(51e) Diffusive and Convective Transport of Proteins in Fibrin Gels

The primary cause of heart attacks and strokes is the formation of thrombus fibrin clot in arteries and veins. For decades, researchers have studied how these clots can be safely eliminated from the blood vessels. Many methods for dissolution of the thrombus require delivery of enzymes or drugs to the fibrin clots. In recent years, the use of fibrin gel in medical applications, such as surgical glue and growth factor delivery to wound sites, has expanded extensively. Quantification of diffusion and convection rates within fibrin gels are critical for estimating drug delivery from fibrin gel, controlling temporal and spatial delivery of growth factors for tissue engineering applications, and predicting drug activated dissolution of thrombus. The local drug concentration within gels depends on several factors, including diffusion and convection along with binding to proteins that are strongly bound to the extracellular matrix. If the effects of these factors can be quantified, mathematical transport models can be developed to predict growth factor concentrations within fibrin gels, thereby guiding the delivery of desired amounts of bioactive molecules to and from fibrin gels. The objective of our research is the creation of experimental systems using fluorescence microscopy to determine concentration profiles and mass transport rates of Insulin-like Growth Factor (IGF) in gels. Here we report data for the Darcy permeability of fibrin gels, and the diffusive and convective rates of transport of IGF in these gels. The results are compared with models based on a fiber matrix for the gel and one-dimensional diffusion/convection of IGF through the gel.