Sticky surfaces

Whether bacteria stick to surfaces or not depends partly on how stiff those surfaces are. Armed with that knowledge, MIT engineers have created ultrathin films made of polymers that could be applied to medical devices that go inside the body, such as stents and other cardiac implants.

The researchers, who described their work in a paper in an upcoming issue of Biomacromolecules, found they could control the extent of bacterial adhesion to surfaces by manipulating the mechanical stiffness of polymer films called polyelectrolyte multilayers. Thus, the films could be designed to prevent accumulation of hazardous bacteria or promote growth of desirable bacteria.

'All other factors being equal, mechanical stiffness of material surfaces increases bacterial adhesion,' said Krystyn Van Vliet, the Thomas Lord Assistant Professor of Materials Science and Engineering.

Van Vliet and her colleagues found the same trend in experiments with three strains of bacteria: Staphylococcus epidermidis, commonly found on skin, and two types of Escherichia coli.