Cell flocculation and phase-separation support macro-scale tissue slab construction in a scaffold-free manner

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Cell Biology

Background:

• Scaffold-free macro-scale tissue creation is difficult due to challenges in achieving cohesive cell binding.
• Adherent cells in attachment-deprived conditions typically form micro-spheroids, not cohesive tissue.

Purpose of the Study:

• To develop a novel scaffold-free method for creating macro-scale tissues.
• To investigate the role of cellular flocculation and phase separation in tissue formation.
• To assess the functionality and microstructure of the resulting scaffold-free tissues.

Main Methods:

• Cells were flocculated with 0.1% hyaluronic acid and subjected to phase separation using 5% polyethylene glycol (PEG).
• Incubation in PEG-containing media induced macromolecular crowding, promoting cell-ECM interactions.
• Macro-scale, slab-like tissues were constructed using bone marrow-derived multipotent stem cells (BM-MSCs) or chondrocytes.

Main Results:

• The method successfully produced single, cohesive tissue masses without scaffolds.
• The resulting tissues exhibited high cellularity and a stabilized microstructure.
• Tissues demonstrated excellent functionality, particularly superior in vitro chondrogenic potential.

Conclusions:

• Cellular flocculation and phase separation can effectively control cell aggregation for scaffold-free tissue engineering.
• This technique enables the creation of macro-scale, slab-like tissues with preserved cell functionality.
• This represents a significant advancement in scaffold-free tissue construction, especially for cartilage regeneration.