Background: Implant-associated infections are a result of bacterial adhesion to an implant surface
and subsequent biofilm formation at the implantation site. This study compares different magnesium
materials based on their ability to resist bacterial adhesion as well as further biofilm formation.
Material and Methods: The surfaces of four magnesium-based materials (Mg2Ag, Mg10Gd,
WE43 and 99.99% pure Mg) were characterized using atomic force microscope. In addition, the
samples were tested for their ability to resist biofilm formation. Planktonic bacteria of either S.
epidermidis or E. faecalis were allowed to adhere to the magnesium surfaces for two hour followed
by rinsing and, for S. epidermidis, further incubation of 24, 72 and 168 h was carried out. Results: E.
faecalis had a significantly stronger adhesion to all magnesium surfaces compared to S. epidermidis
(p = 0.001). Biofilm growth of S. epidermidis was different on various magnesium materials: the
amount of bacteria increased up to 72 h but interestingly a significant decrease was seen at 168 h
on Mg2Ag and WE43 surfaces. For pure Mg and Mg10Gd the biofilm formation reached plateau at
72 h. Surface characteristics of resorbable magnesium materials were changing over time, and the
surface was generally less rough at 168 h compared to earlier time points. No correlation was
found between the surface topology and the amount of adherent bacteria. Conclusion: In early
stages of biofilm adhesion, no differences between magnesium materials were observed. However,
after 72 h Mg2Ag and WE43 had the best ability to suppress S. epidermidis’ biofilm formation. Also,
bacterial adhesion to magnesium materials was not dependent on samples’ surface topology.