Kinetics of Enzymatic Reactions at the Solid/Liquid Interface in Nanofluidic Channels.

Nanostructures can realize highly efficient reactions due to their structural advantages. However, the mechanism of accelerating enzyme reactions in a nanospace is still unknown from a kinetic perspective because it is difficult to control a well-defined nanospace, enzyme density, and reaction time. Here, we investigated kinetic parameters of an immobilized enzyme in micro- and nanochannels using nanofabrication, partial enzyme patterning, fluidic control, and a high sensitivity detection system. Devices with channel depths of 300 nm, 4.4 μm, and 13.6 μm were fabricated. Kinetic parameters were determined by the Michaelis-Menten model. Compared to the bulk reaction, all k cat s for immobilized enzyme reactors were decreased, although the k cat s were approximately the same for the immobilized enzyme reactors of different depths. An ultrafast enzyme reaction could overcome the drawback due to immobilization by an increase of the apparent [ E ] 0 due to the decreased channel depth.