Protein- and Cell-Resistance of Zwitterionic Peptide-Based Self-Assembled Monolayers: Anti-Biofouling Tests and Surface Force Analysis

Ryongsok Chang; Evan Angelo Quimada Mondarte; Debabrata Palai; Taito Sekine; Aki Kashiwazaki; Daiki Murakami; Masaru Tanaka; Tomohiro Hayashi

doi:10.3389/fchem.2021.748017

Protein- and Cell-Resistance of Zwitterionic Peptide-Based Self-Assembled Monolayers: Anti-Biofouling Tests and Surface Force Analysis

Front Chem. 2021 Oct 6:9:748017. doi: 10.3389/fchem.2021.748017. eCollection 2021.

Authors

Ryongsok Chang¹, Evan Angelo Quimada Mondarte¹, Debabrata Palai¹, Taito Sekine¹, Aki Kashiwazaki², Daiki Murakami², Masaru Tanaka^{2

3}, Tomohiro Hayashi^{1

4

5}

Affiliations

¹ Department of Material Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, Yokohama, Japan.
² Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka, Japan.
³ Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, Fukuoka, Japan.
⁴ JST-PRESTO, Saitama, Japan.
⁵ The Institute for Solid State Physics, the University of Tokyo, Chiba, Japan.

Abstract

Peptide-based self-assembled monolayers (peptide-SAMs) with specific zwitterionic amino acid sequences express an anti-biofouling property. In this work, we performed protein adsorption and cell adhesion tests using peptide-SAMs with repeating units of various zwitterionic pairs of amino acids (EK, DK, ER, and DR). The SAMs with the repeating units of EK and DK (EK and DK SAMs) manifested excellent bioinertness, whereas the SAMs with the repeating units of ER and DR (ER and DR SAMs) adhered proteins and cells. We also performed surface force measurements using atomic force microscopy to elucidate the mechanism underlying the difference in the anti-biofouling property. Our measurements revealed that water-induced repulsion with a range of about 8 nm acts between EK SAMs (immobilized on both probe and substrate) and DK SAMs, whereas such repulsion was not observed for ER and DR SAMs. The strength of the repulsion exhibited a clear correlation with the protein- and cell-resistance of the SAMs, indicating that the interfacial water in the vicinity of EK and DK SAMs is considered as a physical barrier to deter protein and cells from their adsorption or adhesion. The range of the repulsion observed for EK and DK SAMs is longer than 8 nm, indicating that the hydrogen bonding state of the interfacial water with a thickness of 4 nm is modified by EK and DK SAMs, resulting in the expression of the anti-biofouling property.

Keywords: anti-biofouling behavior; atomic force microcopy; biocompatibility; blood compatibility; quartz crystal microbalance; self-assembled monolayers; surface force analysis; zwitterionic peptide.