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Colloid and Polymer Science

, Volume 274, Issue 1, pp 27–33 | Cite as

pH dependence of the kinetics of interfacial tension changes during protein adsorption from sessile droplets on FEP-Teflon

  • W. Van der Vegt
  • H. C. Van der Mei
  • H. J. Busscher
  • W. Norde
Original Contribution

Abstract

Interfacial tension changes during protein adsorption at both the solid-liquid and the liquid-vapor interface were measured simultaneously by ADSA-P from sessile droplets of protein solutions on fluoroethylenepropylene-Teflon. Four globular proteins of similar size, viz. lysozyme, ribonuclease, α-lactalbumin and Ca2+-free α-lactalbumin, and one larger protein, serum albumin, were adsorbed from phosphate solutions at varying pH values (pH 3-12). The kinetics of the interfacial tension changes were described using a model accounting for diffusion-controlled adsorption of protein molecules and conformational changes of already adsorbed molecules. The contribution of conformational changes to the equilibrium interfacial pressure was shown to be relatively small and constant with respect to pH when compared to the contribution of adsorption of the protein molecules. The model also yields the diffusion relaxation time and the rate constant for the conformational changes at the interface. Around the isoelectric point of a protein the calculated diffusion relaxation time was minimal, which is ascribed to the absence of an energy barrier to adsorption. Energy barriers to adsorption become larger at pH values away from the isoelectric point and can therefore become rate-limiting for the adsorption process. The rate constants for conformational changes at the liquid-vapor interface were maximal around the isoelectric point of a protein, suggesting a smaller structural stability of the adsorbed protein. At the solid-liquid interface the rate constants were smaller and independent of pH. indicating that conformational changes more readily occur at the liquid-vapor than at the solid-liquid interface.

Key words

Protein adsorption interfacial tension solid-liquid interface liquid-vapor interface 

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References

  1. 1.
    Baier RE, Meyer AE (1991) In: Lee LH (ed) Fundamentals of Adhesion. Plenum Press, New York, pp 407–427Google Scholar
  2. 2.
    Andrade JD (1985) In: Andrade JD (ed) Surface and Interfacial Aspects of Biomedical Polymers 2, Protein adsorption. Plenum Press, New York, pp 1–80Google Scholar
  3. 3.
    Ward AFH, Tordai L (1946) J Phys Chem 14:453–461Google Scholar
  4. 4.
    Weaver RR, Pitt WG (1992) Biomaterials 13:577–584Google Scholar
  5. 5.
    Ward AFH, Tordai L (1952) Receuil 71:572–584Google Scholar
  6. 6.
    Tornberg E (1987) J Colloid Interface Sci 64:391–402Google Scholar
  7. 7.
    Waniska RD, Kinsella JE (1985) J Agric Food Chem 33:1143–1148Google Scholar
  8. 8.
    Damodaran S, Song KB (1988) Biochim Biophys Acta 954:253–264Google Scholar
  9. 9.
    Paulsson M, Dejmek P (1992) J Colloid Interface Sci 150:394–403Google Scholar
  10. 10.
    Graham DE, Phillips MC (1979) J Colloid Interface Sci 70:403–414Google Scholar
  11. 11.
    Suttiprasit P, Krisdhashima V, McGuire J (1992) J Colloid Interface Sci 154: 316–326Google Scholar
  12. 12.
    Serrien G, Joos P (1990) J Colloid Interface Sci 139:149–159Google Scholar
  13. 13.
    Serrien G, Geeraerts G, Ghosh L, Joos P (1992) Colloids Surfaces 68: 219–233Google Scholar
  14. 14.
    Van der Vegt W, Norde W, Van der Mei HC, Busscher HJ (1995) J Colloid Interface Sci, submittedGoogle Scholar
  15. 15.
    Sarkar D, Chattoraj DK (1994) Colloids Surfaces B 2:411–417Google Scholar
  16. 16.
    Galisteo F, Norde W 91995) J Colloid Interface Sci, in pressGoogle Scholar
  17. 17.
    Graham DE, Phillips MC (1979) J Colloid Interface Sci 70:427–439Google Scholar
  18. 18.
    Jeon JS, Raghavan S, Sperline RP (1994) Colloids Surfaces A 92:255–265Google Scholar
  19. 19.
    Rotenberg Y, Boruvka L, Neumann AW (1983) J Colloid Interface Sci 93: 169–183Google Scholar
  20. 20.
    Cheng P, Li D, Boruvka L, Neumann AW (1990) Colloids Surfaces 43:151–167Google Scholar
  21. 21.
    Van der Vegt W, Van der Mei HC, Busscher HJ (1993) J Colloid Interface Sci 156:129–136Google Scholar
  22. 22.
    Miller R, Treppo S, Voigt A, Zingg W, Neumann AW (1993) Colloids Surfaces 69:203–208Google Scholar
  23. 23.
    Van der Vegt W, Van de Mei HC, Busscher HJ (1993) Langmuir 10:1314–1318Google Scholar
  24. 24.
    Kondo A, Oku S, Higashitani K (1991) J Colloid Interface Sci 143:214–221Google Scholar

Copyright information

© Steinkopff Verlag 1996

Authors and Affiliations

  • W. Van der Vegt
    • 1
  • H. C. Van der Mei
    • 1
  • H. J. Busscher
    • 1
  • W. Norde
    • 2
  1. 1.Laboratory for Materia TechnicaUniversity of GroningenGroningenThe Netherlands
  2. 2.Department of Physical and Colloid ChemistryAgricultural University of WageningenWageningenThe Netherlands

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