Ellipsometry was used to study the effects of surface energetics
and temperature on the equilibrium adsorptive behavior exhibited by
β-lactoglobulin. β-Lactoglobulin isotherms at 25, 37, and 55°C were
constructed for this purpose. The surfaces of acrylic, polycarbonate,
polyester, glass, and #304 stainless steel were contacted with protein
solutions of varying concentration, buffered at pH 6.7 with mono- and
dibasic sodium phosphate. After three hours, the surfaces were mildly
rinsed with deionized water and dried overnight. Optical properties of
each film were ellipsometrically measured and the adsorbed mass was
calculated as a function of film thickness and refractive index.
Contact angle methods were used to measure the hydrophobicity
exhibited by each of the five solid surfaces. However, interpretation
of protein adsorption results based solely on solid surface
hydrophobicity proved unworkable. For polymers (low-energy surfaces),
the adsorbed mass of protein was explained with reference to the degree
of extensibility of molecular structure. Glass (a high-energy surface)
was observed to adsorb the greatest mass of β-lactoglobulin. Stainless
steel was observed to adsorb the least mass of β-lactoglobulin and the
plateau values of protein adsorption were found to be consistent with
those reported elsewhere, and to lie within the range of adsorbed mass
on metal surfaces in general.
The temperature dependence of β-lactoglobulin adsorption could not
be clearly quantified. Apparently, any differences in adsorbed mass
were too small to be detected by the instrument. In any event, other
investigators have not detected any significant difference in adsorbed
mass as long as the temperature was below the denaturation temperature
of the protein. / Graduation date: 1991
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/38126 |
| Date | 07 February 1991 |
| Creators | Al-Malah, Kamal Issa Masoud |
| Contributors | McGuire, Joseph, Sproull, Robert D. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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