Soft gel breakthrough enables lab-grown slow-twitch muscles

Takasaki, Japan — August 8, 2025 — A team of researchers from the National Institutes for Quantum Science and Technology (QST) and Tokyo Metropolitan University has developed a groundbreaking biomaterial that could revolutionize how we treat muscle degeneration and metabolic disorders. By mimicking the softness and microstructure of slow-twitch muscle tissue, the team successfully cultivated muscle cells in the lab that exhibit the genetic and metabolic traits of slow-twitch fibers—cells crucial for posture, endurance, and glucose regulation.

Slow-twitch muscles are vital for maintaining mobility and metabolic health, especially in aging populations and patients with chronic conditions. However, replicating their unique properties in vitro has long been a challenge. Traditional culture methods fail to reproduce the soft, fibrous environment of native muscle, limiting the ability to study or regenerate these cells effectively.

Led by Dr. Mitsumasa Taguchi, the QST team used a radiation-induced crosslinking technique to create a gelatin-based gel with tunable elasticity and microgrooves. When muscle precursor cells (C2C12 myotubes) were cultured on the softest version of this gel (10 kPa), they expressed genes typical of slow-twitch fibers—such as MYH7 and MYH2—and metabolic markers like GLUT4 and myoglobin. These cells also showed increased levels of PGC-1α, a key regulator of the slow-twitch muscle formation. The studied was published in Scientific Reports on August 8, 2025.

“Our gel provides a microenvironment that closely resembles the physical conditions inside the body,” said Dr. Taguchi. “This allows muscle cells to develop in a way that mirrors natural slow-twitch muscle formation, which has never been achieved with conventional materials.”

The study also found that adding microgrooves to the gel surface enhanced cell alignment and differentiation, although it did not independently trigger the slow-twitch gene expression. This suggests that elasticity is the primary driver of fiber-type shifts, while topography supports structural organization.

The implications of this research are far-reaching. Artificial slow-twitch muscle tissues could be used in regenerative medicine, drug screening, and even muscle transplantation therapies. Because the gel is biocompatible and biodegradable, it may one day serve as a scaffold for repairing damaged muscle in patients suffering age-related muscle loss.

“In the long term, this technology could help extend healthy life expectancy and improve quality of life,” said Dr. Taguchi. “It opens new doors for personalized medicine and advanced biomedical engineering.”

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Reference

DOI: http://doi.org/10.1038/s41598-025-12744-7  

About National Institutes for Quantum Science and Technology, Japan

The National Institutes for Quantum Science and Technology (QST) was established in April 2016 to promote quantum science and technology in a comprehensive and integrated manner. The new organization was formed from the merger of the National Institute of Radiological Sciences (NIRS) with certain operations that were previously undertaken by the Japan Atomic Energy Agency (JAEA).

QST is committed to advancing quantum science and technology, creating world-leading research and development platforms, and exploring new fields, thereby achieving significant academic, social, and economic impacts.

Website: https://www.qst.go.jp/site/qst-english/

About Dr. Mitsumasa Taguchi

Dr. Mitsumasa Taguchi works at Department of Advanced Functional Materials Research, Takasaki Institute for Advanced Quantum Science, QST. He is a leading researcher in the development of biomaterials based on radiation crosslinking technology. His work focuses on precisely controlling the functionality and biocompatibility of polymeric materials such as silicone and collagen through irradiation. He has developed advanced applications including medical devices, biomimetic systems, and muscle model devices. To date, he has published over 120 scientific papers in this field. His pioneering research, integrating radiation chemistry and bioengineering, has attracted significant attention for its innovation and potential impact on next-generation biomedical technologies.

Funding Information

Japan Science and Technology Agency (JST), A-STEP (JPMJTR22U7), ACT-X (JPMJAX2014). Acquisition, Technology and Logistics Agency. Innovative Science and Technology Initiative for Security Type S (JPJ004596).

Japan Society for the Promotion of Science (JSPS) KAKENHI Grants-in-Aid for Scientific Research (22H05054, 23K19377, 24K01998)