Effect of Hydrophobicity and Charge Separation on the Antifouling Properties of Surface-Tethered Zwitterionic Peptides

Publication year: 2021
Authors: Chuanxi Li 1,2,3,4, Minglun Li 2, Wei Qi 2,3, Rongxin Su 1,3,5, Jing Yu 2

1 - State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
2 - School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
3 - Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, PR China
4 - Petrochemical Research Institute, PetroChina, Beijing 102206, PR China
5 - School of Marine Science and Technology, Tianjin University, Tianjin 300072, PR China

Published in: Langmuir, 2021, Vol. 37(28), p. 8455–8462
doi: 10.1021/acs.langmuir.1c00803

Zwitterionic peptides emerge as a class of highly effective antifouling material in a wide range of applications such as biosensors, biomedical devices, and implants. We incorporated neutral amino acid spacers with different hydrophobicities, including serine (Ser), glycine (Gly), and leucine (Leu), into zwitterionic peptides with lysine–glutamic acid repeating units and investigated the structure and antifouling performance of the zwitterionic peptide brushes by surface plasma resonance, surface force apparatus (SFA), and all-atomistic molecular dynamics (MD) simulation techniques. Our results demonstrate that the hydrophilicity of neutral spacers alters the structure and antifouling performance of the peptide-modified surface. Hydrophilic Ser-inserted peptides reduced the interaction between the peptide monolayer and protein foulants, while hydrophobic Leu significantly increased the protein adhesion. SFA force measurements show that the presence of more spacers would increase the adhesion between the peptide monolayer and the modeling foulant lysozyme, especially for the hydrophobic spacers. MD simulations reveal that hydrophilic Ser spacers retain the hydrophilicity of the peptide monolayer and improve the antifouling performance, and Gly spacers give rise to more interchain cross-links. Leu spacers result in a more hydrophobic peptide monolayer, which leads to dehydration of the peptide monolayer and reduces the antifouling performances.

MP-SPR keywords: adsorption, antifouling, Au sensor slide