Implant-Associated Infections and Immune Reactions
As a result of progress in biomedical technology, it is now possible in many medical disciplines to replace the function of damaged or missing organs and tissues by using implants, thus considerably improving the patient's quality of life. However, implant-associated infections are still one of the most important challenges in modern medicine. These infections may lead to the loss of implant function, to the loss of the implant itself, or even - in some medical disciplines - to potentially fatal complications. These infections are caused when the implant surfaces are colonised by bacteria organised in complex communities - the so-called “biofilms”. This results in inflammation, accompanied by destructive changes in the surrounding tissue. It has not yet been possible to treat this effectively, as the bacteria in the biofilm are specifically organised within a protective matrix and their metabolism is modified.
Thus the objective of this module is to develop innovative implant surfaces for various medical disciplines, with both long-term anti-biofilm activity and good biointegration and then fulfil the clinically relevant requirements for patient specificity, control and stability. Approaches include physical functionalisation of the surface with modern laser-based procedures, as well as chemical functionalisation, including control and stability. Possible active substances include antibiotics for the patient's specific risk profile, as well as new active substances identified with an innovative screening procedure.
The developed surfaces are validated in special in vitro and in vivo test procedures. A complex screening procedure has been developed. Firstly, confocal laser microscopy and molecular biological procedures are used to select active surfaces. Secondly, these are analysed in a three dimensional model with respect to their ability to inhibit biofilms and their corresponding gene expression profiles. Thirdly, successful variants are tested more closely in in vivo infection models (dental and orthopaedic implants) specially developed for clinical problems. These models permit the simulation of a variety of different routes of infection - perioperative or haematogenic - and are performed in accordance with a defined and standardised plan, so that the results are reproducible. It is then possible to compare newly developed surfaces with each other or with standard implants, and to reach a conclusion about the implants' antibacterial activity and ability to prevent infections.
