Adsorption of lysozyme on base metal surfaces in the presence of an external electric potential

Htwe Ei Ei, Yuhi Nakama, Hiroshi Tanaka, Hiroyuki Imanaka, Naoyuki Ishida, Koreyoshi Imamura

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The impact of external electric potential on the adsorption of a protein to base metal surfaces was examined. Hen egg white lysozyme (LSZ) and six types of base metal plates (stainless steel SUS316L (St), Ti, Ta, Zr, Cr, or Ni) were used as the protein and adsorption surface, respectively. LSZ was allowed to adsorb on the surface under different conditions (surface potential, pH, electrolyte type and concentration, surface material), which was monitored using an ellipsometer. LSZ adsorption was minimized in the potential range above a certain threshold and, in the surface potential range below the threshold, decreasing the surface potential increased the amount of protein adsorbed. The threshold potential for LSZ adsorption was shifted toward a positive value with increasing pH and was lower for Ta and Zr than for the others. A divalent anion salt (K2SO4) as an electrolyte exhibited the adsorption of LSZ in the positive potential range while a monovalent salt (KCl) did not. A comprehensive consideration of the obtained results suggests that two modes of interactions, namely the electric force by an external electric field and electrostatic interactions with ionized surface hydroxyl groups, act on the LSZ molecules and determine the extent of suppression of LSZ adsorption. All these findings appear to support the view that a base metal surface can be controlled for the affinity to a protein by manipulating the surface electric potential as has been reported on some electrode materials.

Original languageEnglish
Pages (from-to)9-16
Number of pages8
JournalColloids and Surfaces B: Biointerfaces
Volume147
DOIs
Publication statusPublished - Nov 1 2016

Keywords

  • Adsorption
  • Electrostatic interaction
  • Ellipsometer
  • External electric potential
  • Lysozyme
  • Metal oxide
  • Surface hydroxyl group

ASJC Scopus subject areas

  • Biotechnology
  • Colloid and Surface Chemistry
  • Physical and Theoretical Chemistry
  • Surfaces and Interfaces

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