(745a) Controlling Microbial Adhesion and Biofilm Formation by Self-Assembled Monolayers of Alkanethiols Presenting Mannitol Group

Biofilms are sessile colonies of
microbes attached to a variety of surfaces. Such ubiquitous structures cause serious problems such as persistent infections and
biocorrosion. According to NIH, biofilms are involved in approximately 80% of
human bacterial infections. We recently reported that self-assembled monolayers
presenting tri(ethylene) glycol (TEG) are highly resistant to adhesion and
biofilm formation of Escherichia coli. To further understand
microbe-surface interactions and to develop effective biofilm control
strategies, novel self-assembled monolayers (SAMs) of alkanethiols presenting
mannitol group on gold films were analyzed for their resistance to biofilm
formation in this study. The cell adhesion and biofilm formation were monitored
with confocal laser scanning microscopy. The three dimensional structure of
biofilms was analyzed with the COMSTAT software to quantify the biomass,
surface coverage, and thickness. The mannitol-terminated SAM exhibited strong
resistance not only to the biofilm formation of E. coli RP437 (84.1% ± 4.5%
reduction), but also to that of the opportunistic human pathogens Pseudomonas
aeruginosa PA01 (88.8% ± 9.0% reduction) and Candida albicans SC5314
(86.6% ± 9.0% reduction) compared to bare gold surface. This suggests that the
bioinertness of mannitol-terminated SAMs is not species-specific because they
are resistant to both bacterial and fungal biofilm formation. In addition, the long-term
biofilm assay in a flow cell showed that mannitol-terminated SAMs were resistant
to E. coli biofilm formation for at least 4 weeks, which is four times
longer than TEG-terminated SAMs. To our best knowledge, mannitol-terminated SAM
has the longest resistance to microbial biofilm formation compared to other
SAMs reported to date. Such well-defined surfaces are an ideal platform for
studying microbes-surface interactions and developing effective control
strategies for antifouling and anticorrosion applications.

Keyword: self-assembled
monolayers, biofilm, mannitol, tri-(ethylene glycol)