Deep UV dispersion and absorption spectroscopy of biomolecules

Abstract

Owing to the high precision and sensitivity of optical systems, there is an increasing demand for optical methods that quantitatively characterize the physical and chemical properties of biological samples. Information extracted from such quantitative methods, through phase and/or amplitude variations of light, can be crucial in the diagnosis, treatment and study of disease. In this work we apply a recently developed quantitative method, called ultraviolet hyperspectral interferometry (UHI), to characterize the dispersion and absorbing properties of various important biomolecules. Our system consists of (1) a broadband light source that spans from the deep-UV to the visible region of the spectrum, and (2) a Mach-Zehnder interferometer to gain access to complex optical properties. We apply this method to characterize (and tabulate) the dispersive and absorptive properties of hemoglobin, beta nicotinamide adenine dinucleotide (NAD), flavin adenine dinucleotide (FAD), elastin, collagen, cytochrome c, tryptophan and DNA. Our results shed new light on the complex properties of important biomolecules.

Unfolding and Aggregation of Lysozyme under the Combined Action of Dithiothreitol and Guanidine Hydrochloride: Optical Studies

“…Recently, there has been growing interest in using interferometry to study the properties of biomolecules. The Mach–Zehnder scheme is especially widely used, and it is used not only in single-beam installations, but also for studies in a wide spectral range [ 49 ]. The data obtained using interferometry are in good agreement with other optical methods, such as circular dichroism [ 50 ], fluorescence [ 51 ], infrared spectroscopy [ 52 ], and so on.…”

All-optical Reflection-mode Microscopic Histology of Unstained Human Tissues

“…The contrast in the PARS images is provided by the 266 nm absorption peak of the sample, primarily highlighting DNA concentration. However, other surrounding species are likely to contribute signal to some degree such as cytochrome, hemoglobin and collagen 30 to name a few as they exhibit non-zero absorption at 266 nm. The high concentration of DNA in cell nuclei facilitates visualization of nuclear morphology, nuclear density, and cellular distribution.…”

“…With PARS, there is an added benefit that erythrocytes are anuclear and do not exhibit significant optical absorption as compared to DNA at 266 nm. Since DNA absorbs 266 nm wavelength significantly more than hemoglobin and other chromophores 30 , the dominant contrast would still be from DNA facilitating the visualization of surgical margins and cellular morphology. Similarly, this work can also be applied to surgical cavities left behind by resections.…”

Prostate cancer histopathology with label-free multispectral deep UV microscopy quantifies phenotypes of tumor grade and aggressiveness

“…Each region was ~1mm X 1.5mm, acquired with a spatial resolution of ~250nm. Multispectral images were taken at four key wavelengths, including 220nm, 255nm, and 280nm, which correspond to strong absorption peaks of proteins and nucleic acids (39). We also included 300nm which does not correspond to an absorption peak of any endogenous biomolecule but serves as an indicator of tissue scattering, which has been applied as a surrogate biomarker of tissue nano-architecture (24,26,(39)(40)(41)(42)(43)(44)(45)(46).…”