Microfluidic direct writer with integrated declogging mechanism for fabricating cell-laden hydrogel constructs.

Area of Science:

• Biomaterials Engineering
• Tissue Engineering
• Microfluidics

Background:

• Achieving controlled cell distribution and nutrient supply in 3D hydrogel scaffolds is crucial for mimicking in vivo conditions.
• Conventional fabrication methods struggle to provide the necessary control for complex scaffold architectures.
• Efficient nutrient and media exchange is vital for cell viability and function within engineered tissues.

Purpose of the Study:

• To develop and demonstrate a microfluidic direct writer (MFDW) for fabricating 3D cell-laden hydrogel structures.
• To enable precise control over scaffold architecture, fiber diameter, and cell encapsulation.
• To create constructs with integrated openings for enhanced media exchange and improved cellular microenvironments.

Main Methods:

• A microfluidic direct writer (MFDW) utilizing coaxial streams of cell-laden sodium alginate and calcium chloride solutions was designed.
• Fiber diameter was controlled by adjusting the ratio of volumetric flow rates.
• A motorized stage synchronized with fiber fabrication speed was employed for automated layer-by-layer construction.
• Optimization of head geometry, flow rates, and solution viscosity addressed challenges like curling and bulging.
• A declogging conduit was integrated for continuous and reliable operation.

Main Results:

• The MFDW successfully fabricated 3D cell-laden hydrogel structures with controlled fiber diameters.
• Layer-by-layer assembly of 3D constructs with encapsulated cells was demonstrated.
• The fabrication of structures using multiple distinct hydrogel fibers by alternating solutions was achieved.
• The system showed reliability for continuous use, preventing clogging issues.
• The MFDW allows for rapid and easy construction of complex 3D scaffolds.

Conclusions:

• The microfluidic direct writer (MFDW) offers a versatile platform for advanced 3D hydrogel scaffold fabrication.
• This technology provides enhanced control over scaffold architecture, crucial for tissue engineering.
• The MFDW facilitates the creation of constructs with improved nutrient supply and cellular environments.
• The developed method supports the fabrication of multi-material and multi-cellular 3D constructs for diverse tissue engineering applications.