Cell-guiding microporous hydrogels by photopolymerization-induced phase separation.

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Polymer Chemistry

Background:

• Microporous scaffolds are crucial for solute transport and cell interactions in 3D cell culture.
• Existing materials lack spatiotemporally controlled pore formation capabilities in aqueous environments.
• Developing instructive scaffolding materials for advanced tissue engineering remains a challenge.

Purpose of the Study:

• To introduce cell-guiding microporous hydrogels fabricated via photopolymerization-induced phase separation (PIPS).
• To demonstrate the ability to control pore size and formation in situ during 3D cell culture.
• To evaluate the efficacy of these hydrogels in supporting cell viability, morphology, and differentiation.

Main Methods:

• Formulation of PIPS resins using ionic polymers (norbornene-functionalized polyvinyl alcohol, dextran sulfate), a di-thiol linker, and a photoinitiator.
• Photocrosslinking to induce phase separation and micropore formation.
• Tuning pore size (2-40 μm) by controlling light intensity, polymer composition, and molecular charge.

Main Results:

• Achieved in situ, light-controlled micropore formation in the presence of living cells.
• Demonstrated high cell viability (>95%) and supported cell spreading and 3D morphogenesis with RGD-functionalized hydrogels.
• Enhanced osteogenic differentiation, matrix mineralization, and collagen secretion in human mesenchymal stromal cells.

Conclusions:

• Photopolymerization-induced phase separation (PIPS) offers a novel method for creating cell-guiding microporous hydrogels.
• These PIPS hydrogels are promising instructive scaffolding materials for 3D cell culture and complex tissue engineering.
• The ability to control pore formation in situ facilitates advanced applications in regenerative medicine.