Biomedical Engineering Reference
In-Depth Information
the laboratory (Chandra et al., 2001) and the ability to investigate
in vivo
biofilm growth or
drug susceptibility. Different studies have already described such models, mainly
addressing procedures that are able to limit yeast adherence and biofilm formation. Some of
these technologies were originally proposed as artificial dental plaque biofilm model
systems (reviewed by Sissons, 1997), especially for plaque biology studies in caries and
periodontitis research. This section will report on the experimental models producing
Candida
biofilms onto biomaterials. Table 1 summarizes some contributions from literature.
design
reference
material
in vitro
models
static culture models
- material dived in solution
Chandra et al., 2001
acrylic, silicone
- poloxamer gel in Petri dish
Percival et al., 2007
material covered by gel
- 96-well culture microtiter plate
Peeters et al., 2008
polystyrene
- titanium powder
Ahariz & Courtois, 2010
titanium powder
continuous culture models
- continuous flow culture system
Uppuluri et al., 2009
silicon elastomer
- Modified Robbins Device
Coenye et al., 2008
- constant depth film fermenter
Lamfon et al., 2003
enamel, dentine, acrylic
in vivo
models
central venous catheter
acrylic denture
subcutaneous catheter
- human models Budtz-Jörgensen et al., 1981 tape or acrylic disk
Table 1. Experimental designs reported in the literature to produce
Candida
-biofilms.
Andes et al., 2004
Nett et al., 2010
Ricicová et al., 2010
- animal models
Candida albicans
can be grown with or without the addition of saliva on different materials
used in dentistry including acrylic resins, denture-lining material, porcelain, composite,
amalgam, hydroxyapatite, silicone, and polystyrene.
3.1
In vitro
models
In vitro
models consist of static cultures or continuous cultures.
3.1.1 Static culture models
Mono-species biofilms can be experimentally grown on pieces of materials currently used in
dentistry, such as polymethylmethacrylate strips or silicone elastomer disks (Chandra et al.,
2001). Some surfaces prepared from mucosa (epithelial cell cultures) or hard tooth tissues
(enamel, dentine) were used as well. The materials are immersed in assay tubes or in multi-
well culture plates containing a contaminated solution similar to saliva for a predefined
incubation period. The polystyrene wall of the container itself has been used as an adherent
surface for biofilm formation: 96-well plates allow management of experiments with
numerous replications in various conditions (Peeters et al., 2008). Specific studies of the
adhesion phase require an intermediate washing step to remove non-adherent yeast cells.
Evaluation of the biofilm growth phase is generally based on microbial cell staining (crystal
violet, among others), metabolic activities (tetrazolium test), biomass determination (dry
weight, incorporation of radioactive tracer such as amino acids), or microscopic
examination.
