Detection of trophic factor activated signaling molecules in cells by a compact fiber-optic sensor

This paper describes a highly sensitive method to detect trophic factor activated signaling molecules in cells using a compact fiber optic biosensor. The method is demonstrated by quantitative detection of phosphorylation of signal transducers and activators of transcription 3 (STAT3) in neuroblastoma cells. A single fiber-optic probe based on total internal reflection fluorescence sensing system is used. A 405 nm diode laser is used for evanescent wave excitation of immobilized labelled analyte on the probe surface. A compact charged coupled device (CCD) based spectrometer is used for recording the fluorescence signal. The method is two orders of magnitude more sensitive than the Western blotting technique. (C) 2004 Elsevier B.V. All rights reserved.