Rapid FRET-based homogeneous immunoassay of procalcitonin using matched carbon dots labels

2021 ◽  
Author(s):  
Bo Liu ◽  
Kun Yang ◽  
Siyu Lu ◽  
Junjie Cai ◽  
Fan Li ◽  
...  
Keyword(s):  
Carbon Dots ◽  
Fluorescence Emission ◽  
Intensity Variation ◽  
Homogeneous System ◽  
Rabbit Serum ◽  
Buffer Solution ◽  
Novel Method ◽  
External Light Source ◽  
Source Excitation ◽  
Weak Luminescence

Abstract A novel method for the detection of procalcitonin in a homogeneous system by matched carbon dots (CDs) labeled immunoprobes was proposed based on the principle of FRET and double antibody sandwich method. Blue-emitting carbon dots with a strong fluorescence emission range of 400-550nm and red-emitting carbon dots with the best excitation range of 410-550nm were prepared before they reacted with procalcitonin protoclone antibody pairs to form immunoprobes. According to the principles of FRET, blue-emitting carbon dots were selected as the energy donor and red-emitting carbon dots as the energy receptor. The external light source excitation (310nm) could only cause weak luminescence of CDs. However, once procalcitonin was added, procalcitonin and antibodies would be combined with each other quickly (≤ 20 min). Here, blue-emitting carbon dots acquired energy could be transferred to red-emitting carbon dots efficiently, causing the emitted fluorescence enhancement of red-emitting carbon dots. The fluorescence detection results in PBS buffer solution and diluted rabbit blood serum showed that the fluorescence intensity variation was linear with the concentration of procalcitonin. There was a good linear relationship between F/F0 and procalcitonin concentrations in PBS buffer solution that ranged from 0 to 100ng/ml, and the linear equation was F/F0 = 0.004 * Cpct + 0.98359. Detection in the diluted rabbit serum led to the results that were linear in two concentration ranges, including 0-40ng/ml and 40-100ng/ml, and the detection limit based on 3σ/K was 0.52ng/ml. It’s likely that this matched CDs labeled immunoprobes system can provide a new mode for rapid homogeneous detection of disease markers.

Green and Simple Synthesis of Photoluminescence-Tunable Carbon Dots for Sensing and Cell Imaging Applications

2021 ◽  
Vol 21 (12) ◽  
pp. 6101-6110
Author(s):  
Dong Sun ◽  
Shu-Jun Li ◽  
Chun-Feng Wang ◽  
Tian-Tian Liu ◽  
Guang-Yue Bai ◽  
...  
Keyword(s):  
Boric Acid ◽  
Carbon Dots ◽  
Luminescence Property ◽  
Cell Imaging ◽  
Fluorescence Emission ◽  
Fluorescent Imaging ◽  
Simple Synthesis ◽  
Low Toxicity ◽  
Doped Carbon Dots ◽  
Co Doped

Innovative nitrogen and boron co-doped carbon dots are hydrothermally produced using fructose, urea, and boric acid as precursors. The synthesized carbon dots possess a uniform morphology, and exhibit excellent fluorescence stability, tunable luminescence property, strong resistance to photobleaching, low-toxicity, and excellent biocompatibility. It is also found more dopant urea is conducive to the formation of the carbon dots with more B–N bonds, and shorter wavelength of fluorescence emission. Meanwhile, the synthesized carbon dots are well utilized as a photoluminescent probe for facile Hg2+ determination and fluorescent imaging reagent in cells.

scholarly journals Using Scuba for In Situ Determination of Chlorophyll Distributions in Corals by Underwater Near Infrared Fluorescence Imaging

2020 ◽  
Vol 8 (1) ◽  
pp. 53
Author(s):  
Thomas Oh ◽  
Jittiwat Sermsripong ◽  
Barry W. Hicks
Keyword(s):  
Fluorescence Imaging ◽  
Large Scale ◽  
Near Infrared ◽  
Fluorescent Proteins ◽  
Fluorescence Emission ◽  
Florida Keys ◽  
Nir Fluorescence ◽  
Novel Method ◽  
Near Infrared Fluorescence Imaging

Studies reporting quantitation and imaging of chlorophyll in corals using visible fluorescent emission in the red near 680 nm can suffer from competing emission from other red-emitting pigments. Here, we report a novel method of selectively imaging chlorophyll distributions in coral in situ using only the near infrared (NIR) fluorescence emission from chlorophyll. Commercially available equipment was assembled that allowed the sequential imaging of visible, visible-fluorescent, and NIR-fluorescent pigments on the same corals. The relative distributions of chlorophyll and fluorescent proteins (GFPs) were examined in numerous corals in the Caribbean Sea, the Egyptian Red Sea, the Indonesian Dampier Strait, and the Florida Keys. Below 2 m depth, solar induced NIR chlorophyll fluorescence can be imaged in daylight without external lighting, thus, it is much easier to do than visible fluorescence imaging done at night. The distributions of chlorophyll and GFPs are unique in every species examined, and while there are some tissues where both fluorophores are co-resident, often tissues are selectively enriched in only one of these fluorescent pigments. Although laboratory studies have clearly shown that GFPs can be photo-protective, their inability to prevent large scale bleaching events in situ may be due to their limited tissue distribution.

scholarly journals A Novel Ratiometric Probe Based on Nitrogen-Doped Carbon Dots and Rhodamine B Isothiocyanate for Detection of Fe3+in Aqueous Solution

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Lin Liu ◽  
Lu Chen ◽  
Jiangong Liang ◽  
Lingzhi Liu ◽  
Heyou Han
Keyword(s):  
Rhodamine B ◽  
Carbon Dots ◽  
Dynamic Range ◽  
Tap Water ◽  
Buffer Solution ◽  
Nitrogen Doped ◽  
Rhodamine B Isothiocyanate ◽  
Doped Carbon Dots ◽  
Nitrogen Doped Carbon ◽  
Ratiometric Probe

A ratiometric probe for determining ferric ions (Fe3+) was developed based on nitrogen-doped carbon dots (CDs) and rhodamine B isothiocyanate (RhB), which was then applied to selective detection of Fe3+in PB buffer solution, lake water, and tap water. In the sensing system, FePO4particles deposit on the surface of CDs, resulting in larger particles and surface passivation. The fluorescence (FL) intensity and the light scattering (LS) intensity of CDs can be gradually enhanced with the addition of Fe3+, while the FL intensity of RhB remains constant. The ratiometric light intensity of CDs LS and RhB FL was quantitatively in response to Fe3+concentrations in a dynamic range of 0.01–1.2 μM, with a detection limit as low as 6 nM. Other metal ions, such as Fe2+, Al3+, K+, Ca2+, and Co2+, had no significant interference on the determination of Fe3+. Compared with traditional probes based on single-signal probe for Fe3+detection, this dual-signal-based ratiometric probe exhibits a more reliable and stable response on target concentration and is characterized by easy operation in a simple fluorescence spectrophotometer.

scholarly journals Development of an Aptamer Based Luminescent Optical Fiber Sensor for the Continuous Monitoring of Hg2+ in Aqueous Media

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2372 ◽  
Author(s):  
Nerea De Acha ◽  
César Elosúa ◽  
Francisco J. Arregui
Keyword(s):  
Optical Fiber ◽  
Aqueous Solutions ◽  
Limit Of Detection ◽  
Tap Water ◽  
Aqueous Media ◽  
Optical Fiber Sensor ◽  
Fluorescence Emission ◽  
Fiber Sensor ◽  
Buffer Solution ◽  
Fluorescence Quencher

A fluorescent optical fiber sensor for the detection of mercury (Hg2+) ions in aqueous solutions is presented in this work. The sensor was based on a fluorophore-labeled thymine (T)-rich oligodeoxyribonucleotide (ON) sequence that was directly immobilized onto the tip of a tapered optical fiber. In the presence of mercury ions, the formation of T–Hg2+-T mismatches quenches the fluorescence emission by the labeled fluorophore, which enables the measurement of Hg2+ ions in aqueous solutions. Thus, in contrast to commonly designed sensors, neither a fluorescence quencher nor a complementary ON sequence is required. The sensor presented a response time of 24.8 seconds toward 5 × 10−12 M Hg2+. It also showed both good reversibility (higher than the 95.8%) and selectivity: the I0/I variation was 10 times higher for Hg2+ ions than for Mn2+ ions. Other contaminants examined (Co2+, Ag+, Cd2+, Ni2+, Ca2+, Pb2+, Mn2+, Zn2+, Fe3+, and Cu2+) presented an even lower interference. The limit of detection of the sensor was 4.73 × 10−13 M Hg2+ in buffer solution and 9.03 × 10−13 M Hg2+ in ultrapure water, and was also able to detect 5 × 10−12 M Hg2+ in tap water.

SYNTHESIS OF ZnS:Mn/SILICA CORE/SHELL MICROSPHERES WITH A COMBINATION OF SOL–GEL AND SELF-TEMPLATING TECHNIQUES

NANO ◽  
2014 ◽  
Vol 09 (03) ◽  
pp. 1450028
Author(s):  
QING ZHANG
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Fluorescence Emission ◽  
Core Shell ◽  
Reaction Conditions ◽  
Whole Process ◽  
Transmission Electron ◽  
Novel Method ◽  
Nanosilica Particles

Core/shell microspheres with functional Mn -doped ZnS microspheres ( ZnS : Mn ) as core and with nanosilica particles as shell were prepared by a combination of sol–gel and self-templating techniques. The characteristic of this novel method was that the whole process required neither additional surfactant nor stabilizer, which exempted from removing the template and reduced reaction steps compared to the conventional process. The morphologies, structure and particle size distribution of the resulting ZnS : Mn / SiO 2 microspheres were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS), respectively. Surface chemical composition and optical properties were determined with X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectroscopy, respectively. In addition, the effects of reaction conditions on the structure and morphologies were investigated. Experimental results indicated that the resulting ZnS : Mn / SiO 2 microspheres were perfectly spherical with distinct core/shell structures, and exhibited stronger fluorescence emission.

scholarly journals A novel method for observing proteins in vivo using a small fluorescent label and multiphoton imaging

2005 ◽  
Vol 390 (3) ◽  
pp. 787-790 ◽  
Author(s):  
Stanley W. Botchway ◽  
Ignasi Barba ◽  
Randolf Jordan ◽  
Rebecca Harmston ◽  
Peter M. Haggie ◽  
...  
Keyword(s):  
Fluorescence Detection ◽  
Fluorescence Emission ◽  
Yeast Cells ◽  
Fluorescent Label ◽  
Multiphoton Imaging ◽  
Two Photon ◽  
Photon Excitation ◽  
Novel Method ◽  
Two Photon Excitation

A novel method for the fluorescence detection of proteins in cells is described in the present study. Proteins are labelled by the selective biosynthetic incorporation of 5-hydroxytryptophan and the label is detected via selective two-photon excitation of the hydroxyindole and detection of its fluorescence emission at 340 nm. The method is demonstrated in this paper with images of a labelled protein in yeast cells.

scholarly journals Validated Analytical Spectrofluorimetric Method for Quantitation of Diphenhydramine HCl in Commercial Dosage Forms

2018 ◽  
Vol 1 (4) ◽  
pp. 12-26
Author(s):  
Syed Najmul Hejaz Azmi ◽  
Aisha Al-Mahroqi ◽  
Khoula Al-Mamari ◽  
Shaima Al-Shukaili
Keyword(s):  
Dynamic Range ◽  
Fluorescence Emission ◽  
Reference Method ◽  
Pharmaceutical Formulations ◽  
Ion Pair ◽  
Ratio Method ◽  
Eosin Y ◽  
Stoichiometric Ratio ◽  
Buffer Solution

Diphenhydramine HClis a weakly fluorescent drug having tertiary amine group forming ion pair complex with eosin Y in dichloromethane at pH 5 in disodium hydrogen phosphate-citric acid buffer solution. The complex formation was the basis for the development of new analytical method for determination of active diphenhydramine in pharmaceutical formulations. The stoichiometric ratio between diphenhydramine and eosin Y was studied by mole ratio method and found to be 2:1. The ion-pair complex showed maximum fluorescence emission intensity at 554 nm with excitation at 259 nm. The linear dynamic range was obtained in the concentration range of 2-22 µg mL-1 with a linear equation of FI = 0.361 + 13.675 C. The apparent Gibb’s free energy (ΔGº) was calculated and found to be -80.783 KJ mol-1, confirmed the feasibility of the reaction. The proposed method was successfully applied to the determination of diphenhydramine HCl in pharmaceutical formulations and in good agreement with the reference method.

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