scholarly journals Fluorescent Lead(IV) Sulfide Nanoparticles Synthesized by Idiomarina sp. Strain PR58-8 for Bioimaging Applications

2017 ◽  
Vol 83 (7) ◽  
Author(s):  
Pallavee Srivastava ◽  
Meenal Kowshik
Keyword(s):  
Near Infrared ◽  
Stokes Shift ◽  
Domain Size ◽  
Interplanar Distance ◽  
Metal Exposure ◽  
Visible Range ◽  
X Rays ◽  
Moderate Halophile ◽  
Content Type ◽  
Protein Thiols

ABSTRACT The fabrication of nanoparticles by microorganisms presents a “green” method for generating biocompatible nanomaterials. We discovered the intracellular biosynthesis of fluorescent lead(IV) sulfide nanoparticles by the moderate halophile, Idiomarina sp. strain PR58-8. The bacterium tolerated up to 8 mM Pb(NO3)2 during growth. Non-protein thiols dose-dependently increased in response to metal exposure, which suggests they are involved in the growth of PbS2 crystals and lead detoxification. Using X-ray diffraction, transmission electron microscopy (TEM), high-resolution TEM, and energy dispersive analysis of X-rays, the nanoparticles were characterized as spherical β-PbS2 nanoparticles (PbS2NPs) with a tetragonal crystal lattice, a crystallite domain size of 2.38 nm, and an interplanar distance of 0.318 nm. A narrow symmetric emission spectrum with a Gaussian distribution and an emission maximum at 386 nm was obtained when the particles were excited at 570 nm. The PbS2NPs exhibited a large Stokes' shift (8,362 cm−1) and a relatively high quantum yield (67%). These properties, along with fluorescence that was maintained in various microenvironments and their biocompatibility, make these nanoparticles excellent candidates for bioimaging. The particles were internalized by HeLa cells and evenly distributed within the cytoplasm, exhibiting their potential for in situ bioimaging applications. The “as-synthesized” lead(IV) sulfide nanoparticles may provide expanded opportunities for targeted bioimaging via modifying the surface of the particles. IMPORTANCE This article reports the intracellular synthesis of fluorescent lead(IV) sulfide nanoparticles (PbS2NPs) by a microorganism. All previous reports on the microbial synthesis of lead-based nanoparticles are on lead(II) sulfide that exhibits near-infrared fluorescence, requiring expensive instrumentation for bioimaging. Bioimaging using PbS2NPs can be achieved using routine epifluorescence microscopes, as it fluoresces in the visible range. The research on PbS2 nanoparticles to date is on their chemical synthesis employing toxic precursors, extreme pH, pressure, and temperature, resulting in cytotoxic products. In this context, the synthesis of PbS2 nanoparticles by Idiomarina sp. strain PR58-8, described in this work, occurs at ambient temperature and pressure and results in the generation of biocompatible nanoparticles with no hazardous by-products. The excellent fluorescence properties that these particles exhibit, as well as their abilities to easily penetrate the cells and evenly distribute within the cytoplasm, make them exceptional candidates for bioimaging applications. This study demonstrated the synthesis and fluorescence bioimaging application of microbially synthesized PbS2 nanoparticles.

A novel near-infrared fluorescent probe based on isophorone for the bioassay of endogenous cysteine

2021 ◽  
Author(s):  
Hong-Bo Liu ◽  
Hai Xu ◽  
Xin Guo ◽  
Jian Xiao ◽  
Zheng-Hong Cai ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Fluorescent Probe ◽  
Near Infrared ◽  
Stokes Shift ◽  
Rapid Identification ◽  
Large Stokes Shift

A near-infrared (NIR) fluorescent probe with a large Stokes shift (143 nm) for the rapid identification of Cys over Hcy and GSH in aqueous solution was developed.

scholarly journals Enhancing sub-bandgap external quantum efficiency by photomultiplication for narrowband organic near-infrared photodetectors

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jonas Kublitski ◽  
Axel Fischer ◽  
Shen Xing ◽  
Lukasz Baisinger ◽  
Eva Bittrich ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Near Infrared ◽  
Optical Cavity ◽  
Hole Injection ◽  
Visible Range ◽  
Absorption Region ◽  
Electromagnetic Signals ◽  
Organic Photodetectors

AbstractDetection of electromagnetic signals for applications such as health, product quality monitoring or astronomy requires highly responsive and wavelength selective devices. Photomultiplication-type organic photodetectors have been shown to achieve high quantum efficiencies mainly in the visible range. Much less research has been focused on realizing near-infrared narrowband devices. Here, we demonstrate fully vacuum-processed narrow- and broadband photomultiplication-type organic photodetectors. Devices are based on enhanced hole injection leading to a maximum external quantum efficiency of almost 2000% at −10 V for the broadband device. The photomultiplicative effect is also observed in the charge-transfer state absorption region. By making use of an optical cavity device architecture, we enhance the charge-transfer response and demonstrate a wavelength tunable narrowband photomultiplication-type organic photodetector with external quantum efficiencies superior to those of pin-devices. The presented concept can further improve the performance of photodetectors based on the absorption of charge-transfer states, which were so far limited by the low external quantum efficiency provided by these devices.

Use of an intracranial near-infrared probe for localization during stereotactic surgery for movement disorders

2000 ◽  
Vol 93 (3) ◽  
pp. 498-505 ◽  
Author(s):  
Cole A. Giller ◽  
Maureen Johns ◽  
Hanli Liu
Keyword(s):  
White Matter ◽  
Gray Matter ◽  
Movement Disorders ◽  
Near Infrared ◽  
Subcortical White Matter ◽  
Stereotactic Surgery ◽  
Resected Specimen ◽  
Subcortical Structures ◽  
Content Type ◽  
Fine Print

✓ Localization of targets during stereotactic surgery is frequently accomplished by identification of the boundaries between the gray matter of various nuclei and the surrounding white matter. The authors describe an intracranial probe developed for this purpose, which uses near-infrared (NIR) light.The probe fits through standard stereotactic holders and emits light at its tip. The scattered light is detected and analyzed by a spectrometer, with the slope of the trailing portion of the reflectance curve used as the measurement value.Near-infrared readings were obtained during 27 neurosurgical procedures. The first three operations were temporal lobectomies, with values obtained from tracks in the resected specimen and resection bed. In the next five procedures, the probe was inserted stereotactically to a depth of 1 to 2 cm with measurements obtained every 1 mm. The probe was then used in 19 stereotactic procedures for movement disorders, obtaining measurements every 0.5 to 1 mm to target depths of 6 to 8 cm to interrogate subcortical structures. The NIR signals were correlated to distances beneath the cortical surface measured on postoperative computerized tomography or magnetic resonance imaging by using angle correction and three-dimensional reconstruction techniques.The NIR values for white and gray matter obtained during the lobectomies were significantly different (white matter 2.5 ± 0.37, gray matter 0.82 ± 0.23 mean ± standard deviation). The NIR values from the superficial stereotactic tracks showed initial low values corresponding to cortical gray matter and high values corresponding to subcortical white matter.There was good correlation between the NIR signals and postoperative imaging in the 19 stereotactic cases. Dips due to adjacent sulci, a plateau of high signal due to subcortical white matter, a dip in the NIR signal during passage through the ventricle, dips due to the caudate nucleus, and peaks due to the white matter capsule between ventricle and thalamus were constant features. The putamen—capsule boundary and the lamina externa and interna of the globus pallidus could be distinguished in three cases. Elevated signals corresponding to the thalamic floor were seen in 10 cases. Nuances such as prior lesions and nonspecific white matter changes were also detected. There was no incidence of morbidity associated with use of the probe. Data acquisition was straightforward and the equipment required for the studies was inexpensive.The NIR probe described in this article seems to be able to detect gray—white matter boundaries around and within subcortical structures commonly encountered in stereotactic functional neurosurgery. This simple, inexpensive method deserves further study to establish its efficacy for stereotactic localization.

pnCCD for photon detection from near-infrared to X-rays

2006 ◽  
Vol 565 (1) ◽  
pp. 251-257 ◽  
Author(s):  
Norbert Meidinger ◽  
Robert Andritschke ◽  
Robert Hartmann ◽  
Sven Herrmann ◽  
Peter Holl ◽  
...  
Keyword(s):  
Near Infrared ◽  
X Rays ◽  
Photon Detection

Near Infrared Photothermoelectric Effect in Transparent AZO/ITO/Ag/ITO Thin Films

2021 ◽  
Author(s):  
Catarina Bianchi ◽  
Ana Marques ◽  
Rui Silva ◽  
Tomas Calmeiro ◽  
Isabel Ferreira
Keyword(s):  
Indium Tin Oxide ◽  
Near Infrared ◽  
Thermal Control ◽  
High Energy ◽  
Visible Range ◽  
Azo Thin Film ◽  
Ito Thin Films ◽  
Aluminum Doped Zinc Oxide ◽  
Temperature Constant ◽  
20 Nm

Abstract A new concept of oxide-metal-oxide structures that combine photothermoelectric effect with high reflectance (~80%) at wavelengths in the infrared (> 1100 nm) and high transmittance in the visible range is reported here. This was observed in optimized ITO/Ag/ITO structure, 20 nm of Siver (Ag) and 40 nm of Indium Tin Oxide (ITO), deposited on Aluminum doped Zinc Oxide (AZO) thin film. These layers show high energy saving efficiency by keeping the temperature constant inside a glazed compartment under solar radiation, but additionally they also show a photothermoelectric effect. Under uniform heating of the sample a thermoelectric effect is observed (S = 40 μV/K), but when irradiated, a potential proportional to the intensity of the radiation is also observed. Therefore, in addition to thermal control in windows, these low emission coatings can be applied as transparent photothermoelectric devices.

Evaluation of extracranial—intracranial arterial bypass function by using near-infrared spectroscopy

2003 ◽  
Vol 99 (2) ◽  
pp. 304-310 ◽  
Author(s):  
Yoshihiro Murata ◽  
Yoichi Katayama ◽  
Kaoru Sakatani ◽  
Chikashi Fukaya ◽  
Tsuneo Kano
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Sensorimotor Cortex ◽  
Bypass Surgery ◽  
Near Infrared ◽  
Cutoff Value ◽  
Content Type ◽  
Arterial Bypass ◽  
Group Iii ◽  
Fine Print

Object. It has been reported that extracranial—intracranial (EC—IC) arterial bypass surgery can be useful in preventing stroke in patients with hemodynamic compromise. Little is yet known, however, regarding the extent to which the bypass contributes to maintaining adequate cerebral blood oxygenation (CBO) and its temporal changes following surgery. The authors evaluated bypass function repeatedly by using near-infrared spectroscopy (NIRS) after surgery. Methods. The authors investigated 30 patients who had undergone EC—IC bypass surgery. Single-photon emission computerized tomography revealed a decrease in regional cerebral blood flow (rCBF) and a lowered rCBF response to acetazolamide. Changes in CBO were evaluated in the sensorimotor cortex during compression of the anastomosed superficial temporal artery (STA). When decreases in oxyhemoglobin (HbO2) and total hemoglobin (Hb) concentrations were observed, the bypass was considered to have maintained CBO in the sensorimotor cortex given that decreases in HbO2 and total Hb indicate cerebral ischemic changes. The bypass maintained CBO immediately after surgery in 36.7% of patients (Group I, 11 patients) and at some time after surgery, mostly within 1 year, in 43.3% of patients (Group II, 13 patients); however, it did not maintain it throughout the follow-up period in 20% of patients (Group III, six patients). Note that the preoperative rCBF in patients in Groups I and II was lower than that in patients in Group III (p < 0.004). In fact, the preoperative rCBF predicted whether a bypass would maintain CBO at a cutoff value of 24.5 to 25 ml/100 g/min. Among Groups I and II, 18 patients demonstrated an increase in deoxyhemoglobin during STA compression. The preoperative rCBF in these cases was lower than that in the six remaining patients (p < 0.006). Note that the preoperative rCBF predicted the postoperative deoxyhemoglobin response at a cutoff value of 22.2 to 24 ml/100 g/min. Conclusions. The EC—IC bypass surgery can maintain CBO immediately after surgery or gradually within 1 year when the preoperative rCBF is below 24.5 to 25 ml/100 g/min. Furthermore, bypass flow plays a critical role in maintaining an adequate CBO when preoperative rCBF is below 22.2 to 24 ml/100 g/min.

scholarly journals Combination of Zinc Oxide and Antimony Doped Tin Oxide Nanocoatings for Glazing Application

Coatings ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 248 ◽  
Author(s):  
Benjamin Schumm ◽  
Thomas Abendroth ◽  
Saleh A. Alajlan ◽  
Ahmed M. Almogbel ◽  
Holger Althues ◽  
...  
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Optical Properties ◽  
Tin Oxide ◽  
Near Infrared ◽  
Glass Production ◽  
Float Glass ◽  
Building Envelope ◽  
Visible Range ◽  
Production Processes

Multilayered nanocoatings allow outstanding properties with broad potential for glazing applications. Here, we report on the development of a multilayer nanocoating for zinc oxide (ZnO) and antimony doped tin oxide (ATO). The combination of ZnO and ATO thin films with their promising optical properties is a cost-efficient alternative for the production of energy-efficient glazing. It is an effective modification of the building envelope to reduce current high domestic demand of electrical power for air conditioning, especially in hot climates like Saudi Arabia. In this paper, we report the development of a nanocoating based on the combination of ZnO and ATO. Principle material and film investigations were carried out on lab-scale by dip coating with chemical solution deposition (CSD), while with regard to production processes, chemical vapor deposition (CVD) processes were evaluated in a second stage of the film development. It was found that with both processes, high-quality thin films and multilayer coatings with outstanding optical properties can be prepared. While keeping the optical transmission in the visible range at around 80%, only 10% of the NIR (near infrared) and below 1% of UV (ultraviolet) light passes these coatings. However, in contrast to CSD, the CVD process allows a free combination of the multilayer film sequence, which is of high relevance for production processes. Furthermore, it can be potentially integrated in float glass production lines.

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