Chemosensors Based on Metal-Dye Complexes for Bioanalytes

Multicomponent chemosensors were prepared by mixing the rhodium(III) complex [(η5-C5Me5)RhCl 2]2, nickel(II) chloride and/or copper(II) chloride with commercially available dyes in buffered aqueous solution. The sensors were used to detect various biomolecules, which interact with the components of the sensing ensemble and alter the composition, and hence the color of the sample. The sensors were analyzed by UV/Vis spectroscopy. A mixture of [(η5-C5Me5)RhCl 2]2, three dyes and pyrophosphate was employed to determine in retrospect the time at which the target molecules ADP and ATP were added to the sensing ensemble. An artificial neural network was used to correlate absorbance data with analyte addition times. Dynamic combinatorial libraries of metal-dye complexes prepared from NiCl2, CuCl2 and three dyes were used to distinguish between mixtures of the peptide hormones angiotensin I and angiotensin II. The discriminative power of the sensor was increased by analyzing samples in a time-resolved fashion. Nine primary amines were identified in a sensing ensemble, where amines were first combined with pyridine-2-aldehyde in the presence of NiCl2 or CuCl2, in order to obtain metal-stabilized imine mixtures. A colorimetric output was generated by adding a dye. In an approach to sense conventional sugars in an indicator displacement assay, sugars were transformed in situ into sugar imines prior to the sensing experiment.