In vitro analysis of a nanocrystalline silver-coated surgical mesh

One million nosocomial infections occur each year in patients with prosthetic devices. We analyzed a polypropylene mesh coated with nanocrystalline silver particles (NCSP) as a means of preventing such infections.

Nanocrystalline silver was applied to polypropylene mesh using physical vapor deposition in three doses: low (0.31 mg/cm(2)), medium (0.64 mg/cm(2)), and high (1.13 mg/cm(2)). The zone of inhibition (ZOI) test was conducted by incubating either uncoated polypropylene mesh (UM) or silver-coated mesh (CM) with and without various amounts of bovine serum albumin (BSA) and then on agar plates with Staphylococcus aureus and calculating the ZOI. The bactericidal effects of the NCSP-coated meshes were assessed by incubating either UM or CM in medium with S. aureus and performing serial dilutions at 4 and 8 h. Scanning electron microscopy (SEM) was used to examine the surface of UM and CM with and without bacterial incubation.

There was an increasing ZOI for low-, medium-, and high-dose CM and no ZOI for UM (p < 0.001 for all CM compared with UM). Incubating the mesh with various amounts of BSA produced persistent ZOIs with the medium- and high-dose CM; however, the low-dose CM became attenuated by such treatment, with no ZOI being seen with meshes incubated in 10% BSA. All concentrations of CM were bactericidal, as no bacteria grew at 8 h of incubation. The SEM images showed clusters of S. aureus on the surface of UM and no clusters on CM.

The CM demonstrated significant bactericidal activity compared with UM. Nanocrystalline silver particles may decrease the incidence of postoperative prosthetic mesh infections and be useful as a coating for other prosthetic materials.