# Novel Approaches to Combat Medical Device-Associated BioFilms
## 3 Novel Approaches to Combat Medical Device-Associated Biofilms
### Surface Modification
Therefore, they have great potential in the application of indirect restoration and implant abutment [151]. Antiadhesion coatings have also been realized by changing the physical and chemical properties of surfaces so that the bacteria no longer adhere easily. Hydrophoin has been used to coat different medically relevant materials and has been shown to be effective in preventing biofilm formation by _S. epidermidis_ on polystyrene surfaces through the formation of a self-assembled amphiphilic layer [152]. The most common denture material, heat-polymerized polymethyl methacrylate, exhibits a high surface roughness, hydrophobicity, and surface free energy, which contribute to the initialadhesion of microorganisms. Cyanoacrylate adhesives can change the characteristics of the resin surface, reduce the surface roughness, increase the hydrophilicity, and change the surface free energy, thus inhibiting the formation of biofilms. Adhesives also have a good biocompatibility, so they are used to coat medical devices [153]. Ultrahigh-molecular-weight polyethylene (UHMWPE) is a kind of solid, inert, and stable polymer and is the most commonly used polymer in total hip and knee arthroplasty. However, its strong hydrophobic surface makes it vulnerable to bacterial adhesion and biofilm formation. Polymer hydrophilic coatings are grafted to the surface of UHMWPE by polymer coating technology, such as covalent chemical bonds, which change the surface chemistry from hydrophobic to hydrophilic and prevent bacterial adhesion and biofilm formation [154]. Many studies on the prevention of biofilm formation have been carried out by changing the surface properties of materials, such as the roughness, hydrophobicity/hydrophilicity, surface free energy, and electric charge, to find more suitable materials that can be implanted into the human body and function favorably. For example, modification of the surface of orthopedic implants, in addition to effective resistance to bacterial adhesion, the functional retention of raw material implants, biocompatibility, the ability to resist tribological corrosion of coatings, and nontoxicity to host cells, should also be considered and evaluated [155]. _S. aureus_ is one of the most important pathogens associated with medical device biofilms and poses a major medical challenge due to its high incidence and drug resistance. The virulence factor surface proteins of _S. aureus_ can specifically bind to host extracellular matrix proteins, such as fibrinogen, fibronectin, and collagen. These proteins have been shown to have a high affinity for implants and become easily attached to the implant surface. Therefore, these proteins mediate the attachment of _S. aureus_ to the surface of the implant [156]. Targeting these mediator proteins to degrade or inhibit their production or reduce their adsorption capacity may provide a viable option for preventing _S. aureus_ biofilm formation on implant surfaces. Fibrolytic coatings (e.g., with tissue plasminogen activator (tPA)) reduce _S. aureus_ biofilm formation on indwelling medical devices both in vitro and in vivo. The tPA coating prevents the early attachment of bacteria and the subsequent accumulation of biomass by splitting local fibrin. In addition, the tPA coating increases the sensitivity of biofilm infections to antibiotics [157]. Monomeric trimethylsilane and oxygen plasma coatings cause chemical changes on the surface of the material, resulting in changes in the adsorption of intermediate proteins on the coating surface, which can reduce the adhesion of bacteria to the surface, thereby inhibiting the formation of and infection caused by biofilms [158]. It has recently been demonstrated that device-related infections caused by _S. aureus_ biofilms rely on the coagulation pathway to activate prothrombin and fibrin production. Direct thrombin inhibitors can be used to coat biomaterial surfaces to prevent staphylococcal binding and subsequent device-related infections [159].