Label-Free Spatial Analysis of Free and Enzyme-Bound NAD(P)H in the Presence of High Concentrations of Melanin

Herbrich, Sebastian; Gehder, Matthias; Krull, Rainer; Gericke, Karl‐Heinz

doi:10.1007/s10895-011-0965-5

Cited by 12 publications

(14 citation statements)

References 22 publications

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“…Another strategy uses offline techniques to measure and characterize the general autofluorescence signature of selected bioaerosol types. In some studies fluorescence microscopy is used to understand general fluorescence patterns and fluorophore locations in bioaerosol proxies (e.g., Roshchina et al, 2004;Herbrich et al, 2012). Other studies have applied fluorescence spectroscopy to understand characteristic emission signatures (e.g., O'Connor et al, 2011).…”

Section: Autofluorescence In Bioaerosol Detectionmentioning

confidence: 99%

Autofluorescence of atmospheric bioaerosols: spectral fingerprints and taxonomic trends of pollen

et al. 2013

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Primary biological aerosol particles (PBAP) are important factors in atmospheric cycling, climate, and public health. Pollen is a major fraction of PBAP and is receiving increasing attention due to its high allergenic potential and the associated impacts on personal life quality and economy. Recently, autofluorescence-based techniques have proven to be valuable tools for real time, in situ quantification and classification of PBAP. First studies suggest that the autofluorescence of pollen may be sufficiently selective to be utilized for an automated and real-time monitoring of pollen in ambient air. However, the degree of selectivity autofluorescence can provide is still in question and actively debated.This study addresses the origin, properties, and selectivity of autofluorescence from natural pollen by fluorescence microscopy and spectroscopy measurements along with a systematic synthesis of related literature. We show that dry pollen reveals characteristic and reproducible autofluorescence signatures which are shaped by cell wall associated fluorophores, such as phenolic compounds and carotenoid pigments. In addition, fluorescence signals from proteins and chlorophyll a were observed in some species. The abundance and intensity of the individual fluorescence signals show certain taxonomic trends and allow systematic differentiation from bacteria and fungal spores due to the lack of proteins on the grain surface. Principal component analysis was used to explore the discrimination potential of pollen autofluorescence, in combination with size and shape, revealing a differentiation of pollen on family level. Our results help explore the levels of selectivity that autofluorescence-based techniques can provide to PBAP analysis and will support the development and application of autofluorescence-based detectors for monitoring of allergenic pollen in the atmosphere.www.atmos-meas-tech.net/6/3369/2013/ Atmos. Meas. Tech., 6, 3369-3392, 2013

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Section: Autofluorescence In Bioaerosol Detectionmentioning

confidence: 99%

Autofluorescence of atmospheric bioaerosols: spectral fingerprints and taxonomic trends of pollen

et al. 2013

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“…The fluorescence lifetime of most biofluorophores, serving as targets for bioaerosol detection, are usually below 10 ns (e.g., Chorvat & Chorvatova, 2009;Herbrich, et al, 2012;O'Connor et al, 2014;Richards-Kortum & Sevick-Muraca, 1996). However, by choosing xenon lamps as excitation source, recording relevant fluorescence lifetimes in this ns range is hampered by the relatively long decay time of the xenon lamp excitation pulse (~1.5 µs).…”

Section: Spectrally Resolved Fluorescence Detectionmentioning

confidence: 99%

Spectral Intensity Bioaerosol Sensor (SIBS): A new Instrument for Spectrally Resolved Fluorescence Detection of Single Particles in Real-Time

Könemann¹,

Savage²,

Klimach³

et al. 2018

Preprint

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Abstract. Primary biological aerosol particles (PBAP) in the atmosphere are highly relevant for the Earth system, climate, and public health. The analysis of PBAP, however, remains challenging due to their high diversity and large spatiotemporal variability. For real-time PBAP analysis, light-induced fluorescence (LIF) instruments have been developed and widely used in laboratory and ambient studies. The interpretation of fluorescence data from these instruments, however, is often limited by a lack of spectroscopic information. This study introduces a new instrument – the Spectral Intensity Bioaerosol Sensor (SIBS) – that resolves fluorescence spectra for single particles and, thus, promises to expand the scope of fluorescent PBAP quantification and classification. The SIBS shares key design components with the latest versions of the Wideband Integrated Bioaerosol Sensor (WIBS) and the findings presented here are also relevant for the widely deployed WIBS-4A and WIBS-NEO as well as other LIF instruments. The key features of the SIBS and findings of this study can be summarized as follows: – Particle sizing yields reproducible linear responses for particles in the range of 300 nm to 20 µm. The lower sizing limit is significantly smaller than for earlier commercial LIF instruments (e.g., WIBS-4A and the Ultraviolet Aerodynamic Particle Sizer (UV-APS)), expanding the analytical scope into the accumulation mode size range. – Fluorescence spectra are recorded for two excitation wavelengths (λex = 285 and 370 nm) and a wide range of emission wavelengths (λmean = 302–721 nm) with a resolution of 16 detection channels, which is higher than for most other commercially available LIF bioaerosol sensors. – Fluorescence spectra obtained for 16 reference compounds confirm that the SIBS provides sufficient spectral resolution to distinguish major modes of molecular fluorescence. For example, the SIBS resolves the spectral difference between bacteriochlorophyll and chlorophyll a/b. – A spectral correction of the instrument-specific detector response is essential to use the full fluorescence emission range. – Asymmetry factor (AF) data were assessed and were found to provide only limited analytical information. – In test measurements with ambient air, the SIBS worked reliably and yielded characteristically different spectra for single particles in the coarse mode with an overall fluorescent particle fraction of ~ 4 % (3σ threshold), which is consistent with earlier studies in comparable environments.

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“…The latest WIBS model is currently the WIBS-NEO, whose design is based on a WIBS-4A but with an extended particle size detection range between ∼ 500 nm and 30 µm (nominal). Both UV-APS and WIBS models have been examined in a variety of laboratory validations (e.g., Agranovski et al, 2003Agranovski et al, , 2004Brosseau et al, 2000;Healy et al, 2012;Hernandez et al, 2016;Kanaani et al, 2007;O'Connor et al, 2013;Saari et al, 2013Saari et al, , 2014Savage et al, 2017;Toprak and Schnaiter, 2013) and have been deployed to investigate both indoor and outdoor atmospheric aerosol via longer-term measurements (e.g., Bhangar et al, 2014;Calvo et al, 2018;Crawford et al, 2016;Fernández-Rodríguez et al, 2018;Foot et al, 2008;Gabey et al, 2010Gabey et al, , 2013Gosselin et al, 2016;Healy et al, 2014;Huffman et al, 2010Huffman et al, , 2012Ma et al, 2019;Perring et al, 2015;Schumacher et al, 2013;Twohy et al, 2016;Ziemba et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…For example, the quantification of PBAPs by LIF instruments is hindered by the fact that some biological materials reveal weak fluorescence characteristics that do not rise above detection thresholds (Huffman et al, 2012). In addition to this complication, the detection threshold is not a universally defined parameter and varies for each channel between different units of the same type of instrument (e.g., Hernandez et al, 2016;Savage et al, 2017). Furthermore, the unambiguous spectroscopic characterization of bioparticles is fundamentally challenging because fluorescence spectra of even individual molecules in condensed matter are relatively broad due to radiative decay pathways of excited electrons.…”

Section: Introductionmentioning

confidence: 99%

Spectral Intensity Bioaerosol Sensor (SIBS): an instrument for spectrally resolved fluorescence detection of single particles in real time

et al. 2019

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Abstract. Primary biological aerosol particles (PBAPs) in the atmosphere are highly relevant for the Earth system, climate, and public health. The analysis of PBAPs, however, remains challenging due to their high diversity and large spatiotemporal variability. For real-time PBAP analysis, light-induced fluorescence (LIF) instruments have been developed and widely used in laboratory and ambient studies. The interpretation of fluorescence data from these instruments, however, is often limited by a lack of spectroscopic information. This study introduces an instrument – the Spectral Intensity Bioaerosol Sensor (SIBS; Droplet Measurement Technologies (DMT), Longmont, CO, USA) – that resolves fluorescence spectra for single particles and thus promises to expand the scope of fluorescent PBAP quantification and classification. The SIBS shares key design components with the latest versions of the Wideband Integrated Bioaerosol Sensor (WIBS) and the findings presented here are also relevant for the widely deployed WIBS-4A and WIBS-NEO as well as other LIF instruments. The key features of the SIBS and the findings of this study can be summarized as follows. Particle sizing yields reproducible linear responses for particles in the range of 300 nm to 20 µm. The lower sizing limit is significantly smaller than for earlier commercial LIF instruments (e.g., WIBS-4A and the Ultraviolet Aerodynamic Particle Sizer; UV-APS), expanding the analytical scope into the accumulation-mode size range. Fluorescence spectra are recorded for two excitation wavelengths (λex=285 and 370 nm) and a wide range of emission wavelengths (λmean=302–721 nm) with a resolution of 16 detection channels, which is higher than for most other commercially available LIF bioaerosol sensors. Fluorescence spectra obtained for 16 reference compounds confirm that the SIBS provides sufficient spectral resolution to distinguish major modes of molecular fluorescence. For example, the SIBS resolves the spectral difference between bacteriochlorophyll and chlorophyll a and b. A spectral correction of the instrument-specific detector response is essential to use the full fluorescence emission range. Asymmetry factor (AF) data were assessed and were found to provide only limited analytical information. In test measurements with ambient air, the SIBS worked reliably and yielded characteristically different spectra for single particles in the coarse mode with an overall fluorescent particle fraction of ∼4 % (3σ threshold), which is consistent with earlier studies in comparable environments.

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Label-Free Spatial Analysis of Free and Enzyme-Bound NAD(P)H in the Presence of High Concentrations of Melanin

Cited by 12 publications

References 22 publications

Autofluorescence of atmospheric bioaerosols: spectral fingerprints and taxonomic trends of pollen

Autofluorescence of atmospheric bioaerosols: spectral fingerprints and taxonomic trends of pollen

Spectral Intensity Bioaerosol Sensor (SIBS): A new Instrument for Spectrally Resolved Fluorescence Detection of Single Particles in Real-Time

Spectral Intensity Bioaerosol Sensor (SIBS): an instrument for spectrally resolved fluorescence detection of single particles in real time

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