The Principles of Antimicrobial Biomaterials for Prevention of Biofilm Infections

摘要

All biomaterials are at risk of infection, limiting their usefulness. The clinical consequences of some of these infections are severe and life-threatening. In fecting micro - organisms are usually endogenous. Once having reached the implant they must attach to become clinically relevant. All biomaterials become coated in a host - derived proteinaceous conditioning film, and most infecting micro - organisms possess surface attachment mechanisms specific for this film. After attachment, the microbes proliferate, eventually developing a biofilm. If prevention of biomaterial infection is to succeed, it must operate before the proliferation stage. Antibiotics expose the patient to adverse events and often fail to reach the implant surface, and a range of "antimicrobial" biomaterials has been developed to prevent biofilm infections. They must be active against the common infecting microbes, without removal too rapidly by fluid flow or obliteration by conditioning film. They must have sufficient duration of activity to cover the period of risk of their intended application, and they must be stable and sterilizable. They must not promote or give rise to resistance. These exacting requirements can be met in only a few instances. Generally, antimicrobial coatings do not afford a sufficient duration of activity for any other than short -term implants. Silver - processed devices do not perform well when properly tested in vitro, and are often disappointing in vivo, and the possible reasons for this will be discussed. Two clinically successful antimicrobial biomaterials will be presented and their remaining problems examined. Finally, strategies to avoid microbial resistance development associated with the use of antimicrobial biomaterials will be proposed.