University of Wisconsin-Madison



Human umbilical vein endothelial cell (HUVEC) tubule morphogenesis (left) or monolayer formation (right) determined by hydrogel stiffness and adhesion ligand density.

Image provided by Eric H. Nguyen.

 

Inducing tissue regeneration

Control over the presence of biologics (e.g. stem cells, growth factors) is a common theme in natural tissue formation, and also an emerging theme in functional tissue regeneration schemes. However, a persistent challenge in tissue regeneration has been to effectively incorporate biologics into medical devices while maintaining optimal physical and chemical properties of the device. In particular, there is often a design trade-off between effective biologic delivery and optimal device physicochemical properties. We have developed a series of strategies to deliver growth factors and stem cells from medical devices. Fundamental mechanisms of protein-biomaterial binding are used to stabilize incorporated biologics and enable uniquely high biological activity. Controllable growth of materials allow for spatial and temporal control over biologic delivery. In addition, delivery can be achieved using a variety of devices, ranging from injectable microparticles to surgical sutures. This “modular” approach results in devices that have optimized physical and biological properties from the macroscopic scale to the molecular scale. We primarily focus on regenerating musculoskeletal tissues and vascular tissue.

 

 

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Figure 1: Multiphoton microscopy of a ligament wound edge 24 hours after injury.

 

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Figure 2: Surgical suture which is incorporated with BSA (green) and lysozyme (red)

 

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Figure 4: Bone-like mineral coating created on poly(lactide-co-glycolide) substrate by incubating in modified simulated body fluid