A Simple and Sensitive Approach for Real‐Time Sensing of Enzymatically Catalyzed Hydrogelation

Despite the critical role of hydrogels in material science and biotechnology, current methods for analyzing their formation lack real-time monitoring and require complex sample preparation and instrumentation. In this work, an innovative methodology is introduced for the real-time analysis of enzymatically catalyzed hydrogelation. Electrochemical impedance spectroscopy (EIS) coupled with interdigitated electrodes (IDEs) to sense and transduce the gelation reaction of model precursor carboxymethyl cellulose-tyramine (CMC-TA) conjugates that undergoes enzymatic cross-linking by horseradish peroxidase (HRP) and hydrogen peroxide (H$^2$O$^2$). Real-time monitoring involves single-frequency analyses at 3 × 10$^5$ Hz, where the measured impedance consists solely of a resistive component, and the admittance equates to solution conductance. The gelation trajectories for all tested enzymatically cross-linked hydrogel component combinations are determined by substituting the conductance data in the modified Michaelis–Menten kinetic model. Specifically, for CMC-TA cross-linked by HRP, the authors calculate apparent K$_M$ and k$_cat$ values of 82.1 µM and 95.5 s$^{-1}$, respectively. ... mehrThese findings are further validated through rheological characterization, including oscillatory shear measurements and microrheology. Overall, this research paves the way for a streamlined, accurate, and cost-effective approach to controllable enzymatically initiated hydrogel synthesis, enhancing their successful application in various fields ranging from material science to biotechnology.