Home / Questions / Microorganisms adhere to inert and or living surfaces in moist environments by secreting a...
Microorganisms adhere to inert and/or living surfaces in moist environments by secreting a slimy, glue-like substance known as a biofilm. A typical example of a biofilm is the plaque that forms on your teeth.
a)The hypertext book “Biofilms” (http://www.erc.montana.edu/biofilmbook) indicates that the time required for a solute to reach 90% of the bulk fluid concentration at the base of a flat slab biofilm is given by
where Deff is the effective diffusion coefficient of solute in the biofilm. On the other hand, the time required for a solute to reach 90% of the bulk fluid concentration at the center of a spherical biofilm is given by
How can one derive these equations? What does L represent in Eq. (1)?
b) Suppose that there is hemispherical dental plaque with a radius of 250μm on the surface of the tooth. How long must one rinse with mouthwash for the antimicrobial agent to penetrate to the tooth surface. Take Deff = 0.75 ×10−10 m2/s.
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