Stratified tissue biofabrication by rotational internal flow layer engineering.

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Bioassembly of layered tissues mimicking human histology is challenging.
• Current bioprinting lacks resolution for microscale cell-width layers, especially with low-viscosity hydrogels like collagen.
• High cell densities are difficult to achieve in stratified tissue engineering.

Purpose of the Study:

• To introduce a novel, low-cost biofabrication technology for creating tuneable, multi-layered tissue-like structures.
• To overcome limitations of existing bioprinting methods in achieving microscale resolution and high cell densities.
• To demonstrate the potential for economically fabricating representative layered tissues.

Main Methods:

• Rotational Internal Flow Layer Engineering (RIFLE) utilizes high-speed rotating tubular molds.
• Small volumes of cell-laden liquids are applied to the inner mold surface, forming thin, gelled layers.
• Layer thickness is controlled by rotational speed, enabling progressive construction of macroscale tubes with discrete microscale strata.

Main Results:

• RIFLE successfully fabricated tuneable, multi-layered tissue-like structures with microscale strata.
• High-density cell layers (10^8 cells/mL) were patterned into heterogeneous constructs.
• Demonstrated tunica media assembly with human smooth muscle cells in cell-width (12.5 µm) collagen layers.

Conclusions:

• RIFLE is an enabling technology for biofabricating composite structures that mimic native stratified tissues.
• The technology facilitates the deposition of discrete microscale layers, crucial for replicating histological features.
• RIFLE offers a cost-effective solution for researchers to create diverse layered tissue models.