Antimicrobials From Silver And Egg Whites

Using the enzyme lysozyme from chicken egg whites as the sole reducing and nucleating agent, scientists have developed an environmentally friendly way to prepare microbicidal silver nanoparticles (ACS Nano, DOI: 10.1021/nn900079e). The new material combines the bacteria-bursting abilities of silver with the hydrolyzing power of lysozyme and could find use in wound dressings, topical creams, and antiseptic sprays. Researchers led by D. Matthew Eby and Glenn R. Johnson of the Air Force Research Laboratory at Florida's Tyndall Air Force Base prepared the material by combining lysozyme and silver acetate in methanol and then exposing the solution to light. The process "offers a simple, inexpensive, and passive method to generate large amounts of stable silver colloids," they note. Assays showed that the resulting lysozyme-silver nanoparticles inhibit the growth of Escherichia coli, Staphylococcus aureus, Bacillus anthracis, and Candida albicans. The particles also proved to be effective at fighting silver-resistant strains of Proteus mirabilis and a recombinant strain of E. coli that's impervious to silver and several antibiotics. Furthermore, Eby and Johnson's team found the nanoparticles to be nontoxic to cultured mammalian cells at concentrations that killed microbial strains.