Photonics

Invented approximately 50 years ago, surgical medical meshes have become key elements in the recovery procedures of damaged-tissue surgeries, the most common being hernia repair. When implant within the tissue of the patient, the flexible and conformable design of these meshes helps hold muscles tight and allows patients to recover much faster than through the conventional surgery of sewing and stitching.

Patient’s body carries

However, the insertion of a medical implant in a patient’s body carries alongside the risk of bacterial contamination during surgery and subsequent formation of an infectious bio film over the surface of the surgical mesh. Such biofilms tend to act like a plastic coating, impeding any sort of antibiotic agent to reach and attack the bacteria form on the film in order to stop the infection.

Thus, antibiotic therapies, which are time-limited; so will fail against these super resistant bacteria; also the patient could end up in recurring or never-ending surgeries that even lead to death. As a matter of fact, according to the European Antimicrobial Resistance Surveillance Network (EARS-Net); so in 2015 more than 30,000 deaths in Europe were linked to infections with antibiotic-resistant bacteria.

Through an ongoing collaboration since 2012, the team of researchers at ICFO and B. Braun Surgical, S.A., develop a medical mesh with a particular feature: the surface of the mesh was chemically modify to anchor millions of gold nanoparticles. Why? Because gold nanoparticles have prove to very efficiently convert light into heat at very localize regions.

Long term stability

They test the meshes to ensure the long-term stability of the particles, the non-degradation of the material, and the non-detachment or release of nanoparticles into the surrounding environment (flask). So they were able to observe a homogenous distribution of the nanoparticles over the structure using a scanning electron microscope.

They discover the following: Firstly, they saw that illuminating the mesh at the specific frequency would induce localize surface plasmon resonances in the nanoparticles a mode that results in the efficient conversion of light into heat, burning the bacteria at the surface. Secondly, by using a fluorescence confocal microscope; so they saw how much of the bacteria had died or was still alive.

For the bacteria that remain alive, they observe that the biofilm bacteria became planktonic cells; so recovering their sensitivity or weakness towards antibiotic therapy and to immune system response. For the dead bacteria, they observe that upon increasing the amount of light deliver to the surface of the mesh; so the bacteria would lose their adherence and peel off the surface.

As Director of Research and Development of B. Braun Surgical, S.A. Dr. Pau Turon explains, “our commitment to help healthcare professionals to avoid hospital; so relate infections pushes us to develop new strategies to fight bacteria and biofilms. Additionally, the research team is exploring to extend such technology to other sectors where biofilms must be avoided.”