Development and Characterization of Transient Gel-Gap Electrospinning (TGGES) for Advanced Material Applications
Date of Award
12-12-2024
Degree Name
M.S. in Bioengineering
Department
Department of Chemical and Materials Engineering
Advisor/Chair
Russell Pirlo
Abstract
Electrospun nanofiber (ESNF) membranes have attracted widespread interest in many applications due to their advantages in high specific surface area, high porosity, and structural controllability. This study combines gap electrospinning and electrolyte-assisted electrospinning techniques to develop a novel electrospinning approach for producing nanofiber mats of arbitrary geometry. A 3D printed conductive gelatin-based polymer electrolyte (GPE) solution is used as a geometric collector to focus the deposition of electrospun mats. The method utilizes syringe extrusion 3D printing of the GPE solution to produce a shape upon which ESNF are focused. The printable GPE ink is formulated to ensure it possesses the necessary conductivity, shear-thinning, and thixotropic properties. We have developed a gelatin-based GPE ink, enhanced with Laponite to improve shear-thinning properties and salts to increase conductivity. The 3D printing equipment then extrudes the GPE solution on the surface of the target device according to the pre-designed pattern. The optimized GPE solution formulation contained 8% w/v gelatin, 0.2% w/v Laponite, 2 mol/L sodium chloride, and 14.3% v/v glycerol, which was shown to meet the dual requirements of 3D printing and assisting electrospinning. The ink's conductivity was 8.02 S/m measured using a custom developed four-point probe system for gels. Rheological analysis demonstrated that the ink exhibits shear thinning (fluid behavior index n=0.223), which allows GPE ink to maintain a balance between easy extrusion and structural stability. We tested the electrospinning solution used during the experiment and investigated and characterized electrospinning operating parameters to explore several relationships between unrestricted mat diameter (UMD) and electrospinning operating parameters and GPE patterning threshold. The performance of the GPE ink was thoroughly examined experimentally: under the conditions of 25°C and 26% relative humidity, the decay of conductivity resulted in the longest time that GPE-assisted electrospinning could maintain patterning being 45 minutes. Under the condition of a tip-collector distance of 6 cm, GPE-assisted electrospinning can achieve patterning well in the collector diameter range of 0.5-3 cm, obtaining electrospun mats with good uniformity. We compared the electrospinning results of aluminum foil and GPE solution as collectors under the same input parameters and conducted SEM analysis of the obtained ESNF membrane to verify the feasibility of preparing nanofiber membranes through GPE solution. In summary, this work introduces a novel approach for the controlled preparation of ESNF membranes, supported by the development of specialized GPE ink. The study's findings, particularly the parameters and properties accumulated in the process of making the GPE ink work properly, such as the conductivity decay curve, patterning maintenance time, optimal tip-collector distance, and patterning threshold, suggest that these could be a valuable material to promote the development of electrolyte-assisted electrospinning and microfluidic chips, although further research is needed to explore its full potential.
Keywords
electrolyte-assisted electrospinning, additive manufacturing, lab on a chip, organ on chip, gap electrospinning, biointerfaces
Rights Statement
Copyright © 2024, author.
Recommended Citation
Han, Runzhou, "Development and Characterization of Transient Gel-Gap Electrospinning (TGGES) for Advanced Material Applications" (2024). Graduate Theses and Dissertations. 7475.
https://ecommons.udayton.edu/graduate_theses/7475
