The ORAC assay was carried out as described by Dávalos et al. [24 (link)]. The reaction was carried out in phosphate buffer (75 mM, pH 7.4), and the final reaction volume was 200 µL. In a 96-well microplate, 20 µL of each sample and 120 µL of fluorescein (Sigma-Aldrich, Steinheim, Germany) (70 mM) were added. The mixture was pre-incubated at 37 °C for 15 min. After this period, 60 µL of the 2,2′-Azobis(2-methylpropionamidine) dihydrochloride (AAPH) solution (Sigma-Aldrich, Steinheim, Germany) were added. The plate was placed in the microplate reader (Multimodal Synergy H1, BioTek® Instruments, Winooski, VT, USA), and fluorescence (excitation: 458 nm; emission: 520 nm) was recorded every minute for 180 min and automatically shaken before each reading. Eight calibration solutions were prepared using Trolox (Merck, Darmstadt, Germany) (0–80 μM) as an antioxidant standard; a blank was also conducted using phosphate buffer instead of fluorescein. ORAC values were expressed in μmol of Trolox equivalents/g extract (μmol TE/g extract).
Fluorescein
Manufactured by Merck Group
Sourced in United States, Germany, United Kingdom, Italy, France, Sao Tome and Principe, Canada, China, Spain, Brazil, Japan, Switzerland, Mexico, Belgium
Fluorescein is a fluorescent dye used in various laboratory applications. It absorbs light in the blue-green region of the visible spectrum and emits light in the yellow-green region, making it a useful tool for fluorescence-based techniques. Fluorescein can be used to label and track biological molecules, cells, or other samples in a wide range of scientific investigations.
Automatically generated - may contain errors
Lab products found in correlation
Trolox, by Merck Group (67 mentions)
Gallic acid, by Merck Group (48 mentions)
2 2 diphenyl 1 picrylhydrazyl (dpph), by Merck Group (36 mentions)
2 2 azobis 2 methylpropionamidine dihydrochloride, by Merck Group (22 mentions)
Methanol, by Merck Group (19 mentions)
Dimethyl sulfoxide (dmso), by Merck Group (19 mentions)
Acetonitrile, by Merck Group (19 mentions)
Potassium persulfate, by Merck Group (18 mentions)
Formic acid, by Merck Group (18 mentions)
Folin ciocalteu reagent, by Merck Group (18 mentions)
Hydrochloric acid (hcl), by Merck Group (17 mentions)
Ethanol, by Merck Group (17 mentions)
Sodium carbonate, by Merck Group (15 mentions)
2 2 azobis 2 amidinopropane dihydrochloride, by Merck Group (14 mentions)
Bovine serum albumin (bsa), by Merck Group (13 mentions)
Sodium chloride (nacl), by Merck Group (12 mentions)
Sodium hydroxide (naoh), by Merck Group (12 mentions)
Acetic acid, by Merck Group (11 mentions)
Quercetin, by Merck Group (11 mentions)
2 2 azobis 2 methylpropionamidine dihydrochloride aaph, by Merck Group (11 mentions)
364 protocols using fluorescein
1
Antioxidant Capacity Evaluation using ORAC
2
Evaluating Colon Barrier Function
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Six tissue samples from the sigmoid colon were used for ex vivo Ussing chamber experiments as previously described by our group [27 (link)]. Three tissue samples were mildly stressed by adding 1 µg/mL of the mast cell degranulator Compound 48/80 (Sigma-Aldrich, St. Louis, MO, USA) to the serosaL compartment. Three non-exposed tissue samples served as unstressed controls. At t = 0, 1 mg/mL fluorescein (376 g/mol, Sigma-Aldrich, St. Louis, MO, USA) was added to the serosal compartment for determination of fluorescein flux to the luminal compartment. From all tissue samples, potential difference (PD), transepithelial electrical resistance (TEER), and fluorescein concentrations were determined at time point t = 0, 30, 60, 80, and 120 min. TEER and PD were used as quality criteria for viability. Only samples with a baseline TEER above 20 Ω/cm2, or those with baseline TEER between 15–20 Ω/cm2 and PD below 0.5 mV, were included for analyses. TEER and fluorescein concentrations are indicators of intestinal permeability.
3
Inducing Acute Dry Eye Disease in Mice
4
Diffusion Rates of Bioactive Molecules in Printed Hydrogels
5
Wheat Flour Dough Microstructure Analysis
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Epifluorescence light microscopy (EFLM) was used to characterize the microstructure of wheat flour dough with different levels of tomato seed flour addition. Dough microstructure was analyzed using a Motic AE 31 inverted microscope (Motic, Optic Industrial Group, Xiamen, China) operated by catadioptric objectives LWD PH 203 (N.A. 0.4). A thin portion was cut from the dough sample and dipped in a fixing solution composed of 1% rhodamine B and 0.5% fluorescein (FITC) in 2-methoxyethanol obtained from Sigma-Aldrich, Germany for at least 1 h. fluorescein and rhodamine B was used as two fluorescent dyes specific for detecting starch and proteins in the dough samples. fluorescein detects starch and rhodamine B proteins from the dough system. The EFLM images were analyzed using ImageJ (v. 1.45, National Institutes of Health, Bethesda, MD, USA) software according to Peighambardoust et al. [44 (link)] and Codină and Mironeasa [45 ,46 (link)].
6
Measuring Enteroid Luminal Volume
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Enteroids at day 3 of culture were treated with 1 μM Rh123 (Sigma-Aldrich) for 180 min at 37 °C and 1 μm Z-stack images were acquired. The luminal volume of enteroid was measured as accumulated Rh123 in enteroid lumen using by 3D measurement tool in NIS-elements AR. For measurement of injection volume, fluorescein and mineral oil (Sigma-Aldrich) were loaded into the needle in the order and the diameters of the interface between fluorescein and mineral oil before and after microinjection and moving distance by microinjection were measured.
7
Multicolor Film Fabrication via Coloring
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The film samples were cured by shining grayscale pattern light on the hybrid resin sandwiched between glass slides for 20 s and then using the same thermal curing conditions. The thickness of the films was defined by plastic spacers (with thickness of 0.1 to 0.3 mm). The coloring process was conducted by immersing the film sample in dye or fluorescein solution for different times. The fluorescein solution contained 0.15 wt % of fluorescein (Sigma-Aldrich, St. Louis, MO) in acetone. The dye solution contained 10 to 15 wt % of cyan or black color ink [Hewlett-Packard (HP), Palo Alto, CA] in acetone/isopropyl alcohol (1/5, w/w). The coloring process using the dye took about 2 to 3 hours for film, and the encryption in fluorescein solution took only 10 to 20 s. Afterward, the samples were washed with isopropyl alcohol several times followed by drying. The fluorescein-treated samples were observed under a UV lamp (OmniCure S2000, Excelitas Technologies Corp., Waltham, MA) with a 320- to 390-nm filter. All the colored samples were recorded by a digital camera, and the color was analyzed by ImageJ using the Color Profiler tool.
8
Synthesizing Multimodal Nanoparticles
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Dextran-coated iron oxide nanoparticles of diameter 5-10 nm with 10 mg/ml concentration were bought from Ocean Nanotech, USA. 0.5 ml of iron oxide solution was added to 1.5 ml of phosphate buffer saline (PBS, 100 mM) (Sigma Aldrich) containing Gd (III)-DTPA (Sigma Aldrich) and fluorescein (Sigma Aldrich) to obtain a 2 ml hydrating solution with a final concentration of 200 mM Gd (III)-DTPA and 100 mM fluorescein at pH 7.4.
9
Quantifying Cellular Uptake of Fluorescent Polymeric Micelles
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L929 cells were seeded in a 6 well plate at a density of 100,000 cells/well and incubated for 24 hours with increasing concentrations of fluorescein-loaded PMs (from 5 × 1010 to 2 × 1012 PMs ml−1). Then, cells were washed with PBS twice to remove the excess of PMs that were not internalised and lysed using a solution of HEPES (20 mM), NaCl (125 mM) and sodium dodecyl sulphate (SDS) (2%). The relative optical density (O.D.) was measured at 521 nm using a Varioscan Flash microplate reader (Thermo Fisher Scientific, Basingstoke, UK). A fluorescein calibration curve was produced by dilution of a stock solution of fluorescein (100 mM) (Sigma-Aldrich, Poole, UK) in PBS supplemented with cell lysate. Mass of fluorescein PM−1 was calculated as the ratio between the mass of fluorescein present in PMs solution by the concentration of PMs ml−1. For quantification at the single cell level, raw data was extracted from FCS files using Matlab (Mathworks, Cambridge, UK) and analysed using Microsoft Excel.
10
Synthesis of Multifunctional Nanoparticles
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Ammonium hydroxide solution (25% NH3 in H2O), paraffin wax, 3-aminopropyl triethoxysilane (APTES), ε-caprolactone, triethylamine (TEA), Tin(II) 2-ethylhexanoate Sn(Oct)2, acryloyl chloride(AC), DL-malic acid, cisplatin, Candida Antarctica Lipase B (CALB, with 3.14 U/L lipase activity, (Supplementary Section S1.1 )), sodium bis(2-ethylhexyl) sulfosuccinate (AOT), fluorescein, acridine orange, and dimethylformamide (DMF) were purchased from Merck Chemical Company. 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC), N-Hydroxysuccinimide (NHS) 98%, iron (II) chloride tetrahydrate (FeCl2(4H2O)) and iron (III) chloride hexahydrate(FeCl3(6H2O)) were obtained from Sigma-Aldrich. Chitosan oligosaccharide ( = 3000 g/mol) was purchased from Golden-Shell Pharmaceutical Company (Ltd.), China. Ethanol, chloroform, and phosphate-buffered saline (PBS, pH 7.4) were supplied from Kian Kaveh, Iran.
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