Three-Dimensional (3D) Printed Microneedles for Microencapsulated Cell Extrusion

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Tissue Engineering

Background:

• Cell-hydrogel based therapies are promising for wound healing.
• Encapsulating cells in hydrogels protects them and allows for controlled delivery.
• Novel delivery systems are needed to maintain cell viability during therapeutic extrusion.

Purpose of the Study:

• To assess the viability of human hepatocellular carcinoma (HepG2) cells encapsulated in alginate capsules after extrusion through a 3D-printed hollow microneedle assembly.
• To evaluate the effect of extrusion on cell payload and hydrogel properties.

Main Methods:

• HepG2 cells were immobilized in atomized alginate capsules.
• A custom hollow microneedle assembly was fabricated using stereolithography.
• Alginate capsules were extruded through the microneedle assembly at a flow rate of 12 mL/min.
• Cell viability was assessed post-extrusion at 2 h and 24 h.
• Hydrogel bioerosion and extrusion yield were quantified.

Main Results:

• No significant difference in HepG2 cell viability was observed between sheared and control samples at 2 h (p=0.14) and 24 h (p=0.5) post-atomization.
• Extrusion yield increased from 21.2% to 56.4% due to hydrogel bioerosion.
• No significant difference in percentage relative payload was found between 2 h (9.9 ± 2.8%) and 24 h (12.2 ± 4.9%) extrusion times (p=0.2628).

Conclusions:

• The extrusion of encapsulated HepG2 cells through a 3D-printed hollow microneedle assembly is feasible.
• The microneedle assembly effectively protects encapsulated cells from shear stress during extrusion.
• This novel approach offers a promising method for cell delivery in wound healing therapies.