Short-wavelength optoacoustic spectroscopy based on water muting

Prakash, J and Seyedebrahimi, MM and Ghazaryan, A and Malekzadeh-Najafabadi, J and Gujrati, V and Ntziachristos, V (2020) Short-wavelength optoacoustic spectroscopy based on water muting. In: Proceedings of the National Academy of Sciences of the United States of America, 117 (8). pp. 4007-4014.

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Abstract

Infrared (IR) optoacoustic spectroscopy can separate a multitude of molecules based on their absorption spectra. However, the technique is limited when measuring target molecules in aqueous solution by strong water absorption at IR wavelengths, which reduces detection sensitivity. Based on the dependence of optoacoustic signal on the temperature of the probed medium, we introduce cooled IR optoacoustic spectroscopy (CIROAS) to mute water contributions in optoacoustic spectroscopy. We showcase that spectral measurements of proteins, lipids, and glucose in the short-wavelength IR region, performed at 4 °C, lead to marked sensitivity improvements over conventional optoacoustic or IR spectroscopy. We elaborate on the dependence of optoacoustic signals on water temperature and demonstrate polarity changes in the recorded signal at temperatures below 4 °C. We further elucidate the dependence of the optoacoustic signal and the muting temperature on sample concentration and demonstrate that changes in these dependences enable quantification of the solute concentration. We discuss how CIROAS may enhance abilities for molecular sensing in the IR. © 2020 National Academy of Sciences. All rights reserved.

Item Type:	Journal Article
Publication:	Proceedings of the National Academy of Sciences of the United States of America
Publisher:	NATL ACAD SCIENCES
Additional Information:	The copyright of this article belongs to NATL ACAD SCIENCES
Department/Centre:	Division of Physical & Mathematical Sciences > Instrumentation Appiled Physics
Date Deposited:	25 Jun 2020 08:09
Last Modified:	25 Jun 2020 08:09
URI:	http://eprints.iisc.ac.in/id/eprint/64818

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