Sub millimetre flexible fibre probe for background and fluorescence free Raman spectroscopy

Yerolatsitis, Stephanos; Kufcsák, Andras; Ehrlich, Katjana; Wood, Harry A. C.; Fernandes, Susan; Quinn, Tom; Young, Vikki; Young, Irene; Hamilton, Katie; Akram, Ahsan R.; Thomson, Robert R.; Finlayson, Keith; Dhaliwal, Kevin; Stone, James M.

doi:10.1002/jbio.202000488

Cited by 4 publications

(12 citation statements)

References 20 publications

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“…The multimode endcap and the cleaved cross section of the fibre used for Raman spectroscopy are shown in Figures 1c and d, respectively. The Raman fibre is more fully described and evaluated in [30,31]. A central ring of air-filled capillaries forms an open-boundary single-mode negativecurvature hollow-core to deliver 785 nm excitation light to the distal end.…”

Section: Optical Fibresmentioning

confidence: 99%

“…al. [30]. For excitation we used a continuous wave 785 nm 20 mW diode laser source, filtered to 1 nm bandwidth.…”

Section: Optical Systemsmentioning

confidence: 99%

“…By subtracting one from the other, the fluorescence signal is cancelled while the original Raman spectrum can be restored from the difference spectrum. However, as the fluorescence contribution often varies in the two raw spectra, additional processing steps are required to get clean Raman signatures, these are more fully described in [30,42]. Here, we recorded spectra in 5 s long acquisitions, using two laser sources thermally tuned to 784 and 785 nm.…”

Section: Human Lung Tissue Optical Biopsymentioning

confidence: 99%

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Tri‐mode optical biopsy probe with fluorescence endomicroscopy, Raman spectroscopy, and time‐resolved fluorescence spectroscopy

Wood

Ehrlich

Yerolatsitis

et al. 2022

Journal of Biophotonics

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Section: Optical Fibresmentioning

confidence: 99%

“…al. [30]. For excitation we used a continuous wave 785 nm 20 mW diode laser source, filtered to 1 nm bandwidth.…”

Section: Optical Systemsmentioning

confidence: 99%

Section: Human Lung Tissue Optical Biopsymentioning

confidence: 99%

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Tri‐mode optical biopsy probe with fluorescence endomicroscopy, Raman spectroscopy, and time‐resolved fluorescence spectroscopy

Wood

Ehrlich

Yerolatsitis

et al. 2022

Journal of Biophotonics

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“…Within reflectance, Raman scattering detection is a valuable tool to perform histochemical analysis in a label-free, non-invasive, and non-destructive way [121,127,128]. However, one of the challenges of Raman-based probes is that the signal-to-noise ratio is weak [129].…”

Section: Reflectance Probesmentioning

confidence: 99%

“…A background Raman signal is generated when a narrow pump (i.e., laser) passes through a silica fibre. This signal is large enough to overwhelm any signal collected from the biological sample [128,130]. Hence, the background Raman signal and the reflected pump signal must be prevented from being collected.…”

Section: Reflectance Probesmentioning

confidence: 99%

Recent Advances in Biomedical Photonic Sensors: A Focus on Optical-Fibre-Based Sensing

Ochoa

Algorri

Roldán-Varona

et al. 2021

Sensors

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In this invited review, we provide an overview of the recent advances in biomedical photonic sensors within the last five years. This review is focused on works using optical-fibre technology, employing diverse optical fibres, sensing techniques, and configurations applied in several medical fields. We identified technical innovations and advancements with increased implementations of optical-fibre sensors, multiparameter sensors, and control systems in real applications. Examples of outstanding optical-fibre sensor performances for physical and biochemical parameters are covered, including diverse sensing strategies and fibre-optical probes for integration into medical instruments such as catheters, needles, or endoscopes.

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Distinguishing bacteria from minerals in a layered sample using time-resolved Raman spectroscopy and global analysis

Mooij

Stokkum

Davies

et al. 2022

J. Opt.

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Mars is one of the prime candidates in the search for extraterrestrial life. At the most comparable terrestrial Martian analogue sites, life often occurs in endolithic form; i.e., hiding below the surface. To detect biomarkers of endolithic life, the two most promising options are drilling or measuring through the surface, the latter being less invasive and preferable. Raman spectroscopy is an established chemical identification method, and advanced Raman modes have been developed for sub-surface analysis. Time-resolved Raman spectroscopy (TRRS), based on picosecond pulsed excitation and a gated intensified CCD detector, adds the capability of fluorescence suppression and depth selection. This paper focuses on the separation of layers with time differences that are much smaller than the 200 ps (FWHM) gating time of the detector. As an analogue for endolithic life on Mars, D. radiodurans bacteria were measured through a 2.5 mm and 7.5 mm top layer of translucent calcite. TRRS spectra were recorded in a backscattering geometry, while stepwise increasing the detector delay in 25 ps steps. Through both of these layers, the Raman spectrum of the bacteria’s carotenoids could be detected. Global analysis was used to model a complete time-resolved spectrum of the sample. Using this analysis, the signals could be separated into three components: mineral Raman, bacterial Raman and bacterial fluorescence. The model also corrects for gating differences across the horizontal axis of the ICCD camera. With this approach well-separated Raman spectra were obtained even for the 2.5-mm calcite layer despite the temporal separation of approximately 20 ps, which is much shorter than the 200 ps detector gating time. TRRS could be a suitable approach for non-invasive detection of extraterrestrial subsurface biomarkers.

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Sub millimetre flexible fibre probe for background and fluorescence free Raman spectroscopy

Abstract: Using the shifted-excitation Raman difference spectroscopy technique and an optical fibre featuring a negative curvature excitation core and a coaxial ring of

Cited by 4 publications

References 20 publications

Tri‐mode optical biopsy probe with fluorescence endomicroscopy, Raman spectroscopy, and time‐resolved fluorescence spectroscopy

Tri‐mode optical biopsy probe with fluorescence endomicroscopy, Raman spectroscopy, and time‐resolved fluorescence spectroscopy

Recent Advances in Biomedical Photonic Sensors: A Focus on Optical-Fibre-Based Sensing

Distinguishing bacteria from minerals in a layered sample using time-resolved Raman spectroscopy and global analysis

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