The implantation of a synthetic mesh is a standard and common procedure for a patient with a hernia. However, it brings the risk of post-surgical infection caused by bacterial colonization on the surgical mesh surface (see image) that can be difficult to treat. To solve these issues, Ignacio de Miguel and co-workers from Spain have now investigated the use of a light-induced disinfection scheme that exploits the heating of plasmonic gold nanoparticles (GNPs) (Nano Lett. https://doi.org/10.1021/acs.nanolett.9b00187; 2019).
The idea is that the surface of the surgical mesh is chemically modified to anchor GNPs tuned to be resonant at the near-infrared wavelength of 800 nm, inside the first transparency window of biological tissues (650–1,100 nm). On illumination with a laser with an emission wavelength that matches the main absorption peak of the GNRs, light-induced heating occurs and the local temperature change damages the biofilm produced by bacteria. Unlike antibiotics, because this damage is caused by a physical means, the bacteria cannot adapt to the treatment and become resistant. Furthermore, the near-infrared irradiation can be performed repeatedly after mesh implantation as many times as necessary.
A proof-of-principle experiment was performed with GNP-anchored meshes deliberately infected with Staphylococcus aureus bacteria. The Spanish scientists then systematically changed the irradiation conditions (energy fluence and the pulse duration) and evaluated the impact on the number of bacteria. When the mesh was illuminated with a fluence of 15 J cm–2 and pulse duration of 300 ms, the number of bacteria decreased by 97.6%.
The scientists believe that the main mechanism behind the elimination of the biofilm was its loss of adhesion from the mesh, most likely resulting from the denaturation of adhesive exopolysaccharides.
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Horiuchi, N. Plasmon-enabled disinfection. Nat. Photonics 13, 308 (2019). https://doi.org/10.1038/s41566-019-0429-z