Microfluidic fabrication of tunable alginate-based microfibers for the
stable immobilization of enzymes
Abstract
Immobilized enzymes have drawn widespread attention due to the enhanced
stability, easy separation from reaction mixture, and the prominent
recyclability. Nevertheless, it is still an ongoing challenge to develop
potent immobilization techniques which are capable of stable enzyme
encapsulation, minimal loss of activity, and modulability for various
enzymes and applications. Here, microfibers with tunable size and
composition were fabricated using a home-made microfluidic device. These
microfibers were able to efficiently encapsulate bovine serum albumin
(BSA), glucose oxidase (GOX) and horseradish peroxidase (HRP). But the
physically adsorbed enzymes readily diffused from microfibers into the
catalytic reaction system. The leakage of enzymes could be substantially
inhibited by conjugating to polyacrylic acid (PAA) and incorporating
into the alginate-based microfibers, enabling stable immobilization,
improved recyclability, and enhanced thermostability. In addition, GOX
and HRP-loaded microfibers were fabricated under the optimized
conditions for the visual detection of glucose using the cascade
reaction of these enzymes, showing sensitive color change to glucose
with concentration range of 0-2 mM. Due to the tunability and
versatility, this microfluidic-based microfiber platform may provide a
valuable approach to the enzyme immobilization for the cascade catalysis
and diagnoses with multiple clinical markers.