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Broadband stimulated Raman imaging based on multi-channel lock-in detection for spectral histopathology

Authors :
Alejandro De la Cadena
Federico Vernuccio
Andrea Ragni
Giuseppe Sciortino
Renzo Vanna
Carino Ferrante
Natalia Pediconi
Carlo Valensise
Luca Genchi
Sergey P. Laptenok
Andrea Doni
Marco Erreni
Tullio Scopigno
Carlo Liberale
Giorgio Ferrari
Marco Sampietro
Giulio Cerullo
Dario Polli
Source :
APL Photonics, Vol 7, Iss 7, Pp 076104-076104-12 (2022)
Publication Year :
2022
Publisher :
AIP Publishing LLC, 2022.

Abstract

Spontaneous Raman microscopy reveals the chemical composition of a sample in a label-free and non-invasive fashion by directly measuring the vibrational spectra of molecules. However, its extremely low cross section prevents its application to fast imaging. Stimulated Raman scattering (SRS) amplifies the signal by several orders of magnitude thanks to the coherent nature of the nonlinear process, thus unlocking high-speed microscopy applications that provide analytical information to elucidate biochemical mechanisms with subcellular resolution. Nevertheless, in its standard implementation, narrowband SRS provides images at only one frequency at a time, which is not sufficient to distinguish constituents with overlapping Raman bands. Here, we report a broadband SRS microscope equipped with a home-built multichannel lock-in amplifier simultaneously measuring the SRS signal at 32 frequencies with integration time down to 44 µs, allowing for detailed, high spatial resolution mapping of spectrally congested samples. We demonstrate the capability of our microscope to differentiate the chemical constituents of heterogeneous samples by measuring the relative concentrations of different fatty acids in cultured hepatocytes at the single lipid droplet level and by differentiating tumor from peritumoral tissue in a preclinical mouse model of fibrosarcoma.

Details

Language :
English
ISSN :
23780967
Volume :
7
Issue :
7
Database :
Directory of Open Access Journals
Journal :
APL Photonics
Publication Type :
Academic Journal
Accession number :
edsdoj.b717adcfe216410fb66c53f294e9b26d
Document Type :
article
Full Text :
https://doi.org/10.1063/5.0093946