Date of Graduation

5-2025

Document Type

Thesis

Degree Name

Bachelor of Science in Chemistry

Degree Level

Undergraduate

Department

Chemistry & Biochemistry

Advisor/Mentor

Julie Stenken

Committee Member

Christa Bentley

Second Committee Member

Bin Dong

Third Committee Member

Hugh Churchill

Abstract

Microdialysis is an important sampling technique that has uses in a wide range of disciplines, such as neuroscience and pharmacokinetics. 3D printing aims to address adaptability and customization issues that are present in standard “off-the-shelf” microdialysis probes. This work aims to lay the groundwork for characterizing a 3D printed microdialysis probe designed at the University of Arkansas. One experiment involved measuring solute recovery of caffeine as a function of flow rate of a standard CMA 11 probe to assess its membrane performance. The other goal was to learn about non-specific adsorption tendencies of enzymes (i.e., to what degree proteins stick to surfaces) under stagnant and flow conditions using alkaline phosphatase and glucose oxidase. Initial findings for the CMA 11 probe show that relative recovery of the solute decreases with an increasing flow rate. Mass transport resistance terms were calculated to be 1.09E3 s/cm3 through the dialysate (Rd) and 5.34E4 s/cm3 through the membrane (Rm), with an overall permeability of 0.0162 cm/min. However, the enzyme experiments yielded inconsistent results. It was shown that neither enzyme sticks to plastic syringes under stagnant conditions but do stick to cotton swabs. There was a great degree of variability in the results for the tests under flow conditions, which is likely attributed to run-to-run variability rather than a true loss in enzymatic activity due to adsorption to the syringe or tubing surface. The data collected from this work and further experiments can be used to determine constants specific to the 3D printed device and optimize the design of the prototype.

Keywords

mass transport; permeability; caffeine; alkaline phosphatase; glucose oxidase

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