To determine whether the presence of matrix material indeed increases the resistance of biofilms to antifungal products, Al-Fattani and Douglas (2006) grew C. albicans biofilms under static conditions, resulting in a small amount of matrix material, and under conditions of continuous flow using a modified Robbins device (MRD).
Fan and coworkers proposed the incorporation of epidermal growth factor (EGF) into a synthetic polymer matrix material to increase cell survival under such conditions [ 4].
They found that surface-exposed EGF promoted cell attachment to the matrix material and increased MSC spreading and survival when compared with media containing solubilized EGF.
The appearance of red or pink colonies on the Congo red plates indicated that Congo red had bound the extracellular matrix material; an increasing depth of color indicated high production levels of the cellulose/curli matrix.
The results indicate that, with sliding grain boundaries, the stress enhancement factor for the composites is much higher than the one observed for the matrix material and its value increases with increasing reinforcement aspect ratio, reduction in the matrix grain size and sliding interfacial behavior between the reinforcement and the matrix.
Recently, it was discovered that extracellular DNA (eDNA) is also an important component of biofilm matrix material, with amounts increasing over time, and that treatment with deoxyribonuclease I (DNAse) decreases biofilm biomass at later time points (Martins et al. 2010).
The introduced model predicts that due to adding 30V/V% fibers to the matrix material, the effective isotropic viscosity increases to 1.7-fold of the matrix viscosity (blue circle).
The critical stress intensity factor obtainable by optimizing the reinforcement size and morphology in the composite body is hardly higher than a few times that of the matrix material, an order-of-magnitude increase requiring a mismatch in the inherent elastic and/or fracture properties of matrix and reinforcement which is not easily achievable among known ceramics.
Asc10 is not readily visualized with this type of SEM imaging unless immunogold labeling is used [24], so the extracellular material observed is not likely Asc10 itself, but matrix material whose synthesis may be increased by Asc10-mediated enhancement of biofilm formation.
