Implants are devices made of biomaterials that are used to help repair or replace damaged tissues in the body to assist with healing. For example, implants are often used to stabilize bone fractures. However, many implants fail after being placed in the body because the body sees them as foreign bodies and creates a capsule around them to isolate them from the surrounding tissues.
goal
The foreign body response entails protein adsorption, rush of immune cells, and an extended inflammation that eventually leads to the deposition of fibrous capsule around the implant. This fibrous capsule has weak attachment to the implant and leaves the implant at high risk for premature failure. In this paper, the research team wanted to reduce he inflammatory response by changing the surface of the implants by adding different chemical groups. These surface treatments could be applied to implants to improve their integration with the surrounding tissue and ideally, extend their clinical lifetime.
methodology
The research team of Laura Stone and Emilie Buck used a chemical reaction that generates highly reactive compounds that can modify the surface of highly inert implant surfaces. They chose poly(styrene) as a model inert material and modified its surface with different chemical groups. Then, they evaluated the response of immune cells, known as macrophages, to the poly(sturene) modified by the different groups. They measured the level of genes and proteins in the immune cells to determine how strong they reacted to the different surfaces. Finally, the research team identified which proteins were adsorbed on the surfaces of the implants to better understand the mechanism underlying the changes in the behaviour of specific immune cells.
main findings
Experiments showed that having certain groups of atoms like the COOH groups on the implant surface activates the expression of proteins that decrease inflammation. In addition, the macrophages grown on surfaces containing COOH groups expressed genes and proteins associated with wound healing and the formation of new blood vessels.
take home message
Surface chemistry modifications can change the response of immune cells and may be able to reduce the inflammation observed around implants. Implants modified with COOH groups may improve integration within the surrounding tissue by reducing the inflammatory response and ultimately, reduce the risk of failure from poor integration.
