The lubricating properties of human whole saliva

Bongaerts, J. H. H., Rossetti, D. and Stokes, J. R. (2007) The lubricating properties of human whole saliva. Tribology Letters, 27 3: 277-287. doi:10.1007/s11249-007-9232-y


Author Bongaerts, J. H. H.
Rossetti, D.
Stokes, J. R.
Title The lubricating properties of human whole saliva
Journal name Tribology Letters   Check publisher's open access policy
ISSN 1023-8883
Publication date 2007-09
Sub-type Article (original research)
DOI 10.1007/s11249-007-9232-y
Volume 27
Issue 3
Start page 277
End page 287
Total pages 11
Place of publication Bussum, Netherlands
Publisher Baltzer Science Publishers
Language eng
Subject 09 Engineering
Abstract We demonstrate the efficient boundary lubricating properties of human whole saliva (HWS) in a soft hydrophobic rubbing contact, consisting of a poly(dimethylsiloxane) (PDMS) ball and a PDMS disk. The influence of applied load, entrainment speed and surface roughness was investigated for mechanically stimulated HWS. Lubrication by HWS results in a boundary friction coefficient of mu approximate to 0.02, two orders of magnitude lower than that obtained for water. Dried saliva on the other hand results in mu approximate to 2-3, illustrating the importance of hydration for efficient salivary lubrication. Increasing the surface roughness increases the friction coefficient for HWS, while it decreases that for water. The boundary lubricating properties of HWS are less sensitive to saliva treatment than are its bulk viscoelastic properties. Centrifugation and ageing of HWS almost completely removes the shear thinning and elastic nature observed for fresh HWS. In contrast, the boundary friction coefficients are hardly affected, which indicates that the high-M (w) (supra-)molecular structures in saliva, which are expected to be responsible for its rheology, are not responsible for its boundary lubricating properties. The saliva-coated PDMS surfaces form an ideal model system for ex-vivo investigations into oral lubrication and how the lubricating properties of saliva are influenced by other components like food, beverages, oral care products and pharmaceuticals.
Keyword Saliva
Soft-tribology
Biolubrication
Oral lubrication
Biomimetic surfaces
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Chemical Engineering Publications
 
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Created: Wed, 01 Jul 2009, 16:03:53 EST