Efficient wet-spinning of pre-aligned microtissues for 3D bioprinting complex tissue alignment

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Precise control of cellular alignment is crucial for engineering functional smooth muscle tissues, especially for complex anatomical sites like the gastroesophageal junction (GEJ).
• Existing methods may lack scalability or require specialized equipment for generating aligned microtissues.

Purpose of the Study:

• To develop a scalable wet-spinning technique for producing pre-aligned microtissues (PAMs) using human esophageal smooth muscle cells.
• To demonstrate the utility of these PAMs in 3D bioprinting applications.

Main Methods:

• Immortalized human esophageal smooth muscle cells were embedded in a collagen-alginate core-shell fiber using a wet-spinning approach.
• Fibers were matured, sectioned into uniform PAMs, and characterized for alignment, cell viability, and contractile marker expression.
• PAMs were integrated into a gelatin-methacryloyl bioink for 3D bioprinting.

Main Results:

• The wet-spinning method successfully generated PAMs with preserved cellular alignment and high cell viability.
• Immunofluorescence and gene expression analyses confirmed the presence of key contractile markers.
• 3D bioprinting demonstrated that PAMs maintain alignment along the extrusion path.

Conclusions:

• The developed wet-spinning approach offers an efficient, scalable, and platform-independent method for producing aligned microtissues.
• This technique shows promise for fabricating anisotropic tissues and reconstructing complex muscle structures like the GEJ.