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International

Journal of Bioprinting

RESEARCH ARTICLE
3D-bioprinted in vitro skeletal muscle with

pennate fiber architecture to enhance
contractile function

Lin Gao * , Liuhe Li 1,2 id , Wenze Wu 1,2 id , Junnan Feng 1,2 id , Ziwei Liu 1,2 id ,
1,2 id
Jiankang He 1,2 id , and Dichen Li 1,2 id
1 State Key Laboratory for Manufacturing System Engineering, School of Mechanical Engineering,
Xi’an Jiaotong University, Xi’an, Shaanxi, China
2 National Medical Products Administration (NMPA) Key Laboratory for Research and Evaluation of
Additive Manufacturing Medical Devices, Xi’an Jiaotong University, Xi’an, Shaanxi, China

Abstract

Skeletal muscle tissue engineering (SMTE) has important research value and broad
applicational prospects in areas such as muscle repair, disease modeling, drug
testing, and biohybrid robotics. Despite advances in research on engineered skeletal
muscles, it remains challenging to improve their functional performance, especially
relatively large-sized muscles. Inspired by pennate muscles with a large force output
capacity, a novel in vitro skeletal muscle tissue design mimicking the macro and
microstructures of the gastrocnemius muscle in frogs was proposed and optimized
through simulation. The cell-laden hydrogel was then 3D-bioprinted to fabricate
tissues with fusiform geometry and induced microchannels with a pennate angle
*Corresponding author: of 15°. The morphology, cell status, and contraction performance of 3D-bioprinted
Lin Gao muscle tissues were evaluated after electrical stimulation, which induced the
(gaolin2013@xjtu.edu.cn) directional alignment of myotubes. The results indicated that our 3D-bioprinted
Citation: Gao L, Li L, Wu W, pennate skeletal muscle tissues exhibited high cell viability (79.89%) and alignment
et al. 3D-bioprinted in vitro of muscle fibers (51.93%), with a maximum contraction force of 443.085 μN, almost
skeletal muscle with pennate twice the force of 3D-printed parallel muscle tissues in our study. This work will
fiber architecture to enhance
contractile function. support the exploration of design strategies and rapid manufacturing techniques for
Int J Bioprint. 2024;10(6):4371 . next-generation SMTEs with enhanced functional performance.
doi: 10.36922/ijb.4371
Received: July 29, 2024
Revised: August 22, 2024 Keywords: Skeletal muscle; 3D bioprinting; Pennate muscle;
Accepted: September 3, 2024 Contraction performance
Published Online: September 3,
2024
Copyright: © 2024 Author(s).
This is an Open Access article 1. Introduction
distributed under the terms of the
Creative Commons Attribution Skeletal muscle accounts for approximately 45% of the body’s mass and is capable of
License, permitting distribution,
and reproduction in any medium, generating contractile forces for movements of body parts, supporting internal organs,
provided the original work is and facilitating vital functions, such as chewing and maintaining homeostasis.
1,2
properly cited. Severe muscular defects, involving >20% loss of the original mass, invariably result in
Publisher’s Note: AccScience the loss of innate regenerative capabilities, thereby requiring reconstructive surgical
Publishing remains neutral with procedures, such as autologous muscle transplantation. However, the outcome
3,4
regard to jurisdictional claims in
published maps and institutional of current surgical interventions is limited by inadequate innervation, muscle
affiliations. regeneration, and functional recovery, making the treatment of extensive muscle

Volume 10 Issue 6 (2024) 245 doi: 10.36922/ijb.4371