Biomaterials control body’s immune response to reduce risk of dental implant rejection
NOTTINGHAM, UK: Artificial joints, stents and dental implants are among the most common devices that use biomaterials in order to restore function or replace damaged tissue. However, after the implantation of biomaterials in the body, a host reaction can occur which may result in implant failure. Now, researchers from the University of Nottingham’s schools of pharmacy and life sciences have discovered that the topography and chemical composition of polymer materials can be altered in order to create materials that control the body’s immune response. This finding could be applied to reducing the risk of the rejection of various medical devices, including dental implants.
Host reactions, including responses such as inflammation, foreign-body reaction and fibrous capsule development, are driven by the activation of immune cells—monocytes and macrophages—attaching to the implant surface. The topography of a material or implant is known to influence macrophage attachment.
“We are looking at ways to create materials that can be safely put inside the body without the immune system attacking it and causing rejection. To do this we are exploring materials that can control the immune response,” explained Prof. Amir Ghaemmaghami from the School of Life Sciences at the university and co-leader of the research. “We have used high throughput screening technology to examine how the topography and chemical properties of a material can be used to design ‘immune‐instructive’ surfaces for potential use in implants, which influence macrophage function and consequently the foreign-body responses to biomaterials,” he continued.
A high throughput screening approach was used to investigate the relationship between material topographies and immune cell attachment and behaviours for 2,176 different micro-patterns. The results indicated that micron-scale pillars ranging from 5–10 µm in diameter were key in driving macrophage attachment and that the density of the micro-pillars was crucial for controlling inflammatory reactions.
“It is exciting to have discovered these biomaterials that could be a real game-changer in the area of medical implants”
—Prof. Morgan Alexander, University of Nottingham
The research team also discovered immune-instructive polymer chemistries that successfully controlled the immune response in a preclinical rodent model. This was achieved through screening libraries of diverse polymers and identifying materials that control the behaviour of macrophages.
An artificial intelligence algorithm was used to model the relationships between the material chemistries and the cell responses they produced. These results suggested that different immune-instructive polymers attract different amounts of the protein adsorption which was key to the macrophage responses.
“These latest discoveries add to a wealth of materials research taking place at the University of Nottingham and it is exciting to have discovered these biomaterials that could be a real game-changer in the area of medical implants. Getting these materials used in a commercial product would be our ultimate aim for this research, there is still a way to go to get there but these discoveries are a significant step towards that,” said co-author Prof. Morgan Alexander from the School of Pharmacy at the university.
The research team has published its findings in two recent studies. The first study, titled “Immune modulation by design: Using topography to control human monocyte attachment and macrophage differentiation”, was published online on 28 April 2020 in Advanced Science, ahead of inclusion in an issue.
The second study, titled “Immune-instructive polymers control macrophage phenotype and modulate the foreign body response in vivo”, was published online on 1 May 2020 in Matter, ahead of inclusion in an issue.