Label-free nondestructive imaging of vascular network structure in 3D culture.

Three-dimensional (3D) cell culture assays are important tools in the study of vessel assembly. Current techniques for quantitative analysis of vascular network structure have provided important insight into 3D vessel assembly. However, these methods typically require immunohistochemical staining, which requires sample destruction, or fluorescent cell labeling, which may alter cell behavior. The methods also may require sophisticated and expensive microscopy. More robust, easily quantifiable techniques are needed for imaging vascular networks non-invasively. We present an imaging method based on widefield optical sectioning and digital deconvolution (WOSD) that enables imaging of vascular networks in 3D culture without the use of cell labeling, staining, or sample destruction. WOSD can be performed using a standard optical microscope and allows non-invasive 3D monitoring of vascular network formation. This method is illustrated by imaging vascular networks in a 3D hydrogel system. WOSD enabled production of quantifiable 3D images of the network structure. Accuracy of the technique was evaluated by comparing data from WOSD with confocal images of fixed and fluorescently stained samples. Data for vessel length, diameter, and density are consistent between the two methods. The WOSD approach can be applied using standard laboratory equipment and shows great promise for use in analysis of 3D vascular network formation.