Dr. Shweta V. Pawar Profile

Dr. Shweta V. Pawar

at Bar Ilan Univ

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Publications (4)

SPIE Journal Paper | 23 May 2023 Open Access

Imaging the rotational mobility of carbon dot-gold nanoparticle conjugates using frequency domain wide-field time-resolved fluorescence anisotropy

Gilad Yahav, Shweta Pawar, Yitzchak Weber, Bar Atuar, Hamootal Duadi, Dror Fixler

JBO, Vol. 28, Issue 05, 056001, (May 2023) https://doi.org/10.1117/12.10.1117/1.JBO.28.5.056001

KEYWORDS: Cadmium sulfide, Carbon, Gold, Fluorescence, Viscosity, Histograms, Fluorescence lifetime imaging, Biomedical optics, Biological imaging, Fluorescence imaging

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SignificanceWide-field measurements of time-resolved fluorescence anisotropy (TR-FA) provide pixel-by-pixel information about the rotational mobility of fluorophores, reflecting changes in the local microviscosity and other factors influencing the fluorophore’s diffusional motion. These features offer promising potential in many research fields, including cellular imaging and biochemical sensing, as demonstrated by previous works. Nevertheless, θ imaging is still rarely investigated in general and in carbon dots (CDs) in particular.AimTo extend existing frequency domain (FD) fluorescence lifetime (FLT) imaging microscopy (FLIM) to FD TR-FA imaging (TR-FAIM), which produces visual maps of the FLT and θ, together with the steady-state images of fluorescence intensity (FI) and FA (r).ApproachThe proof of concept of the combined FD FLIM/ FD TR-FAIM was validated on seven fluorescein solutions with increasing viscosities and was applied for comprehensive study of two types of CD-gold nano conjugates.ResultsThe FLT of fluorescein samples was found to decrease from 4.01 ± 0.01 to 3.56 ± 0.02 ns, whereas both r and θ were significantly increased from 0.053 ± 0.012 to 0.252 ± 0.003 and 0.15 ± 0.05 to 11.25 ± 1.87 ns, respectively. In addition, the attachment of gold to the two CDs resulted in an increase in the FI due to metal-enhanced fluorescence. Moreover, it resulted in an increase of r from 0.100 ± 0.011 to 0.150 ± 0.013 and θ from 0.98 ± 0.13 to 1.65 ± 0.20 ns for the first CDs and from 0.280 ± 0.008 to 0.310 ± 0.004 and 5.55 ± 1.08 to 7.95 ± 0.97 ns for the second CDs. These trends are due to the size increase of the CDs-gold compared to CDs alone. The FLT presented relatively modest changes in CDs.ConclusionsThrough the combined FD FLIM/ FD TR-FAIM, a large variety of information can be probed (FI, FLT, r, and θ). Nevertheless, θ was the most beneficial, either by probing the spatial changes in viscosity or by evident variations in the peak and full width half maximum.

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Proceedings Article | 17 March 2023 Poster + Paper

Imaging the rotational mobility of a fluorophore by frequency domain time-resolved fluorescence anisotropy

Gilad Yahav, Shweta Pawar, Yitzchak Weber, Bar Atuar, Hamootal Duadi, Dror Fixler

Proceedings Volume 12394, 1239409 (2023) https://doi.org/10.1117/12.2648025

KEYWORDS: Fluorescence imaging, Biological imaging, Viscosity, Fluorophores, Fluorescence lifetime imaging, Beam splitters, Biological samples, Time resolved spectroscopy, Fluorescence, Anisotropy

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Proceedings Article | 17 March 2023 Poster + Paper

Bioimaging, pH sensing, and fluorescence lifetime imaging microscopy using polyethyleneimine coated carbon dots and gold nanoparticles

Shweta Pawar, Hamootal Duadi, Dror Fixler

Proceedings Volume 12394, 1239408 (2023) https://doi.org/10.1117/12.2648414

KEYWORDS: Cadmium sulfide, Fluorescence, Carbon dots, Gold nanoparticles, Fluorescence lifetime imaging, Nanomaterials, Gold, Fluorescence intensity, Microscopy, Metals

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Proceedings Article | 3 March 2022 Poster + Paper

Nano logic gates based on gold nanoparticles- carbon dots hybrid and its FLIM imaging

Shweta Pawar, Hamootal Duadi, Yafit Fleger, Dror Fixler

Proceedings Volume 11976, 1197607 (2022) https://doi.org/10.1117/12.2607925

KEYWORDS: Cadmium sulfide, Logic devices, Logic, Luminescence, Fluorescence lifetime imaging, Gold, Carbon, Nanoparticles, Nanostructures, Nanotechnology

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