Detection of protease activity by FRET using porous silicon as an energy acceptor

This work demonstrates a method for detection of protease activity using porous Si as the energy acceptor in a Fluorescence Resonance Energy Transfer (FRET) assay. A fluorescent dye (fluorescein) is trapped in a porous Si matrix, where its fluorescence is quenched. The dye is trapped using a protein (zein), and the action of proteases (Pronase E) release the dye from the quenching matrix. A strong fluorescence signal appears within 30 min of Pronase E addition. A control with no Pronase E shows little fluorescence, and a control using heat-denatured Pronase E shows approximately 50% of the fluorescence of the active protease. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim