Gold-oxoborate nanocomposites and their biomedical applications.

A novel inorganic nanocomposite material, called BOA, which has the form of small building blocks composed of gold nanoparticles embedded in a polyoxoborate matrix, is presented. It is demonstrated that cotton wool decorated with the BOA nanocomposite displays strong antibacterial activity toward both Gram-positive and -negative bacteria strains. Importantly, the modified cotton does not release any toxic substances, and the bacteria are killed upon contact with the fibers coated with the BOA. Toxicity tests show that the nanocomposite--in spite of its antiseptic properties--is harmless for mammalian cells. The presented method of surface modification utilizes mild, environmentally friendly fabrication conditions. Thus, it offers a facile approach to obtain durable nontoxic antiseptic coatings for biomedical applications.