Display Full Text | Download Full Text
2.72 MB PDF file

Degree

Doctor of Philosophy, University of Akron, Chemistry, 2006.

Abstract

Although electrospun nanofibers have been around for over a century, only recently have researchers begun to take advantage of their unique properties. Small fiber diameters, typically from a few hundred nanometers to 1 micron, afford nanofibers a very high surface area to volume ratio as well as small pore size. Combining these characteristics with those of additives makes them useful for a plethora of applications. Nanofibers were electrospun using Tecophilic® (TP), a polyurethane polymer, as well as cross-linked poly(vinylamine) (PVAm). Two types of structured hydrogels were produced by adding different superabsorbents, Waterlock® (WL) and sodium polyacrylate (SPA), to the spinning solution. The superabsorbent particles were encapsulated in the nanofiber matrix, allowing the particles to absorb copious amounts of water while remaining in a structured environment. The nanofibers containing WL were tested for maximum absorbency of water and synthetic urine, absorbency rate and tensile strength. The nanofibers containing SPA particles were tested for maximum water absorbency and absorbency rate. To improve the surface absorption, a surfactant was added both as a thin top layer and as part of the entire nanofiber construct. Water droplet tests were performed to determine the surface absorptivity. TP was also spun with the NO donor molecules, LPEINO-Ca and LPEINO-Na. Both LPEINO samples were in particle form; the particles were added to the TP solution along with an absorbent material, either WL superabsorbent or microcrystalline cellulose. Quadrol® was added to stabilize the NO donor. Nitric oxide release profiles were performed on the nanofibers in order to determine how much NO was being released from the fibers. Sterilization and stability studies were performed on the fibers to ascertain what effect sterilization has on NO release and at what point the NO donor destabilizes and ceases to be effective. Poly(vinylamine) was crosslinked on the spin creating a water insoluble nanofiber matrix. FITC-labeled albumin was added to the solution prior to spinning. After washing the nanofibers with water, the presence of the FITC-labeled albumin was confirmed using fluorescence. Images of the FITC-labeled albumin were produced using fluorescent microscopy. Results from this experiment indicated that nanofibers could be useful in protein stabilization.

Subject Headings

Chemistry, Biochemistry

Keywords

electrospinning; nanofibers; superabsorbents; nitric oxide donors

Advisor

Daniel J Smith

Pages

141p.

Document number: akron1164646276
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=akron1164646276

This ETD has been downloaded 721 times (through March 2013)