scholarly journals Exfoliation and Optical Properties of Near-Infrared Fluorescent Silicate Nanosheets

2021 ◽  
Author(s):  
Gabriele Selvaggio ◽  
Milan Weitzel ◽  
Nazar Oleksiievets ◽  
Tabea A. Oswald ◽  
Robert Nißler ◽  
...  
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Photophysical Properties ◽  
Fluorescence Lifetime Imaging ◽  
Fluorescence Lifetimes ◽  
Macroscopic Scale ◽  
Remote Imaging ◽  
Lifetime Imaging ◽  
Tissue Phantoms ◽  
Nir Fluorescence

<div><div><div><p>The silicates Egyptian Blue (CaCuSi4O10, EB), Han Blue (BaCuSi4O10, HB) and Han Purple (BaCuSi2O6, HP) emit in bulk bright and stable fluorescence in the near-infrared (NIR), which is of high interest for (bio)photonics due to minimal scattering, absorption and phototoxicity in this spectral range. So far the optical properties of nanosheets (NS) of these silicates are poorly understood. Here, we exfoliate them into nanosheets and report their physicochemical properties. The approach uses ball milling followed by tip sonication and centrifugation steps to exfoliate the silicates into NS with a lateral size ≈ 16-27 nm and thickness ≈ 1-4 nm. They emit at ≈ 927 nm (EB-NS), 953 nm (HB-NS) and 924 nm (HP-NS) and single NS can be resolved in the NIR. Fluorescence lifetimes decrease from ≈ 30-100 μs (bulk) to 17 μs (EB- NS), 8 μs (HB-NS) and 7 μs (HP-NS). NS of different composition/size can be imaged by fluorescence lifetime imaging, which enables lifetime-encoded multicolor imaging both on the microscopic and the macroscopic scale. Finally, remote imaging through tissue phantoms reveals the potential for bioimaging. In summary, we report a procedure to gain NIR fluorescent silicate nanosheets, characterize their photophysical properties and show their potential for NIR photonics.</p></div></div></div>

scholarly journals Exfoliation and Optical Properties of Near-Infrared Fluorescent Silicate Nanosheets

2021 ◽  
Author(s):  
Gabriele Selvaggio ◽  
Milan Weitzel ◽  
Nazar Oleksiievets ◽  
Tabea A. Oswald ◽  
Robert Nißler ◽  
...  
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Photophysical Properties ◽  
Fluorescence Lifetime Imaging ◽  
Fluorescence Lifetimes ◽  
Macroscopic Scale ◽  
Remote Imaging ◽  
Lifetime Imaging ◽  
Tissue Phantoms ◽  
Nir Fluorescence

<div><div><div><p>The silicates Egyptian Blue (CaCuSi4O10, EB), Han Blue (BaCuSi4O10, HB) and Han Purple (BaCuSi2O6, HP) emit in bulk bright and stable fluorescence in the near-infrared (NIR), which is of high interest for (bio)photonics due to minimal scattering, absorption and phototoxicity in this spectral range. So far the optical properties of nanosheets (NS) of these silicates are poorly understood. Here, we exfoliate them into nanosheets and report their physicochemical properties. The approach uses ball milling followed by tip sonication and centrifugation steps to exfoliate the silicates into NS with a lateral size ≈ 16-27 nm and thickness ≈ 1-4 nm. They emit at ≈ 927 nm (EB-NS), 953 nm (HB-NS) and 924 nm (HP-NS) and single NS can be resolved in the NIR. Fluorescence lifetimes decrease from ≈ 30-100 μs (bulk) to 17 μs (EB- NS), 8 μs (HB-NS) and 7 μs (HP-NS). NS of different composition/size can be imaged by fluorescence lifetime imaging, which enables lifetime-encoded multicolor imaging both on the microscopic and the macroscopic scale. Finally, remote imaging through tissue phantoms reveals the potential for bioimaging. In summary, we report a procedure to gain NIR fluorescent silicate nanosheets, characterize their photophysical properties and show their potential for NIR photonics.</p></div></div></div>

scholarly journals Photophysical Properties and Fluorescence Lifetime Imaging of Exfoliated Near-Infrared Fluorescent Silicate Nanosheets

2021 ◽  
Author(s):  
Gabriele Selvaggio ◽  
Milan Weitzel ◽  
Nazar Oleksiievets ◽  
Tabea Anne Oswald ◽  
Robert Nißler ◽  
...  
Keyword(s):  
Fluorescence Lifetime ◽  
Near Infrared ◽  
Bulk Material ◽  
Photophysical Properties ◽  
Layered Silicates ◽  
Fluorescence Lifetime Imaging ◽  
Egyptian Blue ◽  
Lifetime Imaging

The layered silicates Egyptian Blue (CaCuSi4O10, EB), Han Blue (BaCuSi4O10, HB) and Han Purple (BaCuSi2O6, HP) emit as bulk material bright and stable fluorescence in the near-infrared (NIR), which is...

scholarly journals In vitro and in vivo NIR Fluorescence Lifetime Imaging with a time-gated SPAD camera

2021 ◽  
Author(s):  
Jason T. Smith ◽  
Alena Rudkouskaya ◽  
Shan Gao ◽  
Juhi M. Gupta ◽  
Arin Ulku ◽  
...  
Keyword(s):  
Fluorescence Lifetime ◽  
Near Infrared ◽  
Single Photon ◽  
In Vivo Studies ◽  
Fluorescence Lifetime Imaging ◽  
Iccd Camera ◽  
Lifetime Imaging ◽  
Nir Fluorescence

Near-infrared (NIR) fluorescence lifetime imaging (FLI) provides a unique contrast mechanism to monitor biological parameters and molecular events in vivo. Single-photon avalanche photodiode (SPAD) cameras have been recently demonstrated in FLI microscopy (FLIM) applications, but their suitability for in vivo macroscopic FLI (MFLI) in deep tissues remains to be demonstrated. Herein, we report in vivo NIR MFLI measurement with SwissSPAD2, a large time-gated SPAD camera. We first benchmark its performance in well-controlled in vitro experiments, ranging from monitoring environmental effects on fluorescence lifetime, to quantifying Förster Resonant Energy Transfer (FRET) between dyes. Next, we use it for in vivo studies of target-drug engagement in live and intact tumor xenografts using FRET. Information obtained with SwissSPAD2 was successfully compared to that obtained with a gated-ICCD camera, using two different approaches. Our results demonstrate that SPAD cameras offer a powerful technology for in vivo preclinical applications in the NIR window.

scholarly journals Multi-layered tissue head phantoms for noninvasive optical diagnostics

2015 ◽  
Vol 08 (03) ◽  
pp. 1541005 ◽  
Author(s):  
M. S. Wróbel ◽  
A. P. Popov ◽  
A. V. Bykov ◽  
M. Kinnunen ◽  
M. Jędrzejewska-Szczerska ◽  
...  
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Optical Measurement ◽  
Human Head ◽  
Medical Diagnostics ◽  
Optical Parameters ◽  
Measurement Systems ◽  
Tissue Phantoms ◽  
Optical And Mechanical Properties

Extensive research in the area of optical sensing for medical diagnostics requires development of tissue phantoms with optical properties similar to those of living human tissues. Development and improvement of in vivo optical measurement systems requires the use of stable tissue phantoms with known characteristics, which are mainly used for calibration of such systems and testing their performance over time. Optical and mechanical properties of phantoms depend on their purpose. Nevertheless, they must accurately simulate specific tissues they are supposed to mimic. Many tissues and organs including head possess a multi-layered structure, with specific optical properties of each layer. However, such a structure is not always addressed in the present-day phantoms. In this paper, we focus on the development of a plain-parallel multi-layered phantom with optical properties (reduced scattering coefficient [Formula: see text] and absorption coefficient μa) corresponding to the human head layers, such as skin, skull, and gray and white matter of the brain tissue. The phantom is intended for use in noninvasive diffuse near-infrared spectroscopy (NIRS) of human brain. Optical parameters of the fabricated phantoms are reconstructed using spectrophotometry and inverse adding-doubling calculation method. The results show that polyvinyl chloride-plastisol (PVCP) and zinc oxide ( ZnO ) nanoparticles are suitable materials for fabrication of tissue mimicking phantoms with controlled scattering properties. Good matching was found between optical properties of phantoms and the corresponding values found in the literature.

scholarly journals Fluorescence lifetime imaging of upper gastrointestinal pH in vivo with a lanthanide based near-infrared τ probe

2019 ◽  
Vol 10 (15) ◽  
pp. 4227-4235 ◽  
Author(s):  
Yingying Ning ◽  
Shengming Cheng ◽  
Jing-Xiang Wang ◽  
Yi-Wei Liu ◽  
Wei Feng ◽  
...  
Keyword(s):  
Fluorescence Lifetime ◽  
Near Infrared ◽  
Lanthanide Complex ◽  
Fluorescence Lifetime Imaging ◽  
Ph Responsive ◽  
Gastrointestinal Ph ◽  
Lifetime Imaging ◽  
Upper Gastrointestinal

Lanthanide complex was successfully applied in the design of pH-responsive NIR τ probe for quantitative in vivo imaging.

Fluorescence lifetime imaging with near-infrared dyes

2015 ◽  
Vol 4 (1) ◽  
Author(s):  
Wolfgang Becker ◽  
Vladislav Shcheslavskiy
Keyword(s):  
Fluorescence Lifetime ◽  
Laser Scanning ◽  
Near Infrared ◽  
Single Photon ◽  
Optical Tomography ◽  
Small Animal Imaging ◽  
Supplementary Information ◽  
Fluorescence Lifetime Imaging ◽  
Lifetime Imaging ◽  
Nir Dyes

AbstractNear-infrared (NIR) dyes are used as fluorescence markers in small animal imaging and in diffuse optical tomography. In these applications it is important to know whether the dyes bind to proteins or to other tissue constituents, and whether their fluorescence lifetimes depend on the targets they bind to. Unfortunately, neither the optical beam paths nor the detectors of commonly used in confocal and multiphoton laser scanning microscopes (LSMs) directly allow for excitation and detection of NIR fluorescence. This paper presents three ways of adapting existing LSMs with time-correlated single photon counting (TCSPC) fluorescence lifetime imaging (FLIM) systems for NIR FLIM: 1) confocal systems with wideband beamsplitters and diode laser excitation, 2) confocal systems with wideband beamsplitters and one-photon excitation by titanium-sapphire lasers, and 3) two-photon systems with optical parametric oscillator (OPO) excitation and non-descanned detection. A number of NIR dyes are tested in biological tissue. All of them show clear lifetime changes depending on the tissue structures they are bound to. We therefore believe that NIR FLIM can deliver supplementary information about the tissue composition and on local biochemical parameters.

scholarly journals Fast fit-free analysis of fluorescence lifetime imaging via deep learning

2019 ◽  
Vol 116 (48) ◽  
pp. 24019-24030 ◽  
Author(s):  
Jason T. Smith ◽  
Ruoyang Yao ◽  
Nattawut Sinsuebphon ◽  
Alena Rudkouskaya ◽  
Nathan Un ◽  
...  
Keyword(s):  
Deep Learning ◽  
Fluorescence Lifetime ◽  
Near Infrared ◽  
Quantitative Information ◽  
Fluorescence Lifetime Imaging ◽  
Complex Data ◽  
Lifetime Imaging ◽  
Spatially Resolved ◽  
Lifetime Studies ◽  
Net Framework

Fluorescence lifetime imaging (FLI) provides unique quantitative information in biomedical and molecular biology studies but relies on complex data-fitting techniques to derive the quantities of interest. Herein, we propose a fit-free approach in FLI image formation that is based on deep learning (DL) to quantify fluorescence decays simultaneously over a whole image and at fast speeds. We report on a deep neural network (DNN) architecture, named fluorescence lifetime imaging network (FLI-Net) that is designed and trained for different classes of experiments, including visible FLI and near-infrared (NIR) FLI microscopy (FLIM) and NIR gated macroscopy FLI (MFLI). FLI-Net outputs quantitatively the spatially resolved lifetime-based parameters that are typically employed in the field. We validate the utility of the FLI-Net framework by performing quantitative microscopic and preclinical lifetime-based studies across the visible and NIR spectra, as well as across the 2 main data acquisition technologies. These results demonstrate that FLI-Net is well suited to accurately quantify complex fluorescence lifetimes in cells and, in real time, in intact animals without any parameter settings. Hence, FLI-Net paves the way to reproducible and quantitative lifetime studies at unprecedented speeds, for improved dissemination and impact of FLI in many important biomedical applications ranging from fundamental discoveries in molecular and cellular biology to clinical translation.

scholarly journals In Vivo Dendritic Cell Tracking Using Fluorescence Lifetime Imaging and Near-Infrared-Emissive Polymersomes

2009 ◽  
Vol 11 (3) ◽  
pp. 167-177 ◽  
Author(s):  
Natalie A. Christian ◽  
Fabian Benencia ◽  
Michael C. Milone ◽  
Guizhi Li ◽  
Paul R. Frail ◽  
...  
Keyword(s):  
Dendritic Cell ◽  
Fluorescence Lifetime ◽  
Cell Tracking ◽  
Near Infrared ◽  
Fluorescence Lifetime Imaging ◽  
Lifetime Imaging
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