# Magnetic Bioprinting and Actuation of Stretchable Muscle Tissue

## TL;DR

Researchers developed a magnetic bioprinting method to create stretchable muscle tissues that maintain shape and improve function when stretched.

## Contribution

A novel magnetic bioprinting approach enables scaffold-free, shape-controlled, and stretchable muscle tissue engineering.

## Key findings

- Magnetic bioprinting preserves tissue shape and promotes anisotropic muscle cell differentiation over two weeks.
- Mechanical stretching of magnetic muscle tissues up to 100% enhances maturation and contractility.
- The method shows promise for advanced muscle-on-chip systems and complex tissue engineering.

## Abstract

Engineering tissues with precise, long‐lasting shapes and the capability for mechanical stimulation remains challenging. This study addresses this challenge by developing a next‐generation magnetic bioprinting approach to create anisotropic, shape‐controlled, scaffold‐free, and stretchable skeletal muscle constructs. Murine skeletal muscle cells and human induced pluripotent stem cell‐derived skeletal muscle cells, labeled with iron oxide nanoparticles, are magnetically bioprinted into wrench‐shaped tissues. Their magnetic properties allow these tissues to be clipped onto magnetic needles, preserving their shape over two weeks of culture while promoting anisotropic differentiation and myoblast fusion. Additionally, the magnetic tissues can be stretched by up to 100%, enhancing their anisotropy and improving muscle maturation. This magnetic toolbox demonstrates significant advancements in muscle tissue engineering, as evidenced by enhanced indicators of myoblast differentiation, including cell fusion, increased myogenic maturation, and contractility. These findings highlight the potential of magnetic‐based techniques for developing advanced muscle‐on‐chip systems and other complex tissue constructs.

Human and murine myoblasts labeled with iron oxide nanoparticles are magnetically bioprinted into wrench‐shaped tissues, which are then anchored between two magnetic needles. Mechanical stretching of these tissues enhances both their maturation and functional performance.