By attaching to surfaces such as contact lenses, water pipes, hip replacements and food packaging, they can cause irritation, disease, immune rejection and food poisoning. Now a team at Harvard University and Medical School have made polymer films many times better at resisting bacterial attachment than the materials currently used for medical implants 1 . George Whitesides and his co-workers have come up with a new way to tailor a surface so that it resists the attachment of bacteria. Their coating is a composite of gold, small organic molecules and polymers, constructed one molecular layer at a time.
Bacteria latch onto a surface by attaching to tacky proteins.
One surface to which proteins cannot stick easily, polyurethane, is already widely used to prevent bacterial contamination. Being tough and flexible, polyurethane is suitable for applications such as synthetic blood vessels. Coatings of the polymer polyethyelene glycol also help to cut down protein adsorption on biomedical devices. But the Harvard group were searching for something better, and more rationally designed. They began with a thin layer of gold.