Date Approved

9-18-2024

Embargo Period

9-18-2024

Document Type

Thesis

Degree Name

Master of Science (M.S.)

Department

Biomedical Engineering

College

Henry M. Rowan College of Engineering

Advisor

Vince Beachley, Ph.D.

Committee Member 1

Sebastián Vega, Ph.D.

Committee Member 2

David Fuller, M.D.

Keywords

Fabrication, Hydrogel, Nanofibers, Nerve Graft Conduits, Scaffold

Subject(s)

Nerves, Peripheral; Solid freeform fabrication

Disciplines

Biomedical Engineering and Bioengineering | Materials Science and Engineering | Medicine and Health Sciences

Abstract

Nerve graft conduits (NGCs) are a rapidly advancing field for treating peripheral nerve injuries that aim to guide the growth of regenerating axons across damaged gaps. A more effective NGC can be manufactured by combining the use of nanofibers to act as guidewires within a 3-D hydrogel that imitates the extracellular matrix of nerve tissue. Several methods have been developed to embed aligned nanofibers in an ordered architecture within a hydrogel matrix. The first method involves layer-by-layer additive manufacturing to create NGCs with rows of polycaprolactone (PCL) nanofibers surrounded by a gelatin methacrylate (GelMe) hydrogel in a 3-D structure. A second method where individual films of fibers embedded in hydrogel were rolled was developed, introducing void space throughout the scaffold that allows for easier cell infiltration. The final method uses a sacrificial hydrogel scaffold template to manufacture the scaffold. The desired hydrogel is infiltrated into the template hydrogel and crosslinked before the template’s removal, allowing for a much wider variety of hydrogels such as pH or ion responsive materials. It was found that GelMe and hyaluronic acid-based hydrogels limited axon infiltration in a sciatic nerve gap model at the studied weight percent and degrees of crosslinking. This result highlights how the infiltration manufacturing approach may be critical for fabricating aligned nanofiber-hydrogel composite grafts from next generation hydrogels.

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