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International Journal of Bioprinting 3D bioprinting for musculoskeletal system

prolonged bed rest, heart failure, and chronic obstructive closely mimic the physiology of articular cartilage and
pulmonary disease. Loss of mobility by reduction of show great potential for drug screening.
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muscle mass and function result in poor quality of life and
huge health care costs. There are not many medications 5. Current challenges and future
available for treating skeletal muscle disorders, and perspectives
drug interventions for muscle wasting diseases remain
scarce. To this end, Reyes-Furrer et al. developed a 3D Tissue engineering has made great strides over the past
microphysiological system (MPS) based on human skeletal decade, with recent advances in bio-manufacturing
muscle models made of human skeletal muscle precursor technology, especially 3D bioprinting, being the
cells and Matrigel using drop-on-demand bioprinting. main driving force. 3D bioprinting technologies have
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The bioprinted muscle models demonstrated contractile demonstrated great promise in musculoskeletal tissue
and aligned myofibers after a week of culture. In addition, engineering and drug development. However, there are
contractile force of the models induced by electrical some challenges that should be taken into account for
pulse stimulation was significantly promoted upon the future applications (Figure 7).
intervention of known muscle stimulants, such as caffeine Bioinks possess properties required for 3D-bioprinting
and Tirasemtiv, validating the huge potential of these complex tissues and offer particular biological cues that
models in the screening and development of drugs against facilitate tissue maturation in vitro and in vivo. To generate
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muscle wasting diseases. Infection has always been a huge biologically functional 3D constructs, bioinks must be
challenge for orthopedic surgeons, and the rise of antibiotic- compatible with corresponding bioprinting technology,
resistant strains has further worsened the problem. The which fulfills some critical characteristics, including
development of safe and effective antibiotics is urgently rheology, physicochemical properties, and biological
needed, and cytotoxicity is one of the main concerns for function. With advances in bioprinting technology,
the screening of antibiotics. Bioprinted musculoskeletal especially extrusion-based bioprinting, hydrogel-based
constructs allow low-cost and efficient determination bioinks have become one of the most common options.
of the toxicity of drugs on cells. Datta et al. described a For extrusion-based bioprinting, hydrogel-based bioinks
novel approach to manufacturing scalable tissue strands, serve as a cell carrier to protect cells from shear forces while
which serve as the basic structural unit for bioprinting in providing mechanical support and biological cues to guide
vitro tissue models. As a novel scalable bioink, tissue cell growth and function. Maintaining the balance between
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strands allow scaffold-free bioprinting for rapid generation physicochemical properties and biological functions poses
of biomimetically mature tissues. The diameter of tissue a continuous challenge for 3D bioprinting. More precisely,
strands remains stable, and they can maintain their 3D bioprinting is generally anticipated to produce a
original shape during culture to ensure the repeatability of mechanically robust construct, but the encapsulated cells
the bioprinting process, enabling rapid fabrication of scale- in bioinks typically need mild handling procedures and a
up tissues. These bioprinted scaffold-free cartilage models fairly soft substrate environment. Strong hydrogels are
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Figure 7. Current challenges and potential solutions of 3D bioprinting for musculoskeletal regeneration and disease modeling.

Volume 10 Issue 1 (2024) 95 https://doi.org/10.36922/ijb.1037