Microfluidic Chip-based Fabrication Of Hollow Alginate Microfiber For Enzyme Entrapment And Reaction

Abstract

This thesis demonstrates a simple process to generate alginate hollow microfibers by using a non-lithographic PDMS microfluidic device. The microfluidic device was fabricated by a novel template method in a wet lab without the support of any conventional lithography techniques. The relationships of the flow rate and the diameter of hollow alginate fibers were characterized. It was found that the outer diameter of the alginate hollow fiber was independent of the flow rate, but the core flow and sheath flow played an important role to control the internal diameter and the wall thickness of the alginate hollow microfiber. At a constant sheath flow and at increasing core flow rates, the internal diameters increased and the wall thicknesses decreased. At a fixed core flow, with increasing sheath flow rates, the internal diameters decreased and the wall thicknesses increased. The fabricated alginate hollow microfiber was then used as a bioreactor. Glucose oxidase (GOx) was chosen as a model enzyme that was entrapped in the hollow microfibers. The GOx enzyme activity was investigated by a colorimetric assay. This showed that a small internal core and a thick wall directly affected the enzyme encapsulation efficiency, enzymatic activity, and enzyme leakage. In addition, the metal ions present in an enzyme storage solution could act as activators or inhibitors changing the enzyme activity.