Mitigating the foreign body response through ‘immune-instructive’ biomaterials

ObjectivesBiomaterials are routinely used in clinical applications. A key to the clinical success of implanted biomaterials is not eliciting detrimental immune responses. In this article, we provide an overview of immune responses to biomaterials, along with biomaterial-based approaches to mitigate the adverse host reactions while supporting pro-healing immune responses. We also review existing in-vitro models used to assess the biocompatibility of biomaterials.Key findingsOnce implanted, biomaterials are often detected as foreign bodies by the immune system, triggering detrimental immune responses. Such responses could damage host tissues and impair the function of implanted materials or devices. Therefore, there is substantial interest in developing new materials and tools with the ability to modulate immune responses to support tissue regeneration and healing processes. However, the bioengineering of immune responses through biomaterials requires detailed understanding of how the immune system typically responds to foreign materials. This knowledge can inform designing materials with bio-instructive chemistries and/or surface attributes. In this review, first we briefly discuss basic aspects of the foreign body response followed by different strategies for developing ‘immune-instructive’ biomaterials, models to test their efficacy and examples of their clinical applications.ConclusionsPromising progress has been made in the field of biomaterial engineering however, how different immune cells interact with biomaterials is yet to be fully elucidated. A better understanding of cell-material interactions, and particularly the impact of inter-individual variations, will allow the development of new generation of more personalised ‘immune-instructive’ biomaterials and medical devices to modulate immune responses towards anti-inflammatory and pro-healing phenotypes