Biomedical subjects

T Arnebrant

Publications and source records attributed to T Arnebrant.

24 records · Page 2Linked to original sources

PubMed1992

In vitro interactions of anionic and cationic surfactants with salivary fractions on well-defined solid surfaces.

Ellipsometry was used to study the interaction of one anionic (SDS) and one cationic (CTAB) surfactant with films adsorbed from six different salivary fractions obtained after fractionation of whole unstimulated saliva on a Superdex 200 Hiload gel filtration column. Experiments were performed on both hydrophilic silica and hydrophobic methylated silica surfaces. The results of this study indicate that the adhesive and cohesive properties of the films adsorbed from the individual fractions were strongly dependent on the surface characteristics of the substrates and that the outcome of protein/surfactant interactions was dependent on factors such as protein composition, surfactant charge, and substrate characteristics. These interactions probably involve replacement of the adsorbed proteins by surfactants or protein/surfactant complex formation. The anionic surfactant seemed to be more efficient in removing adsorbed salivary proteins than the cationic one.

Adhesiveness↗

PubMed1992

Initial studies on the behavior of salivary proteins at liquid/air interfaces.

The mode of adsorption of salivary proteins at air/liquid interfaces was studied by using the drop volume technique to measure the kinetics of surface tension decay of aqueous salivary solutions. Adsorption of salivary proteins from whole saliva was fast, with a plateau value of the surface tension of 43 (+/- 2) mNm-1. As the concentration of saliva was reduced, the plateau value of surface tension increased and was achieved more slowly. The reduction in surface tension of aqueous solutions was larger for salivary proteins than for many other proteins reported.

Adsorption↗

PubMed1991

Protein adsorption to solid surfaces.

The phenomenon of protein adsorption to solid surfaces affects the performance of many materials and processes, in areas ranging from medicine to biochemical engineering. Controlling protein adsorption, from solutions of single proteins as well as from more complex mixtures, requires an understanding of the mechanism(s) by which it occurs. This, in turn, entails detailed characterization of both the protein and the solid surface and identification of those factors controlling the adsorption process.

Adsorption↗

PubMed1991

Effect of whole saliva on the rheologic behavior of extracellular water-soluble glucan produced by Streptococcus mutans.

The viscosity of mixtures of Streptococcus mutans water-soluble glucan and stimulated whole saliva or buffer was measured at pH 5, 6, 7, and 8. The viscosity was measured as a function of shear rate in the range 15 s-1-230 s-1. Though the centrifuged saliva had a viscosity close to that of water it increased the viscosity of the glucan up to 65% at pH 6 and 55% at pH 7 and at a shear rate of 20 s-1, indicating an interaction between saliva components and glucan that could be an important part of the cohesive forces of plaque matrix. The interaction between saliva and glucan was less pronounced at pH 5 and 8, which indicates a charge-dependent interaction. The viscosity increase at pH 6 and 7 was higher at low than at high shear rates, suggesting a higher contribution to plaque stability when weak as opposed to high mechanical forces are exerted on the plaque.

Buffers↗

PubMed1991

The effect of ionic surfactants on salivary proteins adsorbed on silica surfaces.

The adsorption onto silicon oxide surfaces from water and 0.1 M acetate buffer containing 10% parotid saliva at 25 degrees C and 35 degrees C and at pH 6 was monitored in situ using ellipsometry. The silicon oxide surface was used as a model for dental enamel. The adsorption kinetics and the reversibility on rinsing were determined, and the desorbable fraction was found not to change after either 30 or 120 min of adsorption. Addition of sodium dodecyl sulfate after 30 or 120 min of saliva adsorption caused strong desorption. Rinsing 30 min after surfactant addition caused some redeposition if saliva was present, whereas continued desorption occurred in the absence of saliva. Cetyltrimethylammonium bromide caused either an increase or a slight decrease in the amount adsorbed when added after 30 min and 120 min, respectively. For both times, rinsing caused desorption, left the same amount adsorbed, and was not affected by the presence or absence of saliva in solution. No major effect from temperature and ionic strength was found.

Acetates↗

PubMed1991

Influence of delmopinol on bacterial zeta-potentials and on the colloidal stability of bacterial suspensions.

Delmopinol is a low molecular weight surface-active compound that has been shown to be effective against dental plaque both in vitro and in vivo and against gingivitis in vivo. To study the mode of action of delmopinol, the influence of the compound on the stability of bacterial suspensions, both with and without saliva, and on the zeta-potentials of oral streptococci was studied. The results showed that delmopinol reduced the magnitude of the zeta-potentials, but, in contrast, the colloidal stability of the bacterial suspensions without saliva was increased. The explanation of these observations could be that non-DLVO interaction components, such as repulsive hydration/steric forces, have come into effect at very close distances between two approaching bacterial cells. To judge from the present results, it is possible that delmopinol forms films on bacterial cells in a plaque, thereby facilitating mechanical removal.

Bacterial Adhesion↗