Contact based rigid pin tool technology is utilized to print one or more indicator chemistries on an optical array or a disposable sheath configured on such arrays. Each indicator chemistry contains predetermined material, such as, light energy absorbing dye(s), optically responsive particles, etc., whose optical characteristics change in response to the target ligand or analyte. By spectrally monitoring such changes using fluorescence and/or absorption spectroscopy, detection and/or quantitation of the target ligand or analyte can be obtained.