An enzyme-particle hybrid ink for one step screen-printing and long-term metabolism monitoring.

Targeting the long-term monitoring of biological carbohydrate metabolism, we developed a one-step screen-printing method to fabricate electrochemical sensors using an enzyme microparticle hybrid ink. Most enzymes have low stability in high temperatures and organic solvents, making conventional enzyme modification a bottom-up procedure to be performed after electrode fabrication, resulting in inactivation and detachment in long-term work. Enzyme-loaded microparticles prepared by manganese carbonate co-precipitation had higher stability than free enzymes, which could to be mixed directly with carbon paste for direct screen-printing. Due to the co-printing immobilization and the local hydration environment in enzyme particles, the prepared electrodes exhibited higher long-term operational stability than the conventional multi-step cross-linking method. In the sensing applications, we prepared microparticles loaded with single enzyme (glucose oxidase) and dual enzymes (β-galactosidase and glucose oxidase) for glucose and lactose monitoring, respectively. Both electrodes can accurately measure the consumption of the corresponding carbohydrates throughout the cell or bacterial culture period thus providing a sensing platform for bio-metabolic monitoring and drug screening.