University College Dublin –
From prosthetic devices to dental implants to catheters, biomedical implants are common procedures. Yet, there’s a risk they could get infected. At best, a bacterial infection caused by a medical implant might lead to a regimen of antibiotics, but at worst could require surgical intervention. New research suggests infection risks could decrease through integrating graphite nanoplatelets, which kill bacteria, on the surface of implants.
Bacterial infections are caused when biofilm forms on the surfaces of implants. Biofilm is formed when bacteria which travels in bodily fluids settles on the surfaces on biomedical devices. The most common biofilm infections are caused by Staphylococcus aureus and Staphylococcus epidermidis. These are estimated as causing up to 50 percent of prosthetic heart valve infections and up to 70 percent of biofilm catheter infections. Further, biofilms cause up to 80 percent of microbial infections in humans.
At the Chalmers University of Technology, a team of researchers found that by integrating an implant surface with about 15 to 20 percent graphite nanoplatelets, they could effectively reduce the risk of biofilm formation. The nanoparticles make it difficult for bacteria to attach to implant surfaces by damaging the bacterial cell membrane.
Previously, the researchers from Chalmers investigated the use of graphene spikes to prevent infection. They showed that a layer of vertical spikes made from graphene were effective in slicing up any bacteria that settled on the surface of an implant while leaving human cells unharmed. Though horizontally integrated graphene had no antibacterial effect, the researchers found the vertical spikes were most effective at between 60 nanometers and 100 nanometers tall. For reference, a nanometer is one-billionth of a meter.
Last year, researchers at the University College Dublin looked to solve the problem of implant infections by killing bacteria on antibacterial coated titanium-based orthopedics with remotely activated near-infrared light (NIR). When the NIR is shone through soft tissue onto titanium implants, the antibacterial coating is heated to 50 degrees Celsius, a temperature which kills bacteria without harming human tissue. They showed the NIR activated coating was up to 95 percent effective in disrupting S. aureus biofilm formation.
At Chalmers, researchers reported that graphite nanoplatelets are effective at killing 99.99 percent of the bacteria which settled on implant surfaces. Additionally, producing graphite nanoplatelets is a more cost-effective option than the previously researched graphene spikes.
Graphite nanoplatelet integrated surfaces also pose a promising solution for long-term biomedical applications as they don’t have to be cleaned or replaced for extended periods of time.