Microcapillary cell extrusion deposition with picolitre dispensing resolution

Area of Science:

• Bioprinting and Biofabrication
• Cellular Engineering
• Microfluidics

Background:

• Extrusion-based bioprinting is advancing, but limited print resolution hinders single-cell applications.
• Improving resolution requires precision nozzle extrusion, yet its benefits are unclear.

Purpose of the Study:

• Investigate cell organization dynamics during picolitre-precision extrusion.
• Analyze limitations of microcapillary extrusion for cell deposition.
• Provide insights for optimizing high-resolution cell ink extrusion in biofabrication.

Main Methods:

• Utilized an in situ imaging-assisted microcapillary extrusion setup ('Picodis') with picolitre precision.
• Deposited coloring inks and 3T3 fibroblast cells (suspension and pellets).
• Analyzed cell dynamics within the microcapillary tip and during ejection/deposition.

Main Results:

• Cell movements within the tip were governed by laminar fluid flow.
• Key limitations identified: cell sedimentation, aggregation, compaction, and air bubbles.
• Picolitre extrusion offers limited control and is unreliable for precise cell number deposition.

Conclusions:

• High-resolution cell ink extrusion faces significant process limitations.
• Current picolitre extrusion methods may not reliably achieve specified cell counts for biofabrication.
• Understanding these limitations is crucial for optimizing cell-laden construct development.