Local tissue geometry determines contractile force generation of engineered muscle networks

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Skeletal Muscle Physiology

Background:

• Skeletal muscle tissue engineering faces challenges in creating dense, aligned, and mature myofibers.
• Understanding structure-function relationships in engineered muscle is limited.
• Previous work created muscle networks with elliptical pores using elastomeric molds.

Purpose of the Study:

• To investigate how varying pore elongation in engineered muscle networks impacts morphology and contractile function.
• To determine the effects of pore geometry on myofiber alignment, formation, and force production.

Main Methods:

• Fabrication of engineered muscle sheets with elliptical pores using elastomeric molds and fibrin gel.
• Systematic variation of pore elongation within the muscle network constructs.
• Assessment of myofiber morphology, alignment, and contractile force production.

Main Results:

• Increased pore elongation significantly enhanced myofiber alignment and formation efficiency.
• Total contractile force increased despite a reduction in tissue volume.
• Beyond a threshold pore length, enhanced force was primarily due to improved myofiber formation, not just alignment.

Conclusions:

• Local tissue geometry, specifically pore elongation, directly influences engineered muscle structure and function.
• Optimizing pore geometry offers a strategy to enhance the contractile output of engineered muscle.
• These findings support the use of engineered muscle networks for in vitro studies and in vivo muscle repair.