural substances with metal nanoparticles to combat microbial threats, underscoring the potential to reduce reliance on conventional antibiotics and expand the toolkit for infection control. While these findings are promising, the researchers emphasize the need for further studies to assess safety, stability, and performance in real-world applications across diverse environments and organisms (NanoAdv study attribution).
Overall, the report underscores a growing interest in green synthesis approaches that pair common tea varieties with silver nanoparticles. The resulting materials may offer enhanced antimicrobial capabilities and pave the way for new, lower-dose strategies to manage bacterial and fungal infections while addressing concerns about antibiotic resistance. The work contributes to a broader effort to explore sustainable and accessible options in microbial control, aligning with ongoing international investigations into alternative antimicrobial technologies (NanoAdv study attribution).