Photo-physical characterization of fluorophore Ru(bpy)32+ for optical biosensing applications

Abstract

We studied absorption, emission and lifetime of the coordination compound tris(2,2′-bipyridyl)ruthenium(II) fluorophore (Ru(bpy)32+) both dissolved in water solutions and dried. Lifetime measurements were carried out using a new detector, the Silicon Photomultiplier (SiPM), which is more sensitive and physically much smaller than conventional optical detectors, such as imager and scanner. Through these analyses and a morphological characterization with transmission electron microscopy, revealed its usability for sensor applications, in particular, as dye in optical DNA-chip technology, a viable alternative to the conventional CY5 fluorophore. The use of Ru(bpy)32+ would solve some of the typical disadvantages related to Cy5’s application, such as self-absorption of fluorescence and photobleaching. In addition, the Ru(bpy)32+ longer lifetime may play a key role in the definition of new optical DNA-chip. Keywords: Tris(2,2′-bipyridyl)ruthenium(II), Fluorophore, Spectroscopy, Lifetime measurements, SiPM, TEM