4. Conclusions
In this study, a home-made co-flow microfluidic chip was constructed to prepare the alginate-based microfibers which composition, size, and degree of crosslinking was feasibly tunable. These microfibers were capable of effectively absorbing BSA and enzymes. To reduce the leakage of enzymes from microfibers in the catalytic reaction solution, GOX was covalently grafted to PAA and formed microfibers with alginate. The resulting microfibers enabled stable encapsulation and excellent repeating use of enzymes. Over 85% of the activity remained after seven cycles of reuse. Moreover, GOX-PAA immobilized microfibers exhibited enhanced thermostability than free GOX. Two enzymes (GOX and HRP) were loaded in microfibers for the visual detection of glucose using the cascade reaction of these enzymes. The enzyme ratio-optimized microfibers demonstrated rapid and sensitive color change upon addition of glucose with concentration of 0-2 mM. Due to the feasibility and tunability, this versatile microfiber platform may have great potential in the immobilization of various enzymes for catalysis and simultaneous detection of multiple diagnostic markers.