Harnessing concerted functions in confined environments: cascading enzymatic reactions in nanofluidic biosensors for sensitive detection of arginine.

We developed an arginine-responsive biosensor by integrating cascade enzymatic reactions into nanochannels functionalized with weak polyelectrolytes, which serve as "reactive signal amplifiers." This approach enhances device performance and broadens the detectable analyte range by generating high local analyte concentrations. The nanofluidic biosensor operates rapidly (<5 minutes) with a low detection limit of 3 μM.