Biomaterials implant surfaces in the human body are prone to infection. These can develop through three distinctly different routes. Peri-operative contamination is the best documented route and usually causes early implant-related infection. Also immediate post-operative contamination can be a cause of early failure of a biomaterials implant. Late post-operative infections by spreading of organisms from infections elsewhere in the body, have been described as well to be a cause for implant-related infections and failure of the implant. Since a biomaterial-associated infection (BAI) is difficult to treat with antibiotics due to the protection offered by the biofilm mode of growth and intra-cellular sheltering or microorganisms, the fate of an infected implant often is removal, at great discomfort to the patient and costs to the healthcare system. Frequently even, the condition of a patient does not allow replacement surgery or removal of the implant or device. BAI can even be lethal when bacterial spreading throughout the body occurs. Whereas the infection rate of primary implants may be considered low (4-6% on average, depending on the implant type), infection rates in revision surgery are much higher and around 15% with huge discomfort to the patients and much higher costs than of primary placement. Furthermore, many implants are used in society translating the ‘low’ BAI percentages into large absolute numbers of patients worldwide.
Although mechanisms of bacterial and mammalian cell adhesion have been studied for decades, no ubiquitously accepted mechanism has been forwarded, and research is ongoing. An important general conclusion is, however, that bacteria often use the same adhesive sites in adsorbed protein layers on biomaterials implants and devices, as do mammalian cells. In order to put mammalian cells at an advantage in their attempts to integrate a biomaterials surface in the body versus microbial biofilm formation, we need a shift in paradigm for the development of biomaterials coatings from mono-functional (only non-adhesive to bacteria OR only adhesive to cells) to multi-functional (non-adhesive to bacteria AND adhesive to mammalian cells) ones. New insights in mechanisms of microbial and mammalian cell adhesion will be applied to develop multi-functional biomaterials coatings in combination with the Zernike Institute for Advanced Materials, Groningen, The Netherlands and Stevens Institute of Technology (Hoboken, USA) and other industrial and academic partners. Importantly, methods to evaluate biomaterials coatings, have only focussed on measuring one aspect of the coating performance at a time, while the shift in paradigm toward multi-functional coatings requires methods by which mammalian cell interaction on a biomaterial can be evaluated simultaneously with biofilm formation and preferably also with the reaction of immune components.
Such studies not only attempt to find solutions for the current problem of BAI, but also prepare for the future problem of infections related to porous, biodegradable scaffold materials as used in tissue engineering.