Integrated On-Chip 3D Vascular Network Culture under Hypoxia

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Cell Biology

Background:

• Developing functional vascular networks in vitro is crucial for regenerative medicine and disease modeling.
• Long-term 3D cell culture requires controlled microenvironments that mimic physiological conditions.
• Oxygen levels (normoxia and hypoxia) significantly influence vascular development.

Purpose of the Study:

• To develop and evaluate a portable poly(dimethylsiloxane)/polymethylmethacrylate (PDMS/PMMA) device for long-term 3D vascular endothelial cell culture.
• To investigate the effects of transitioning between normoxia and hypoxia on vascular network formation and maturation.
• To optimize in vitro vascular development using controlled oxygen microenvironments.

Main Methods:

• Fabrication of a portable PDMS/PMMA device with nested reservoirs for on-chip incubation.
• Implementation of a bicarbonate/ascorbate buffer system for stable pO2 and pCO2 control (4.91% pO2, 5.19% pCO2).
• Long-term (up to 10 days) 3D culture of vascular endothelial cells under dynamic oxygen conditions (normoxia/hypoxia).

Main Results:

• The device enabled stable on-chip incubation and long-term culture of vascular endothelial cells.
• A 72-hour normoxic pre-incubation followed by hypoxic culture significantly enhanced cell viability, network formation, lumen size, and stability.
• Analysis of network parameters (mesh area, length, branches) revealed differential effects of oxygen treatments on vessel maturity.

Conclusions:

• The developed PDMS/PMMA device provides a robust platform for long-term 3D vascular network development.
• Controlled transitions between normoxia and hypoxia, particularly with a normoxic pre-conditioning phase, are critical for improving in vitro vascular development.
• Hypoxia's effect is dependent on vessel maturity, offering a tunable parameter for enhancing engineered vascular tissues.