Vibrational Two-Photon Microscopy for Tissue Imaging: Short-Wave Infrared Surface-Enhanced Resonance Hyper-Raman Scattering

Author: Jacob E Olson1, Jung Ho Yu2, Rebekah L Thimes1, Jon P Camden1
1 Department of Chemistry and Biochemistry, University of Notre Dame Notre Dame, Indiana, United States.
2 Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, CA, United States.
Conference/Journal: J Biophotonics
Date published: 2021 Oct 5
Other: Special Notes: doi: 10.1002/jbio.202100158. , Word Count: 167

Multiphoton microscopies using short-wave infrared (SWIR) radiation offer nondestructive and high resolution imaging through tissue. Two-photon fluorescence, for example, is commonly employed to increase the penetration depth and spatial resolution of SWIR imaging, but the broad spectral peaks limits its multiplexing capabilities. Hyper-Raman scattering, the vibrational analog of two-photon fluorescence, yields spectral features on the order of 20 cm-1 and reporter-functionalized noble metal nanoparticles (NPs) provide a platform for both hyper-Raman signal enhancement and selective targeting in biological media. Herein we report the first tissue imaging study employing surface-enhanced resonance hyper-Raman scattering (SERHRS), the two-photon analog of surface-enhanced resonance Raman scattering. Specifically, we employ multicore gold-silica NPs (Au@SiO2 NPs) functionalized with a NIR-resonant cyanine dye, 3,3'-diethylthiatricarbocyanine iodide (DTTC) as a SERHRS reporter. SWIR SERHRS spectra are efficiently acquired from mouse spleen tissue. SWIR SERHRS combines two-photon imaging advantages with narrow vibrational peak widths, presenting future applications of multitargeted bioimaging. This article is protected by copyright. All rights reserved.

Keywords: SWIR; Short-wave infrared; bioimaging; multiphoton.

PMID: 34609064 DOI: 10.1002/jbio.202100158