Self-assembly of sustainable plant protein protofilaments into a hydrogel for ultra-low friction across length scales

• Published in: Communications materials Vol. 5; no. 1; pp. 158 - 13
• Main Authors: Pabois, Olivia, Dong, Yihui, Kampf, Nir, Lorenz, Christian D., Doutch, James, Avila-Sierra, Alejandro, Ramaioli, Marco, Mu, Mingduo, Message, Yasmin, Liamas, Evangelos, Tyler, Arwen I. I., Klein, Jacob, Sarkar, Anwesha
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 03.09.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 101/28; 14; 14/3; 631/57/2282; 639/301/923/966; 9/10; Biomedical materials; Chemistry and Materials Science; Coefficient of friction; Contact pressure; Friction; Functional groups; Hydrogels; Hydrophobicity; Lubricants; Lubricants & lubrication; Materials Science; Molecular dynamics; Proteins; Self-assembly; Sustainability; Sustainable materials; Nanoscale biophysics; Self-assembly
• ISSN: 2662-4443; 2662-4443
• DOI: 10.1038/s43246-024-00590-5

Designing plant protein-based aqueous lubricants can be of great potential to achieve sustainability objectives by capitalising on inherent functional groups without using synthetic chemicals; however, such a concept remains in its infancy. Here, we engineer a class of self-assembled sustainable materials by using plant-based protofilaments and their assembly within a biopolymeric hydrogel giving rise to a distinct patchy architecture. By leveraging physical interactions, this material offers superlubricity with friction coefficients of 0.004-to-0.00007 achieved under moderate-to-high (10 2 -to-10 3 kPa) contact pressures. Multiscale experimental measurements combined with molecular dynamics simulations reveal an intriguing synergistic mechanism behind such ultra-low friction - where the uncoated areas of the protofilaments glue to the surface by hydrophobic interactions, whilst the hydrogel offers the hydration lubrication. The current approach establishes a robust platform towards unlocking an untapped potential of using plant protein-based building blocks across diverse applications where achieving superlubricity and environmental sustainability are key performance indicators. Superlubricity is important for energy and biomedical applications but typical building blocks are limited to synthetically-sourced polymeric materials. Here, self-assembly of plant-based protofilaments in biopolymeric hydrogels were engineered offering superlubricity performance.