Highly Effective Porous Antimicrobial Coatings

Antimicrobial surface coatings can be used to reduce the transmission of infectious diseases that are spread by contact. An effective coating should kill microbes in the time between users, which is minutes or less, and also continue to operate for an extended period. Fast killing is a transport problem, and our solution is a porous coating with the active material inside the pores. We use hydrophilic pores of dimensions 5-100 µm such that they infiltrate liquid droplets in seconds, and from there transport distances and times are short, defined by the pore size, rather than the droplet size. Our coating has two levels of structure: (A) a porous scaffold and (B) an antimicrobial coating within the pore structure containing the active ingredient. Two scaffolds are studied: stainless steel and poly(methylmethacrylate) (PMMA). The active ingredient is electrolessly-deposited copper. To enhance adhesion and growth of copper, a layer of polydopamine (PDA) is deposited on the scaffold prior to deposition of the copper. This porous copper coating kills 99.8% of <i>Pseudomonas aeruginosa</i> within three minutes, which is highly effective. Killing on this fast scale is appropriate for antimicrobial applications to prevent disease.