pH-Responsive and selective protein adsorption on an amino acid-based zwitterionic polymer surface

Shota Fujii, Makoto Kido, Masanao Sato, Yuji Higaki, Tomoyasu Hirai, Noboru Ohta, Ken Kojio, Atsushi Takahara

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)


The synergistic interactions between the α-amine and the carboxylic acid in an amino acid have recently been studied as bio-based zwitterions. Here, we report a new amphiphilic polymer containing glutamic acid grafted to the end of a dodecyl polymer side chain, which contains the α-amine and the γ-carboxylic acid of the glutamic acid moiety. The polymer self-assembled into a multilayered structure in the thin film, and the glutamic acid moieties in the polymer side chains were exposed to the polymer film/water interface. Annealing the sample enhanced the formation of a well-oriented lamellar structure in the films. Due to the presence of the glutamic acid moieties at the interface, the surface charge was controllable by pH in buffer solutions, resulting in zwitterionic character at neutral pH. It has been widely accepted that zwitterionic surfaces can exhibit non-fouling for proteins. Interestingly enough, the polymer film showed charge-selective protein adsorption since the synergistic interaction between the α-amine and the γ-carboxylic acid was weaker than conventional amino acid-based zwitterionic systems. This is due to the separated state of the functional groups by a three carbon spacer.

Original languageEnglish
Pages (from-to)7053-7059
Number of pages7
JournalPolymer Chemistry
Issue number39
Publication statusPublished - Oct 21 2015

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Biochemistry
  • Polymers and Plastics
  • Organic Chemistry


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