Lateral spread of an amplification signal using an enzymatic system on a conductive surface

In this letter, we report a novel signal amplification phenomenon that rapidly and dramatically increases both the magnitude and the lateral extent of the original signal. This phenomenon utilizes an enzyme immobilized on a conductive surface to generate amplified signals at locations remote from the original site of enzyme activity. The result is demonstrated on a microfluidic platform using the established precipitating enzyme-substrate system of horseradish peroxidase (HRP) and 3,3',5,5'-tetramethylbenzidine (TMB) on a surface plasmon resonance (SPR) imaging system.