Michael Tanes

Master's Defense Presentation

Date: November 1, 2016

Time: 9-11 am

Location: EBB 3029 (Georgia Tech)

Committee:

Younan Xia, PhD (Advisor)

Edward Botchwey, PhD

Zhiqun Li, PhD

Title: Generating a bioactive protein gradient on electrospun nanofiber mats using a bovine serum albumin blocking scheme

Abstract:

Electrospun nanofibers are valuable tools in tissue engineering given the possibilities to mimic various extracellular matrix architectures. However, the incorporation of biochemical cues remains a significant challenge. The biggest challenge is replicating the protein gradients that inspire and direct cell behavior during many of the body's processes. A process was developed to generate a bioactive protein gradient on nanofiber mats. The proposed approach proved to be facile, robust, and conserved the amount of bioactive protein needed to produce a gradient. Bovine serum albumin (BSA) adsorption to polycaprolactone (PCL) nanofibers was found to be a time- and concentration-dependent process. By increasing the volume of solution in a container over time, a BSA gradient was generated across the length of a strip of nanofibers. Vacancies left by the adsorbed BSA on the nanofiber surface were filled-in by a small volume of bioactive protein solution. To test the efficacy of this proposed gradient-generating scheme, dorsal root ganglion (DRG) isolated from chick embryos were cultured on aligned PCL nanofibers with nerve growth factor (NGF) adsorbed homogeneously or as a gradient. DRG on homogeneously adsorbed NGF scaffolds extended neurites of equal length on either side of the DRG cell mass. However, on the scaffolds with an NGF gradient, the neurites extending towards the increasing NGF concentration were significantly longer than neurites extending against the gradient.