Simple and effective: Superlubricity behaviour of the G-quadruplex hydrogel with high selectivity for K+ ions based on the ocular environment

• Published in: Friction Vol. 12; no. 11; pp. 2548 - 2562
• Main Authors: Wang, Hongdong, Wu, Jian, Wang, Kunpeng, Su, Yunjuan, Zhang, Xiacong, Liu, Yuhong, Zhang, Jianhua
• Format: Journal Article
• Language: English
• Published: Beijing Tsinghua University Press 01.11.2024; Springer Nature B.V; State Key Laboratory of Tribology in Advanced Equipment,Tsinghua University,Beijing 100084,China%School of Mechatronic Engineering and Automation and Key Laboratory of Advanced Display and System Application,Ministry of Education,Shanghai University,Shanghai 200444,China%Department of Polymer Materials,School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China%State Key Laboratory of Tribology in Advanced Equipment,Tsinghua University,Beijing 100084,China; School of Mechatronic Engineering and Automation and Key Laboratory of Advanced Display and System Application,Ministry of Education,Shanghai University,Shanghai 200444,China
• Subjects: Biocompatibility; Coefficient of friction; Corrosion and Coatings; Diamines; Engineering; Friction; Hydrogels; Lubricants; Lubricating properties; Mechanical Engineering; Nanotechnology; Physical Chemistry; Polyethylene glycol; Research Article; Stress concentration; Surfaces and Interfaces; Thin Films; Three dimensional flow; Tribology; G-quadruplex hydrogel; ocular environment; bio-compatibility; superlubricity
• ISSN: 2223-7690; 2223-7704
• DOI: 10.1007/s40544-024-0898-z

Hydrogels have been the subject of significant research in the field of friction due to their exceptional lubricating properties. In this study, the G-quadruplex hydrogel with high selectivity for K + ions was formed by introducing a mixture of G, 2-formylphenylboronic acid, and polyethylene glycol diamine into simulated artificial tears solution with high transparency, and an ultra-low coefficient of friction (COF) of about 0.004 was obtained based on the simulated ocular environment, thus achieving macroscopic superlubricity. In friction pairs simulating the ocular environment, to assess the frictional performance of the G-quadruplex hydrogel as both a lubricant and a friction pair based on the simulated ocular environment, we conducted experiments considering various factors such as concentration, sliding speed, and stress. Through these experiments, it was found that superlubricity was achieved when the G-quadruplex hydrogel was applied as lubricant or friction pair. This effect was attributed to the three-dimensional network structure and hydrophilicity of the hydrogel, which facilitated the formation of a highly bearing and flowing hydration layer, promoting macroscopic superlubricity. Compared to the G-quadruplex hydrogel with low concentration, the high concentration hydrogel (75 mM) exhibited increased mechanical strength and robustness in superlubricity. Combined with biocompatibility experiments, our synthesized G-quadruplex hydrogel has excellent biocompatibility and offers a novel approach to achieve superlubricity in ocular drug delivery.