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Properties of Interfacial Proteinaceous Films with Emphasis on Oral Systems

Hahn Berg, Cecilia LU (2003)
Abstract
The present thesis addresses three issues related to proteinaceous films at solid/liquid interfaces: adsorption, lubrication and enzymatic interactions. Most of the work has been devoted to oral systems. In addition, gelatin has been investigated as a model protein.



Salivary protein adsorption from human whole saliva (HWS) onto hydroxyapatite (HA) and silica has been characterised using ellipsometry. The shapes of the adsorption isotherms at HA and silica were similar, indicating similar surface affinities for the two substrates. Desorption, as induced by the addition of sodium dodecyl sulphate (SDS) to the salivary pellicles, was found to occur in the same SDS concentration range at both surfaces, although a residual... (More)
The present thesis addresses three issues related to proteinaceous films at solid/liquid interfaces: adsorption, lubrication and enzymatic interactions. Most of the work has been devoted to oral systems. In addition, gelatin has been investigated as a model protein.



Salivary protein adsorption from human whole saliva (HWS) onto hydroxyapatite (HA) and silica has been characterised using ellipsometry. The shapes of the adsorption isotherms at HA and silica were similar, indicating similar surface affinities for the two substrates. Desorption, as induced by the addition of sodium dodecyl sulphate (SDS) to the salivary pellicles, was found to occur in the same SDS concentration range at both surfaces, although a residual layer was observed at HA.



Normal and lateral forces between surfaces bearing adsorbed salivary films have been investigated by colloidal probe atomic force microscopy. The presence of salivary pellicles, adsorbed from HWS, largely reduced the friction between hard surfaces. The normal forces acting between such salivary films were found to be purely repulsive. Further investigation of three pellicle key proteins (human acidic proline-rich protein 1 (PRP-1), human statherin and mucin (bovine submaxillary mucin, BSM)) revealed lubricating capacities in the order PRP-1 > BSM > statherin.



Investigations of enzymatic degradation of proteinaceous films of oral origin indicated that the observed removal of dental plaque by krillase may partly be due to a degradation of the salivary pellicle. The results obtained demonstrate the potential of krillase for plaque control.



Interactions upon exposure of adsorbed gelatin layers to the proteolytic enzymes trypsin and krillase have been studied using ellipsometry and total internal reflectance fluorescence spectroscopy. In brief, the behaviour at hydrophobic substrates was to a large extent determined by proteolytic degradation, although interfacial exchange processes could not be disregarded. At hydrophilic substrates, the balance between interfacial degradation and exchange was reversed. Furthermore, temperature effects were noted on the enzyme-induced desorption rates and the residual adsorbed amounts. (Less)
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author
opponent
  • Dr Thomas, Robert K., Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, UK
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Food and drink technology, Livsmedelsteknik, trypsin, SDS elutability, statherin, salivary proteins, salivary pellicle, proline-rich proteins, plaque control, mucins, microbial adhesion, lubrication, krillase, intraoral friction, hydroxyapatite, gelatin, exchange, enzymes, ellipsometry, dental plaque, degradation, colloidal probe, calcium-induced precipitation, adsorption, atomic force microscopy, total internal reflectance fluorescence spectroscopy
pages
64 pages
publisher
Food Technology, Lund University
defense location
Lecture hall B, Center for Chemistry and Chemical Engineering, Lund Institute of Technology, Lund, Sweden
defense date
2003-12-05 10:30
ISBN
91-628-5754-1
language
English
LU publication?
yes
id
cb507f56-78bd-4166-adce-877e485d5923 (old id 466479)
date added to LUP
2007-10-14 13:49:16
date last changed
2016-09-19 08:45:12
@phdthesis{cb507f56-78bd-4166-adce-877e485d5923,
  abstract     = {The present thesis addresses three issues related to proteinaceous films at solid/liquid interfaces: adsorption, lubrication and enzymatic interactions. Most of the work has been devoted to oral systems. In addition, gelatin has been investigated as a model protein.<br/><br>
<br/><br>
Salivary protein adsorption from human whole saliva (HWS) onto hydroxyapatite (HA) and silica has been characterised using ellipsometry. The shapes of the adsorption isotherms at HA and silica were similar, indicating similar surface affinities for the two substrates. Desorption, as induced by the addition of sodium dodecyl sulphate (SDS) to the salivary pellicles, was found to occur in the same SDS concentration range at both surfaces, although a residual layer was observed at HA.<br/><br>
<br/><br>
Normal and lateral forces between surfaces bearing adsorbed salivary films have been investigated by colloidal probe atomic force microscopy. The presence of salivary pellicles, adsorbed from HWS, largely reduced the friction between hard surfaces. The normal forces acting between such salivary films were found to be purely repulsive. Further investigation of three pellicle key proteins (human acidic proline-rich protein 1 (PRP-1), human statherin and mucin (bovine submaxillary mucin, BSM)) revealed lubricating capacities in the order PRP-1 &gt; BSM &gt; statherin.<br/><br>
<br/><br>
Investigations of enzymatic degradation of proteinaceous films of oral origin indicated that the observed removal of dental plaque by krillase may partly be due to a degradation of the salivary pellicle. The results obtained demonstrate the potential of krillase for plaque control.<br/><br>
<br/><br>
Interactions upon exposure of adsorbed gelatin layers to the proteolytic enzymes trypsin and krillase have been studied using ellipsometry and total internal reflectance fluorescence spectroscopy. In brief, the behaviour at hydrophobic substrates was to a large extent determined by proteolytic degradation, although interfacial exchange processes could not be disregarded. At hydrophilic substrates, the balance between interfacial degradation and exchange was reversed. Furthermore, temperature effects were noted on the enzyme-induced desorption rates and the residual adsorbed amounts.},
  author       = {Hahn Berg, Cecilia},
  isbn         = {91-628-5754-1},
  keyword      = {Food and drink technology,Livsmedelsteknik,trypsin,SDS elutability,statherin,salivary proteins,salivary pellicle,proline-rich proteins,plaque control,mucins,microbial adhesion,lubrication,krillase,intraoral friction,hydroxyapatite,gelatin,exchange,enzymes,ellipsometry,dental plaque,degradation,colloidal probe,calcium-induced precipitation,adsorption,atomic force microscopy,total internal reflectance fluorescence spectroscopy},
  language     = {eng},
  pages        = {64},
  publisher    = {Food Technology, Lund University},
  school       = {Lund University},
  title        = {Properties of Interfacial Proteinaceous Films with Emphasis on Oral Systems},
  year         = {2003},
}