Influence of growth phase on bacterial cell electrokinetic characteristics examined by soft particle electrophoresis theory

Hiroshi Hayashi, Hiroshi Seiki, Satoshi Tsuneda*, Akira Hirata, Hiroshi Sasaki

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)


The influence of incubation time on the electrokinetic properties of Escherichia coli, Pseudomonas putida, Alcaligenes faecalis, and Alcaligenes sp., was examined by electrophoretic mobility measurements and the results were discussed based on Ohshima's soft particle theory. The electrophoretic mobility of E. coli plotted against incubation time revealed that the mobility gradually increased from the outset of incubation to 7 h, which corresponded to the exponential growth and early stationary phase, and then decreased. For all strains, electrophoretic mobility leveled off to nonzero values in accordance with the increase in ionic concentration, which was a characteristic feature of soft particles. Soft particle analysis was carried out at the outset of incubation and the time when mobility reached a maximum in order to obtain the spatial charge density (ZN) and cell surface softness (1/λ). ZN at the maximum electrophoretic mobility was more negative than that at the outset of incubation for E. coli, P. putida, and A. faecalis, while the ZN of Alcaligenes sp. almost remained unchanged. 1/λ decreased for E. coli, but increased for Alcaligenes sp. and A. faecalis. These findings indicated that the cell growth phase affects both ZN and 1/λ, although the dependencies of these parameters are unique to each bacterial strain.

Original languageEnglish
Pages (from-to)565-568
Number of pages4
JournalJournal of Colloid And Interface Science
Issue number2
Publication statusPublished - 2003 Aug 15


  • Bacterial cell
  • Cell growth phase
  • Cell surface potential
  • Electrophoretic mobility
  • Soft particle theory
  • Zeta potential

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry


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