Multiphase catalysis is used in many industrial processes; however, the reaction rate can be restricted by the low accessibility of gaseous reactants to the catalysts in water, especially for oxygen-dependent biocatalytic reactions. Despite the fact that solubility and diffusion rates of oxygen in many liquids (such as perfluorocarbon) are much higher than in water, multiphase reactions with a second liquid phase are still difficult to conduct, because the interaction efficiency between immiscible phases is extremely low. Herein, we report an efficient triphase biocatalytic system using oil core-silica shell oxygen nanocarriers. Such design offers the biocatalytic system an extremely large water-solid-oil triphase interfacial area and a short path required for oxygen diffusion. Moreover, the silica shell stabilizes the oil nanodroplets in water and prevents their aggregation. Using oxygen-dependent oxidase enzymatic reaction as an example, we demonstrate this efficient biocatalytic system for the oxidation of glucose, choline, lactate, and sucrose by substituting their corresponding oxidase counterparts. A rate enhancement by a factor of 10-30 is observed when the oxygen nanocarriers are introduced into reaction system. This strategy offers the opportunity to enhance the efficiency of other gaseous reactants involved in multiphase catalytic reactions.

The wetting properties of an electrode surface are of significant importance to the performance of electrochemical devices because electron transfer occurs at the electrode/electrolyte interface. Described in this paper is a low-cost metal oxide electrocatalyst (CuO)-based high-performance sensing device using an enzyme electrode with a solid/liquid/air triphase interface in which the oxygen level is constant and sufficiently high. We apply the sensing device to detect glucose, a model test analyte, and demonstrate a linear dynamic range up to 50 mM, which is about 25 times higher than that obtained using a traditional enzyme electrode with a solid/liquid diphase interface. Moreover, we show that sensing devices based on a triphase assaying interface are insensitive to the significant oxygen level fluctuation in the analyte solution.