Technique for Rapidly Forming Networks of Microvessel-Like Structures

Area of Science:

• Biomaterials Engineering
• Tissue Engineering
• Cellular Biology

Background:

• Organ-blood barriers are critical for vascularized organ function, drug transport, and disease pathology.
• Existing in vitro models struggle to replicate complex microvessel networks beyond capillary size.
• Fabrication challenges limit the creation of physiologically relevant vascular structures.

Purpose of the Study:

• To present a novel, rapid method for fabricating microvessel-like networks using sacrificial alginate structures.
• To enhance the accuracy of in vitro tissue models for studying organ-blood barriers.
• To provide a reproducible and transferable technique for tissue engineering applications.

Main Methods:

• Encapsulation of endothelial cells within short, sacrificial alginate threads.
• Embedding of cell-laden alginate threads within a collagen gel matrix.
• Enzymatic degradation of alginate to form hollow, cell-seeded channels within the gel.
• Utilized a 3D-printed coaxial extruder and syringe pumps for thread fabrication.
• Investigated the viability of cryopreserved cell-laden alginate threads.

Main Results:

• Successfully formed a network of hollow, cell-seeded channels surrounding a perfusable central channel.
• The fabrication method is repeatable, transferable, and amenable to scale-up.
• Cryopreservation of alginate threads did not significantly impact cell viability.
• Cell survival was enhanced under static conditions within millifluidic devices.

Conclusions:

• The sacrificial alginate thread method offers a viable approach for creating complex microvessel networks in vitro.
• This technique holds significant potential for advancing tissue engineering and organ-on-a-chip applications.
• The ability to freeze threads simplifies handling and enables future large-scale implementation.