Title: Quantitative Phase Imaging as an alternative screening and monitoring method for diabetes

Abstract:

The design and development of transition-metal containing chromophores where changing the oxidation state of the metal(s) alters their optical property are desirable for a variety of applications in chemistry and biology. If one of the optical properties is one-photon fluorescence and the other is second harmonic (two-photon) generation, a desirable change would be alternation between these two optical properties by tuning the oxidation state of the metal center(s) by external means. This will, first of all, make such a chromophore less dependent on the medium or environment which is unlikely to show similar alternating optical response based on the external stimuli. Here we report two Ru based bimetallic complexes, [NC-Ru-(bpy)2-CN-Ru(bpy)2-CN](PF6) (1) and [Ru(bpy)2-bptz-Ru(bpy)2](PF6)2(2) and investigated their second harmonic generation intensity and fluorescence quantum yields after oxidation/reduction of the Ru center(s) electrochemically.  We have determined from cyclic voltammetry (CV) that the first oxidation of 10 to 1+1 occurs at +0.75 V and the second oxidation of 1+1 to 1+2 at +1.34 V.  Similarly the first oxidation of 20 to 2+1 happens at a much higher potential of + 1.95 V and the second oxidation of 2+1 to 2+2 at +2.2V. The spectro-electrochemical studies suggest that the mixed-valent (MV) state of both the complexes exhibit a high energy MLCT band around ~530 nm and an inter-valence charge transfer (IVCT) band in the infrared around ~1200 nm. The MLCT band is attributed to metal d-orbital to ligand π* orbital charge transfer and the IVCT band is assigned to the metal-metal charge transfer from Ru(II) to Ru(III) states. In-situ second harmonic light scattering (SHLS) experiments were carried out in a customized electrochemical cell, where the SH intensity was measured with respect to a particular oxidation state of the metal. We find that the mixed-valent bimetallic complex produces more intense SH light compared to the other oxidation states. In addition, we monitored the change in fluorescence intensity of the bimetallic complexes in different oxidation states

Biography:

Ana Doblas received her BS, Ms.and PhD degrees in Physics from the Universitat de València, Spain, in 2010, 2011 and 2015, respectively. After she finished her PhD work, she joined the Optical Coherence Imaging Laboratory under the supervision of Dr A. Oldenburg (Department of Physics and Astronomy, University of North Caroline in Chapel Hill, U.S.A.) where she did her 1-year Postdoc. Since 2016, she is at the Department of Electrical and Computer Engineering at the University of Memphis (Memphis, Tennessee, U.S.A.). Firstly, as a Research Assistant Professor in the Computational Imaging Research Laboratory (CIRL) and since 2019 as an Assistant Professor and principal investigator of the Optical Imaging Research Laboratory (OIRL). Her current research interests are focused on optical engineering, computational optics and three-dimensional imaging with special interest in the design of novel microscopic imaging systems and their applications. Her final goal is to develop novel optical microscopes that provide us an understanding of unsolved biological questions. Although this topic requires multi-disciplinary approaches from different backgrounds such as Biology, Physics, Microscopy and Informatics, her particular focus is the development of custom optical imaging methods with some insights in image analysis tools to pursue cutting-edge research. Since 2012, she is author of 23 peer-reviewed scientific journals, her work has been presented at over fifty international conferences and she is co-inventor of two US patents.