Scientists Develop Cartilage-Inspired Supramolecular Hydrogel that Never Loses Its Lubrication

Natural articular cartilage allows joints to move smoothly under repeated loads, but recreating its combination of strength, water-rich lubrication, and durability remains a major challenge for artificial materials. Many hydrogels can hold large amounts of water and reduce friction, but they often lack the mechanical robustness needed for long-term load-bearing use.

In a study published in Supramolecular Materials, researchers from the Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, and collaborating institutions report a new cartilage-inspired supramolecular hydrogel that addresses this long-standing trade-off. The hydrogel, named P(NASC-co-MPC), is built from a strong hydrogen-bonding monomer, N-acryloylsemicarbazide (NASC), and a zwitterionic monomer, 2-methacryloyloxyethyl phosphorylcholine (MPC). After light-triggered polymerization, the material undergoes solvent exchange in water, which reconstructs hydrogen bonds and drives microphase separation inside the network.

“This structure gives the hydrogel two advantages,” explains co-author Desheng Liu. “The NASC-rich network provides mechanical strength, while the MPC units strongly bind water molecules and form a stable, self-replenishing hydration layer at the sliding surface.”

As a result, the optimized hydrogel shows a friction coefficient as low as 0.057 under physiological conditions, close to the performance of natural cartilage. It also maintains stable lubrication under different loads and sliding frequencies, and after 100,000 reciprocating sliding cycles.

“Our design shows that hydrogel materials can achieve both superior lubrication and mechanical strength,” says Liu. “By harnessing zwitterion-driven microphase separation, we engineered a water-rich surface to reduce friction while retaining a robust supramolecular network for load-bearing capacity.”

The researchers also found that the material is compatible with vat photopolymerization 3D printing, enabling the fabrication of customized knee joint prosthesis-like structures. This processability could be important for future patient-specific biomedical implants.

“These results provide a promising foundation for artificial cartilage repair and replacement,” adds corresponding author Xiaolong Wang. “Beyond joint applications, this design concept may also inform the development of anti-adhesion barriers, anti-fouling coatings, and other advanced lubricating materials.”

Contact the author:

Xiaolong Wang, State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China, wangxl@licp.cas.cn

Desheng Liu, State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China, liudesheng@licp.cas.cn

Funder: 

This work was supported by the National Key Research and Development Program of China (2022YFB4600101), the National Natural Science Foundation of China (52505231), the National Science and Technology Major Project (2025ZD01906602), the Research Program of Science and Technology Department of Gansu Province (24JRRA059, 24JRRA044 and 24ZDGA014), the Key Cultivation Projects during the “15th Five-Year Plan” Period of LICP (KCP155B05), the Fundamental Research Special Zone Project of the Lanzhou Institute of Chemical Physics, CAS, and the Special Research Assistant Project of the Chinese Academy of Sciences.

Conflict of interest: 

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

See the article: 

Hu, D.; Liu, D.; Ding, D.; Zhang, X.; Huang, J.; Wang, Y.; Li, B.; Lu, Y.; He, Y.; Wu, T.; Wang, X., Super-hydrated supramolecular hydrogel with persistent minimal friction enabled by zwitterion-driven microphase separation, Supramolecular Materials, Volume 5, 2026, Pages 100137, https://doi.org/10.1016/j.supmat.2026.100137.