β-lactoglobulin (β-Lg), bovine serum albumin (BSA), α-lactalbumin
(α-Lac), and β-casein were adsorbed onto
silanized silica surfaces of low and high hydrophobicity
for 8 h, and β-Lg and BSA for 1 h. The surfaces were
incubated in buffer for 0, 5, 10, or 15 h and then contacted
with Listeria monocytogenes for 3 h. Cell adhesion was
quantified using image analysis. Following 8 h of protein
contact, adhesion to both surfaces was greatest when β-Lg
was present and lowest when BSA was present. Preadsorption
of α-Lac and β-casein showed an intermediate effect on cell
adhesion. Adsorption of β-Lg for 1 h resulted in lower
numbers of cells adhered as compared to the 8 h adsorption
time, while the opposite was observed with BSA, but adhesion
to BSA was observed to decrease slowly with film age to
values comparable to the 8 h tests.
The adsorption of BSA and β-Lg to both surfaces was
also carried out where each protein was allowed to contact
the surface in sequence and simultaneously. In sequential
tests performed with an 8 h contact/protein, cell numbers on
each surface were near that expected for the bare
hydrophobic surface when β-Lg contact preceded introduction
of BSA, whereas adhesion was reduced to values below that
expected for the bare hydrophilic surface when BSA preceded
β-Lg contact. In short-term sequential tests (1 h
contact/protein), adhesion was lower than that recorded on
bare hydrophilic surfaces in each case. Adhesion to each
surface following contact with an equimolar mixture of β-Lg
and BSA was lower than that measured on the bare hydrophilic
surface in each case, with adhesion following 1 h contact
being greater than that following 8 h contact. Adhesion
following competitive adsorption was greater to hydrophobic
than to hydrophilic surfaces. These results were explained
with reference to the surface passivating character of BSA,
and its ability to rapidly attain a nonexchangeable state
upon adsorption, relative to β-Lg. / Graduation date: 1995
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27432 |
| Date | 01 August 1994 |
| Creators | Al-Makhlafi, Hamood K. |
| Contributors | McGuire, Joseph, Daeschel, Mark A. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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