Protein-based photocatalyst uses blue light to selectively disinfect water
Although UV light is playing a significant role in destroying both water and surface bacteria, UV light can also harm good bacteria and even DNA.
Although ultraviolet (UV) light is playing a significant role in destroying both water and surface bacteria, UV light can also harm good bacteria and even DNA. Recognizing this disadvantage of UV light and the possible toxic effects of nanoparticle-based disinfection, researchers from the University of Cincinnati (Cincinnati, OH) have instead introduced a reactive oxygen-generating fluorescent protein called StrepMiniSOG (SMS) that can be made to bind to specific bacteria (when paired with specific antibodies) and produce hydrogen peroxide (H2O2) to selectively destroy only those bacteria when illuminated with blue light, leaving good bacteria and cellular structures intact.
Disinfection studies confirmed that targeting Listeria monocytogenes in a mixed culture of both E. coli and Listeria effectively removed the target while leaving the E. coli unharmed. After 30 minutes of exposure to 450 nm light, 80% of the Listeria were neutralized in solution using the SMS-antibody mixture and 99.99% were gone after 1.5 hours. Because the protein mixture is nontoxic and degrades with the chemical reaction to its targeted bacteria, it would be safe for human ingestion as well as general water and surface disinfection. In addition, the photocatalyst does not produce the carcinogenic disinfection by-products associated with chlorine disinfectants and can be used with a visible light source, enabling safe disinfection on surfaces like human skin. References: www.uc.edu/news/NR.aspx?id=24078 and http://dx.doi.org/10.1371/journal.pone.0162577.