Implantable medical devices foreign body response

Inflammation, wound healing, foreign body response, and repair of implant sites are usually considered components of the general soft tissue response to biomaterials or medical devices. The extent or degree and temporal variations in these responses are dictated by the inherent biocompatibility characteristics of the biomaterial or medical device. Factors which may play a role in the soft tissue response include the size. 

Infection and foreign body response (FBR) are among other significant problems faced by long-term use of medical devices. The mechanism of bacterial adhesion is a very complex process. Bacterial adhesion involves initial reversible physicochemical interactions, followed by time-dependent irreversible molecular and cellular interactions (An and Friedman, 2000). Due to various physical forces, such as Brownian movement, van der Waals forces, and hydrophobic and electrostatic interactions, bacteria move to the implant surface. In the second phase, molecular and cellular interactions become predominant where bacteria attach irreversibly to the surface... 

Blood-contacting materials have to fulfill particular requirements, as they are immediately exposed to all host defense mechanisms of the body. Thus, the contact of blood with foreign surfaces induces several cascade reactions and activation phenomena. These complex and highly interconnected reactions potentially create clinically significant side effects in the application of medical devices (e.g., cardiovascular implants, extracorporeal circulation, catheters) and interfere with the success of the medical treatments [64]. In certain cases, even the formation of thromboemboli or systemic inflammatory reactions were reported to occur as a consequence of the activation of coagulation enzymes and thrombocytes and/or the activation of the complement system and leukocytes (immune response) at the biointerfaces of the applied materials [65]. 

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