Adsorption characteristics of various proteins on a metal surface in the presence of an external electric potential

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

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The effect of the properties of a protein on its adsorption to a metal surface in the presence of external electric potential was investigated. Protein adsorption processes at different surface potentials were measured for fifteen types of proteins using an in-situ ellipsometry. The tested proteins were classified into three groups, based on the amount of protein that was adsorbed as a function of the surface potential: In First group of proteins, an increasing trend for the amount adsorbed with a more positive surface potential was found; The amount adsorbed of α-chymotrypsinogen A and ribonuclease A (Second group) were roughly constant and independent of the applied surface electric potentials; In Third group, the amount adsorbed decreased with increasing surface potential. This protein classification was correlated with the isoelectric points of the proteins (First group: ≤9.3; Second group: 9.3–10; Third group: >10). Increasing the pH positively and negatively shifted the surface potentials, allowing ß-lactoglobulin (First group) and lysozyme (Third) to become adsorbed, respectively. The surface potential range for protein adsorption was also markedly shifted depending on the metal substrate type. These findings were interpreted based on the electrostatic interactions among the protein, surface hydroxyl groups, and the applied external electric field.

Original languageEnglish
Pages (from-to)262-268
Number of pages7
JournalColloids and Surfaces B: Biointerfaces
Volume166
DOIs
Publication statusPublished - Jun 1 2018

Keywords

  • Electrostatic interaction
  • Ellipsometer
  • External electric potential
  • Isoelectric point
  • Metal oxide surface
  • Protein adsorption
  • Surface hydroxyl group

ASJC Scopus subject areas

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

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