Coatings and surface modifications imparting antimicrobial activity to orthopedic implants

Abstract

Bacterial colonization and biofilm formation on an orthopedic implant surface is one of the worst possible outcomes of orthopedic intervention in terms of both patient prognosis and healthcare costs. Making the problem even more vexing is the fact that infections are often caused by events beyond the control of the operating surgeon and may manifest weeks to months after the initial surgery. Herein, we review the costs and consequences of implant infection as well as the methods of prevention and management. In particular, we focus on coatings and other forms of implant surface modification in a manner that imparts some antimicrobial benefit to the implant device. Such coatings can be classified generally based on their mode of action: surface adhesion prevention, bactericidal, antimicrobial-eluting, osseointegration promotion, and combinations of the above. Despite several advances in the efficacy of these antimicrobial methods, a remaining major challenge is ensuring retention of the antimicrobial activity over a period of months to years postoperation, an issue that has so far been inadequately addressed. Finally, we provide an overview of additional figures of merit that will determine whether a given antimicrobial surface modification warrants adoption for clinical use.

Atomic layer deposition of nano-TiO_2 thin films with enhanced biocompatibility and antimicrobial activity for orthopedic implants

“…9 It is clear that both chemical and physical properties of the surface play a major role in modulating the biological events directly at the tissue-implant interface. [10][11][12] For Ti-based implants, the naturally formed TiO 2 thin layers are thought to act as a barrier between the implant and tissue to prevent metallic ion release into the body and consequently minimizing the chances of an immune response; however, recent studies have indicated that this few-nanometerthin layer does not provide sufficient long-term corrosion protection. 2,13 Understanding the role of this native TiO 2 film on biomedical Ti implants paves the way for in-depth studies focused on developing a multifunctional Ti implant surface by modifying and structuring the natural oxide layer to further improve biocompatibility.…”

Review: the potential impact of surface crystalline states of titanium for biomedical applications

“…The biofilm renders the bacterial colony resistant to antibiotics and immune cells (Kargupta et al, 2014). Bacterial infections can lead to the failure of orthopedic and dental implants due to bone resorption (Ramalingam et al, 2012, Gao et al, 2011.…”

Biocompatibility and Anti-Microbiological Activity Characterization of Novel Coatings for Dental Implants: A Primer for Non-Biologists

“…Focal adhesions are crucial for the spreading and flattening of a cell that is important to gain strong adhesion. Together with growth Kargupta et al (2014) and Rimondini et al (1997) Toxic to adherent bacteria: photoactive coatings, metal-impregnated, antimicrobial peptides, quaternary ammonium salts Adherent bacteria will be killed, infections prevention Campoccia et al (2013), Hasan et al (2013), and Kargupta et al (2014) Controlled, time-release of antibiotics Adherent bacteria will be killed, infections prevention Actis et al, 2013;Hasan et al (2013), and Kargupta et al (2014) integrin receptor-matrix ligand occurs within minutes after the initial surface recognition. Adhesion with proper cell spreading then takes several hours during which the cell-implant contact area increases 100-fold (Cohen et al, 2004).…”

“…A biofilm is a thin but robust layer of microorganisms, such as bacteria, fungi, and yeast that adhere to the implant surface similar to the dental plaque sticking to the teeth (Actis et al, 2013;Kargupta et al, 2014). These microorganisms can cause serious infections around the implant initiating progressive bone loss leading to loosening or even loss of the implant (Wood et al, 2004).…”

“…Because of this interaction, antibacterial activity tests should also be considered when testing the biocompatibility of a novel coating. Modern antimicrobial coatings are designed to prevent biofilm formation by, e.g., preventing bacterial adhesion, killing bacteria, or by accelerating osteoblast adhesion (reviewed in Hasan et al, 2013;Kargupta et al, 2014).…”