An optical device is formed by hot stamping a demetallized hologram to an optically variable foil or to a coating of optically variable ink. Specifically, the invention relates to labeled-imidazole-PEG compounds, such as nucleosides, nucleotides, and nucleic acids incorporating such compounds, and methods utilizing such compounds. Wide channels and knife edges can be made of desirable material, for example 304 stainless steel. The optical reader may be coupled to the body and adapted to analyze the analyte on the test strip.