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Normal and Friction Forces between Mucin and Mucin-Chitosan Layers in Absence and Presence of SDS
KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.ORCID-id: 0000-0002-5444-7276
KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.ORCID-id: 0000-0002-2288-819X
2008 (Engelska)Ingår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 324, nr 1-2, s. 246-256Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Employing the colloidal probe AFM technique we have investigated normal and friction forces between flat mica surfaces and silica particles coated with mucin and combined mucin-chitosan layers in presence and absence of anionic surfactant, SDS, in 30 mM NaCl solution. We have shown that the normal interactions between mucin coated mica and silica surfaces are dominated by long-range steric repulsion on both compression and decompression. Friction forces between such mucin layers are characterized by a low effective friction coefficient, mu(eff) = 0.03 +/- 0.02, which is lower than the value of 0.13 +/- 0.02 observed when chitosan layers were adsorbed. Forces between combined mucin-chitosan layers have Adsorption of chitosan on mucin results in considerable compaction of the layer, also been measured. and development of attractive forces detectable on separation. Friction between mucin-chitosan layers in 30 mM NaCl solution is high, with mu(eff) approximate to 0.4. Adsorption of additional mucin to this layer results in no improvement with respect to lubrication as compared to the mucin-chitosan layer, and mu(eff) approximate to 0.4 is We argue that the layers containing both mucin and chitosan are not strictly layered but rather observed. As a result attractive interactions between oppositely charged moieties of sialic acid strongly entangled. residues from mucin and amine groups from chitosan residing on the opposing surfaces contribute to the increased friction. The effects of SDS on normal and friction forces between combined mucin-chitosan layers were also investigated. The relation between surface interactions and friction properties is discussed.

Ort, förlag, år, upplaga, sidor
2008. Vol. 324, nr 1-2, s. 246-256
Nyckelord [en]
mucin, chitosan, SDS, friction force, AFM, lubrication, steric force, adhesion
Nationell ämneskategori
Fysikalisk kemi
Identifikatorer
URN: urn:nbn:se:kth:diva-8078DOI: 10.1016/j.jcis.2008.04.055ISI: 000257232100037Scopus ID: 2-s2.0-49949152619OAI: oai:DiVA.org:kth-8078DiVA, id: diva2:13304
Anmärkning
QC 20100903. Uppdaterad från submitted till published (20100903).Tillgänglig från: 2008-03-07 Skapad: 2008-03-07 Senast uppdaterad: 2017-12-14Bibliografiskt granskad
Ingår i avhandling
1. Lubrication and Surface Properties of Adsorbed Layers of Polyelectrolytes and Proteins
Öppna denna publikation i ny flik eller fönster >>Lubrication and Surface Properties of Adsorbed Layers of Polyelectrolytes and Proteins
2008 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Friction forces between protein / polyelectrolyte layers, adsorption properties of proteins, and conformational changes due to variation in electrolyte concentration have been investigated. The aim was to obtain better understanding of adsorbed layer properties, with focus on the relation between layer structure and lubrication capabilities. The major techniques used were AFM (atomic force microscope) with colloidal probe for normal force and friction measurements together with QCM-D (quartz crystal microbalance with dissipation) for measurement of adsorption and conformational changes of adsorbed layers.

A comparison between some techniques for calibration of the AFM instrument for friction measurements was made to find the most suitably one for colloidal probe friction measurements in aqueous solutions. It is suggested that the normal and torsional Sader methods are preferred in combination with torsional detector sensitivity measurement, for which one new methodology has been proposed.

Adsorption was studied for bovine serum albumin, cytochrome c, myoglobin and mucin, whereas conformational changes of the adsorbed layer were monitored only for mucin. It was found that it was essential to take into account bulk density and viscosity changes for correct interpretations of QCM data when studying the effect of changes in electrolyte type and concentration on preadsorbed layers of mucin, and also when having different (high) concentrations of proteins in the measuring solution. The adsorbed amount of proteins appears to depend on the strength of the surface attachment, in such a manner that a too high affinity reduces the adsorbed amount.

Friction properties in aqueous solution have been studied for adsorbed layers of PEO45MEMA:METAC co-polyelectrolytes, with varying density of grafted PEO45 side chains and varying charge density, as well as for a naturally occurring polyelectrolyte (chitosan) and the glycoprotein mucin. These polymers were used to cover a wide range of different types of adsorbed layers and interactions to gain a better understanding of friction mechanisms and demands on layer properties for achieving favourable lubrication. It was found that the common features of low friction layers are that no attractive forces are present, and that excluded volume and / or electrostatic forces counteract chain interpenetration under load.

Ort, förlag, år, upplaga, sidor
Stockholm: KTH, 2008. s. vii, 59
Serie
Trita-CHE-Report, ISSN 1654-1081 ; 2008:16
Nyckelord
biochemistry, biomedical engineering
Nationell ämneskategori
Fysikalisk kemi
Identifikatorer
urn:nbn:se:kth:diva-4663 (URN)978-91-7178-891-7 (ISBN)
Disputation
2008-03-27, Sal F3, KTH, Lindstedtsvägen 26, Stockholm, 10:00
Opponent
Handledare
Anmärkning
QC 20100903Tillgänglig från: 2008-03-07 Skapad: 2008-03-07 Senast uppdaterad: 2010-09-03Bibliografiskt granskad

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