Lens-free computational imaging of capillary morphogenesis within three-dimensional substrates

Area of Science:

• Biomedical Engineering
• Cell Biology
• Microscopy

Background:

• Endothelial cells in 3-D matrices form microvessels, crucial for studying angiogenesis and drug discovery.
• Current imaging methods for microvessels have limited field-of-view and depth-of-focus, requiring mechanical scanning and reducing throughput.

Purpose of the Study:

• To develop a lens-free holographic microscopy technique for rapid, large-volume imaging of microvessels.
• To overcome limitations of traditional microscopy in throughput and scanning for angiogenesis studies.

Main Methods:

• Utilized a lens-free holographic on-chip microscopy setup with partially coherent illumination and a CMOS sensor.
• Employed a multi-height phase recovery method for digital reconstruction of in-line holographic images.
• Achieved high spatial resolution (≈ 1.5 μm) over a large field-of-view (24 mm2) without mechanical scanning.

Main Results:

• Successfully imaged microvessel formation in 3-D endothelial cell cultures over extended periods.
• Demonstrated comparable capillary length measurements (within 2%) to traditional microscopy.
• Achieved high-throughput imaging over a large volume (24 mm2) without mechanical scanning.

Conclusions:

• Lens-free on-chip holographic microscopy offers a powerful tool for high-throughput monitoring of microvascular 3-D networks.
• This technique facilitates quantitative analysis of capillary morphogenesis for applications in angiogenesis research and drug discovery.