Lecture
Biomaterials-associated infections
(BAI) are a widespread problem. Due to multi-resistant microorganisms, an
alternative and new antibiotic-free strategy to reduce the risk of a BAI is the
modification of the materials surface topography on the nanometer scale. Nanoparticles
are used for nanostructuring materials surfaces. Often only qualitative
adhesion properties are analyzed limiting the quantitative information about adhesion
forces between microbial cells and materials surfaces. An option focusing on
measuring adhesion forces is force-distance curves.
Therefore, the aims of
this study are [i] to investigate the adhesion of Candida albicans as function of materials surfaces physically
nanostructured with nanoparticles and [ii] to investigate force-distance curves
of C. albicans on these materials
surfaces.
Different gold nanoparticle
(AuNP) densities were immobilized on gold sputtered surfaces. The
nanostructured materials surfaces were characterized by atomic force microscopy
(AFM), contact angle measurements and X-ray photoelectron spectroscopy.
Microbial adhesion on these surfaces was investigated for different adhesion
times and adhesion kinetics were obtained using confocal laser scanning
microscopy. For quantitative analysis, microbial cells were attached on a
hollow AFM cantilever.
The investigated
surfaces with AuNPs densities of 25 ± 4 AuNP/µm2 and
61 ± 10 AuNP/µm2 as well as unstructured control
surfaces showed no statistically significant differences in contact angle and
surfaces chemistry. A reduced microbial adhesion was observed on the
nanostructured surfaces compared to the unstructured control surfaces. The AuNP
function as contact points for initial microbial adhesion which can be confirmed
by the results of the force-distance curves. A lower AuNP density led to a
reduced microbial adhesion as well as a reduced adhesion force between the
microbial cells and materials surfaces.
This study will provide new insight into microbial
adhesion on materials surfaces structured in the nanometer range. These
surfaces may have a potential for reducing microbial adhesion and the risk of
BAIs.
