Abstract: A method and recombinant assay cell for detecting growth hormone releasing hormone (GHRH) in a sample, the method includes exposing a recombinant cell to the sample and measuring transcription of a reporter gene. A suitable recombinant cell includes a reporter gene operatively connected to a cAMP-responsive promoter and a GHRH-responsive protein whose binding to GHRH induces the production of cAMP. GHRH present in an assay sample results in the GHRH-responsive protein activating the production of cAMP, which then activates the c-AMP-responsive promoter to express the reporter protein. The amount of reporter protein produced is quantitatively correlated to the amount of GHRH in the sample. In one embodiment, the protein is a cell surface receptor for GHRH.

Abstract: An n-type silicon (Si) wafer is galvanostatically etched in a hydrofluoric acid (HF)-containing solution while being illuminated with a 300 watt tungsten light source to form porous silicon with luminescent properties. Photoluminescence of the porous silicon is monitored using a short wavelength visible or ultraviolet light source and a monochromator/CCD detector assembly. Upon exposure to organic solvents, the photoluminescence is quenched. Within seconds of removal of the solvent, the original intensity is recovered and further exposure of the porous silicon to organic solvents will again result in quenching of the luminescence.