Three-dimensional endothelial cell morphogenesis under controlled ion release from copper-doped phosphate glass

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Cell Biology

Background:

• Copper ions are promising angiogenic agents but can be cytotoxic at high concentrations.
• Phosphate-based glasses (PGs) allow for tunable ion release, offering a method for controlled delivery.
• Endothelial cells (ECs) form capillary-like networks, a crucial process in angiogenesis.

Purpose of the Study:

• To investigate the controlled release of copper from phosphate-based glasses (PGs) doped with copper oxide (CuO).
• To evaluate the impact of CuO-doped PGs on the formation of capillary-like networks by endothelial cells (ECs) in a 3D collagen matrix.
• To develop and utilize a 3D morphometric analysis for quantifying EC network development.

Main Methods:

• Formulation and characterization of phosphate-based glasses (50P2O5-30CaO-(20-x)Na2O-xCuO, x=0 and 10 mol%).
• Seeding of SVEC4-10 endothelial cells in 3D type I collagen hydrogels containing PG particles.
• Confocal laser scanning microscopy and 3D morphometric analysis to quantify EC network length, connectivity, and branching.

Main Results:

• Sustained and preferential release of copper was observed from 10% CuO PG, with delayed dissolution at higher concentrations.
• Initial reduction in EC network length was concentration-dependent for both 0% and 10% CuO PGs, but recovered by day 5.
• Cell proliferation, network connectivity, and branching were unaffected by PG content, while metabolic activity was reduced.
• Matrix metalloproteinase (MMP)-1 and -2 gene expression was upregulated by PGs, but did not appear critical for network growth.

Conclusions:

• CuO-doped PGs provide a controlled release of copper ions, modulating endothelial cell behavior in 3D.
• The developed 3D morphometric method enables quantitative assessment of EC network formation.
• These findings support the potential application of CuO-doped PGs as pro-angiogenic biomaterials.