**PI: Jeff Weiss**

The broad objective of this project is to study biomechanical interactions of angiogenic microvessels with the extracellular matrix (ECM) on the microscale level. This project is developing techniques to simulate the microscale biomechanical behavior of vascularized collagen gels using Uintah, using volumetric confocal images as the basis for generating the geometry of the computational domain [24] Figure 10. These segmented images will be automatically converted to a computational distribution of material points for MPM simulations. New constitutive models will be used in the MPM code to represent the collagen matrix (based on direct experimental measurements) and the smooth muscle and endothelial cells. Computational algorithms will be developed to represent interface conditions between microvessels and the ECM. The MPM code will be optimized for implicit time integration using quasi-Newton and full Newton solution methods. Development of these simulation technologies will allow computation of local stresses within 3D vascularized constructs and correlation of mechanical local mechanical stresses with microvessel sprouting. Implicit Material Point Method simulation of a microvessel embedded in a collagen matrix (collagen particles not shown, to highlith the non-uniform stress throught the vessel), subject to globally uniform strain. Initial geometry collected via scanning laster confocal micrscopy. Particles are colored according to equivalent stress, the non-uniformity of which is due to the complete geometry along with the difference in material properties between the collagen and vessel.