Fluorescent Dye Rhodamine Research Articles

Tunable multicolor afterglow including white light emission from poly(acrylic acid)-based room temperature phosphorescence materials via phosphorescence FRET

Room temperature phosphorescence (RTP) materials with multicolor afterglow emission have important application potential in multicolor display and anti-counterfeiting. However, the preparation of polymer-based multicolor RTP materials still faces challenges. In this work, we prepare a kind of ultralong RTP materials by facilely doping phthalimide (Pth) into poly (acrylic acid) (PAA) matrices based on the hydrogen-bonding interaction. Attributed to the wide phosphorescence emission band of PAA-Pth, the ternary doping systems are constructed by using PAA-Pth as donors and commercially available fluorescent dyes rhodamine B (RhB) or fluorescein (FL) as acceptors, which display multicolor afterglow from cyan to red and green through efficient phosphorescence Förster resonance energy transfer (FRET). More impressively, the quaternary doping systems PAA-Pth-RhB-FL with different molar ratios of FL exhibit tunable multicolor afterglow, including nearly white afterglow emission. Due to the different FRET efficiency of PAA-based multicolor RTP materials at different excitation wavelengths, they are successfully applied in color information encryption.

Fluorescent and Colorimetric Dual-Mode Strategy Based on Rhodamine 6G Hydrazide for Qualitative and Quantitative Detection of Hg2+ in Seafoods.

In this study, a rapid fluorescent and colorimetric dual-mode detection strategy for Hg2+ in seafoods was developed based on the cyclic binding of the organic fluorescent dye rhodamine 6G hydrazide (R6GH) to Hg2+. The luminescence properties of the fluorescent R6GH probe in different systems were investigated in detail. Based on the UV and fluorescence spectra, it was determined that the R6GH has good fluorescence intensity in acetonitrile and good selective recognition of Hg2+. Under optimal conditions, the R6GH fluorescent probe showed a good linear response to Hg2+ (R2 = 0.9888) in the range of 0-5 μM with a low detection limit of 2.5 × 10-2 μM (S/N = 3). A paper-based sensing strategy based on fluorescence and colorimetric analysis was developed for the visualization and semiquantitative analysis of Hg2+ in seafoods. The LAB values of the paper-based sensor impregnated with the R6GH probe solution showed good linearity (R2 = 0.9875) with Hg2+ concentration in the range of 0-50 μM, which means that the sensing paper can be combined with smart devices to provide reliable and efficient Hg2+ detection.

Ch][TAPSO] As an Efficient Ionic Liquid Catalyst for One‐Pot Synthesis ofTetrahydro‐4H‐chromenes and 3,4‐Dihydropyrano[c]chromenes

AbstractCholinium N‐Tris(hydroxymethyl)methyl‐3‐amino‐2‐hydroxypropanesulfonate [Ch][TAPSO] has been found as an efficient ionic liquid catalyst for the synthesis of tetrahydro‐4H‐chromenes and 3,4‐dihydropyrano[c]chromenes in water and EtOH : Water (3 : 2) respectively. [Ch][TAPSO] being a basic IL has also been observed to extract acidic compounds such as rhodamine B from IL‐ immiscible organic solvent such as acetone through acid‐base interaction. The extraction process of fluorescent dye rhodamine B was determined by ultraviolet‐visible (UV‐Vis) spectroscopy. The observed percentage extraction rate is 100 % upto 6 mM solution of rhodamine in acetone. This method results in faster reaction with operational simplicity and excellent yields of the products. Furthermore, the catalyst has a great capacity for reutilisation.

Enhanced Luminescence of Dye-Decorated ZIF-8 Composite Films via Controllable D-A Interactions for White Light Emission.

Metal-organic frameworks (MOFs) constructed by metal ions/clusters and organic linkers are used to encapsulate fluorescent guest species with aggregation-caused quenching (ACQ) effects to enhance fluorescence properties due to their porous structures and high specific surface areas. However, there would be a problem of matching between MOF pores and guest molecules' sizes. In this paper, amorphous ZIF-8 was modified by carboxyl functional groups (H3BTC-ZIF-8) via introducing the 1,2,4-benzenetricarbonic acid (H3BTC) ligand into the ZIF-8 sol system. Moreover, H3BTC-ZIF-8 was used for the loading of organic fluorescent dyes rhodamine 6G (R6G) and coumarin 151 (C151) to prepare R6G/C151/H3BTC-ZIF-8 composite films. A white-light-emitting composite film (R6G/C151/H3BTC-ZIF-8) with CIE coordinates of (0.323, 0.347) was successfully prepared by compounding fluorescent dyes (R6G and C151) with H3BTC-modified ZIF-8, whose photoluminescence quantum yield (PLQY) can reach 64.0%. It was higher than the PLQY of the composite films prepared by crystalline ZIF-8 (40.2%) or amorphous ZIF-8 without H3BTC (48.0%) compounded with the same concentrations of dyes. The fluorescence enhancement was probably attributed to an increased amount of active sites of H3BTC-modified ZIF-8 interacting with dyes C151 and R6G. This can form hydrogen bonds between H3BTC-ZIF-8 and C151, and weak electron donor-acceptor (D-A) interactions between H3BTC-ZIF-8 and R6G molecules, respectively, thus enhancing the interactions between dyes and ZIF-8 and reducing the ACQ effect existing between dye molecules. Therefore, this strategy could provide an important guidance to develop white-light-emissive materials.

The Formation of Morphologically Stable Lipid Nanocarriers for Glioma Therapy

Cerasomes are a promising modification of liposomes with covalent siloxane networks on the surface that provide outstanding morphological stability while maintaining all the useful traits of liposomes. Herein, thin film hydration and ethanol sol injection methods were utilized to produce cerasomes of various composition, which were then evaluated for the purpose of drug delivery. The most promising nanoparticles obtained by the thin film method were studied closely using MTT assay, flow cytometry and fluorescence microscopy on T98G glioblastoma cell line and modified with surfactants to achieve stability and the ability to bypass the blood-brain barrier. An antitumor agent, paclitaxel, was loaded into cerasomes, which increased its potency and demonstrated increased ability to induce apoptosis in T98G glioblastoma cell culture. Cerasomes loaded with fluorescent dye rhodamine B demonstrated significantly increased fluorescence in brain slices of Wistar rats compared to free rhodamine B. Thin film hydration with Tween 80 addition was established as a more reliable and versatile method for cerasome preparation. Cerasomes increased the antitumor action of paclitaxel toward T98G cancer cells by a factor of 36 and were able to deliver rhodamine B over the blood-brain barrier in rats.

Sol-gel coatings with the fluorescence dye Rhodamine B for optical modification of cotton

The sol-gel method is a versatile tool for the modification and functionalization of textiles. This method can be also used to support the application of dyes on textile materials. This paper is related to the application of the fluorescence dye Rhodamine B together with an industrial sol-gel component. Beside fluorescence spectroscopy, also scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) are used for the investigation of the produced textile samples. The realized fluorescence effects are strongly related to the applied dye concentration and can be drastically enhanced by presence of the applied sol-gel system. By use of sol-gel method also the dry and the wet rubbing fastness can be improved. These results could be the starting point for future development of new fluorescent textile materials.

Effect of different sealer activation techniques on dentinal tubule penetration.

The aim of this study was to evaluate the influence of different activation techniques on dentin tubule penetration of root canal sealer. Seventy-five teeth with single canals were chemomechanically prepared. A calcium silicate-based sealer was stained with a fluorescent dye (rhodamine B), placed into the canals and activated according to the following groups: control (no activation), EDDY, EndoActivator, ultrasonic and XP-Endo Finisher. Then, the samples were obturated. The percentages of sealer penetration at various depth levels of root sections were measured with confocal laser scanning microscopy. XP-Endo Finisher presented the highest penetration at 50 μm (p < 0.05). XP-Endo Finisher showed similar penetration with EDDY at 100 and 200 μm (p > 0.05) while presented higher penetration than the other groups (p < 0.05). At 500 μm, XP-Endo Finisher presented higher penetration than EndoActivator (p < 0.05) while similar penetration with the other groups (p > 0.05). XP-Endo Finisher can be recommended for activation during sealer placement for better penetration into dentin tubules.

Impact of solvent ratio on diphenyl oxalate chemiluminescence

This research studied the effect of solvent ratio on chemiluminescence widely applied in glow sticks using dichloromethane and ethyl acetate as solvents. The fluorescent solution, as a mixture of diphenyl oxalate solvent and fluorescent dye rhodamine B, was stimulated by a 405 nanometre laser for fluorescent spectrum measurement before the chemiluminescence experiment. The fluorescent solution concentration and solvent ratio were varied. For the chemiluminescence experiment, diphenyl oxalate was dissolved in the solvents and combined with rhodamine B that interacted with a mixture of hydrogen peroxide and acetonitrile, resulting in chemiluminescence. The duration and intensity of light were measured by a photodiode detector. Results revealed that the concentration and solvent ratio of the fluorescent solution impacted the fluorescent spectrum due to opacity and solubility. Increasing ethyl acetate and decreasing dichloromethane gave a longer duration of light. The intensity of light in some ratios alternated high and low. Light emitted for a long time at high intensity is suitable for applications. Solvent ratios at 3:7 and 5:5 (1:1) gave better results than the other samples.

Lock-In Amplified Fluorescence Spectroscopy in a Digital Microfluidic Configuration for Antibiotic Detection of Ciprofloxacin in Milk

Antibiotic detection in dairy is crucial, as introduction of antibiotics in food can lead to antibiotic resistance and cause allergic reactions in consumers. Dairy farmers risk monetary fines for shipping contaminated milk. Microfluidics is an appealing technology, as it is portable, can be implemented on-site, and is highly automated. This work presents a digital microfluidic dairy device for antibiotic detection. The digital microfluidic dairy device explores integration of a lock-in amplifier with droplet-based microfluidic techniques, being electrowetting actuation and droplet control. The lock-in amplifier setup is initially demonstrated for the fluorescent dye rhodamine B, to establish baseline operation. Ultimately, the lock-in amplifier setup is demonstrated for detection of ciprofloxacin in milk. The limit of detection is significantly lowered through the integration of the lock-in amplifier technology. Actuation of milk and water samples is shown, demonstrating full two dimensional control over the position of water and milk droplets, to enable a complete lab-on-a-chip system. The results show promise for modern dairy testing of antibiotic signatures. [2022-0120]

Live-cell imaging of the chloroplast outer envelope membrane using fluorescent dyes.

We established a live-cell imaging method to visualize the chloroplast outer envelope membrane by staining living cells with fluorescent dyes. This method does not require genetic transformation and allows the observation of the chloroplast outer envelope membrane in various plant species.

Portuino-A Novel Portable Low-Cost Arduino-Based Photo- and Fluorimeter.

A novel portable low-cost Arduino-controlled photo- and fluorimeter for on-site measurements has been developed. The device uses LEDs as a light source and a phototransistor as a light sensor. The circuit is based on the discharge of a capacitor with the photocurrent from the phototransistor. Validation experiments for absorbance measurements were performed by measuring protein concentration using the Bradford method and measuring phosphate ions in water using a commercial test kit. The emission light of the excited fluorescent dyes rhodamine 6G and calcofluor white was measured to validate the usability of the device as a fluorescence photometer. In all validation experiments, similar correlation coefficients and limit of detection could be achieved with the portable photo- and fluorimeter and a laboratory spectrometer and fluorimeter. Real sample analysis was performed, measuring phosphate concentration in freshwater and concentration of green fluorescent protein, extracted from Escherichia coli.

Effect of fluorescence dyes on wet gluten structure studied with fluorescence and FT-Raman spectroscopies

Fluorescence spectroscopy coupled with FT-Raman spectroscopy were used to determine effect of two fluorescent dyes (fluorescein and rhodamine B) on the structure of wet gluten (hydrated gluten). Additionally, PCA analysis was applied to find correlations between fluorescence and Raman parameters. The fluorescent dyes, regarded as model representatives of phenolic compounds, were added to model dough in six concentrations (0.05%–0.5%). Wet gluten samples and starch slurries (as a residue after washing out gluten) were excited by two wavelengths – one assigned to tryptophan, and the second to the particular dye. Fluorescence and UV-VIS analysis of starch slurries show that the dyes can be completely bound to gluten proteins because of their absence in the slurries. Analysis of the spectroscopic results indicate that fluorescein and rhodamine B interact with gluten proteins in different ways depending on the type of functional groups present in the dye structure. The fluorescein molecules, due to the presence of hydroxyl and carboxyl groups may incorporate into gluten network by forming hydrogen and/or covalent bonds, whereas rhodamine B with four methyl groups may be enclosed in hydrophobic pockets formed by gluten polypeptide chains. These differences can be related to the type of functional groups present in the dye structure (fluorescein has one hydroxyl group, rhodamine B has four methyl groups). PCA analysis showed correlations between dye fluorescent parameters (maximum wavelength and band intensity) and some structural parameters (presence or absence of bands assigned to α-helices, β-turns and S S bonds conformations). The PCA results also suggest that mechanism of interactions gluten – dye depends on type of functional groups present in the dye molecule. • Interactions between gluten and dyes depend on functional groups present in dye. • Fluorescein with hydroxyl and carboxyl groups can incorporate into gluten network. • Rhodamine B with four methyl groups may be enclosed in hydrophobic pockets. • Structural changes observed in gluten network depend on the dye concentration. • Fluorescence spectra of TRP may indicate type of gluten-polyphenols interactions.

Red-emitting rhodamine-based probe with large Stokes shift for ClO− detection

A fluorescent rhodamine dye, HN, was prepared by introducing tetrahydroquinoxalinyl donor, which displayed far-red emission (687 nm), large Stokes shift (84 nm), and relatively high fluorescent quantum yield (0.33). Based on HN dye, a fluorescent probe, HN-HClO, was developed for hypochlorite (ClO−) detection. The probe HN-HClO exhibited fast response time (within 100 s), excellent sensitivity (LOD = 74 nM), and good selectivity toward ClO−. The probe HN-HClO was capable of imaging ClO− in both living cells and zebrafish. It could also monitor the endogenously generated ClO− in the MPO-catalyzed system.

Method of manufacturing and staining microplastics for using in the biological experiments.

Nowadays, plastic pollution attracts much attention both from society and scientists. The plastic pollution impact on the environment and human health requires assessment urgently, especially through experimental studies. However, such studies are still scarce because of the lack of standard methods for assessing their effects on living organisms. We have developed a process for manufacturing and staining PVC microparticles for using them in biological and ecological experiments. The electrospinning method has been used to manufacture PVC particles; their morphology and size have been analyzed. The obtained PVC particles are of narrow size range averaging 2-4µm in diameter. They are successfully stained with the fluorescent dye Rhodamine B, which stands for the experiments performed in the seawater.

Detection of ochratoxin A by fluorescence sensing based on mesoporous materials.

We developed a new ochratoxin A (OTA) aptamer biosensor to promptly detect OTA in food. Mesoporous silica nanoparticles were used as carriers, and aptamers were used as recognition probes and gating molecules. The fluorescent dye rhodamine 6G was loaded into mesoporous silica, and through electrostatic contact, the OTA aptamer was adsorbed on amino-modified mesoporous silica. The fluorescent dye released from the mesopore in the presence of OTA because of the conformational change induced in the aptamer by the target. The amount of ochratoxin was determined by measuring the fluorescence intensity. Our findings revealed a positive relationship between the fluorescence intensity and OTA concentration, with a limit of detection of 0.28 ng mL-1, and the detection range was 0.05-200 ng mL-1. The recovery rate was 80.7%-110.8% in real samples. The proposed approach is suitable for the quantification of other toxins.

Depolarized Mitochondrial Membrane Potential and Protection with Duroquinone in Isolated Perfused Lungs from Rats Exposed to Hyperoxia

ObjectiveDissipation of mitochondrial membrane potential (Δψm) is a hallmark of mitochondrial dysfunction, which plays a key in the pathogenesis of Acute Respiratory Distress Syndrome (ARDS). Our objective was to use a previously developed experimental‐computational approach to estimate tissue Δψm in isolated perfused lungs of rats exposed to hyperoxia as a rat model of human ARDS, and to evaluate the ability of the ubiquinone analog duroquinone (DQ) to reverse any hyperoxia‐induced depolarization of lung Δψm.MethodsRats were exposed to hyperoxia (&gt;95% O2) or normoxia (room air) for 48 hrs, after which lungs were excised and connected to a ventilation‐perfusion system. The experimental protocol consisted of measuring the concentration of the fluorescent dye rhodamine 6G (R6G) during three single‐pass phases: loading, washing, and uncoupling, in which the lungs were perfused with and without R6G, and with the mitochondrial uncoupler FCCP, respectively. For normoxic lungs, the protocol was repeated with 1) rotenone (mitochondrial complex I inhibitor), 2) rotenone and either DQ or its vehicle (DMSO), and 3) rotenone, glutathione (GSH), and either DQ or DMSO added to the perfusate. Hyperoxic lungs were studied with and without DQ and GSH added to the perfusate. A physiologically‐based pharmacokinetic (PBPK) computational model was used to estimate lung Δψm from R6G data.ResultsFigure 1 shows that for hyperoxic lungs, R6G venous effluent concentrations tended to be higher during the loading phase, but significantly lower during the uncoupling phase compared to normoxic lungs, consistent with less uptake of R6G by hyperoxic lungs due to partial depolarization of Δψm. Figure 1 also shows that adding DQ to perfusate during the three phases almost completely reversed differences in R6G concentrations between normoxic and hyperoxic lungs. The PBPK computational model analysis of the R6G data show that exposure to hyperoxia depolarized lung tissue Δψm from ‐140 ± 9 (SE, n = 5) mV to ‐107 ± 9 (n = 5) mV, and complex I inhibition depolarized lung Δψm from ‐140 ± 9 (n = 5) to ‐57 ± 2 (n = 4) mV. Computational model analysis results also demonstrate the efficacy of DQ to fully reverse both rotenone‐induced and hyperoxia‐induced lung Δψm depolarization, consistent with the ability of the lungs to reduce DQ to its hydroquinone form (DQH2), which in turn bypasses mitochondrial complexes I and II to reduce mitochondrial complex III and restores Δψm.ConclusionsThis study demonstrates hyperoxia‐induced Δψm depolarization in isolated perfused lungs, and the utility of this approach for assessing the impact of potential therapies such as exogenous quinones that target mitochondria in isolated perfused lungs.

Design of a thermosensitive ibuprofen-loaded nanogel as smart material applied as anti-inflammatory in tooth bleaching: An in vivo study

The in vivo ability of thermosensitive nanogel containing ibuprofen for bioadhesion on the surface of teeth submitted to bleaching and drug delivery through dentinal tubules to the dental pulp are evaluated in Wistar rats. Drug-loaded self-assembled oil in water nanoemulsions present droplet size <150 nm and negative zeta potential. Nanoemulsions containing poloxamer 407 in the aqueous phase exhibit reduced droplet size, improved physical stability, controlled the thermosensitive viscosity, and slow drug release. Different treated animals' groups included a control group (CTRL); bleached animals (BLE) (37.5% H2O2, Pola Office Plus®, SDI); bleached animals treated with a conventional ibuprofen-loaded hydrogel (BLE + IBF-GEL), and bleached animals treated with thermosensitive ibuprofen-loaded nanogel (BLE + IBF-NEG). Compared to the BLE + IBF-GEL group, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) images show the superior ability of BLE + IBF-NEG group to offer a physical barrier on the tooth surface, pores occlusion, and transport the fluorescent dye rhodamine B to dental pulp. Morphological analysis revealed the lowest inflammatory infiltrate scores and absence of necrosis for BLE + IBF-NEG group after 24 h and 14 days. Immunohistochemical studies reinforced this hypothesis. The experimental data presented in this study confirm the incredible potential for topical and easy application of a novel and smart nanogel, as analgesic and anti-inflammatory treatment for bleaching procedure.

Simultaneous velocity profile and temperature profile measurements in microfluidics

Simultaneous non-intrusive temperature and velocity measurements in flows are of high technological interest, e.g. to study the heat transfer in microfluidic environments. However, a measurement system that offers a low velocity uncertainty and micrometre spatial resolution as well as highly accurate temperature measurements in a single device has not been demonstrated so far. In this work, this problem is solved by combining a Laser Doppler Velocity Profile Sensor (LDV-PS) with Laser-Induced Fluorescence (LIF). Seeding particles are employed, that contain the fluorescent dyes uranine and rhodamine B. The multiple dye approach eliminates the influence of the droplet size. Relative velocity uncertainties of down to 0.4% and a temperature uncertainty of down to 0.24∘C with a spatial resolution of 10μm are achieved in a demonstration air flow experiment. The method has the potential to be optimised for different temperature ranges and uncertainty requirements, making it applicable on a wide range of thermal flows like fuel cells or microbioreactors. A better understanding of heat exchange processes can improve the energy efficiency of microfluidic devices.

N-Methyl deuterated rhodamines for protein labelling in sensitive fluorescence microscopy.

Rhodamine fluorophores are setting benchmarks in fluorescence microscopy. Herein, we report the deuterium (d12) congeners of tetramethyl(silicon)rhodamine, obtained by isotopic labelling of the four methyl groups, show improved photophysical parameters (i.e. brightness, lifetimes) and reduced chemical bleaching. We explore this finding for SNAP- and Halo-tag labelling in live cells, and highlight enhanced properties in several applications, such as fluorescence activated cell sorting, fluorescence lifetime microscopy, stimulated emission depletion nanoscopy and single-molecule Förster-resonance energy transfer. We finally extend this idea to other dye families and envision deuteration as a generalizable concept to improve existing and to develop new chemical biology probes.

Depolarized mitochondrial membrane potential and protection with duroquinone in isolated perfused lungs from rats exposed to hyperoxia.

Dissipation of mitochondrial membrane potential (Δψm) is a hallmark of mitochondrial dysfunction. Our objective was to use a previously developed experimental-computational approach to estimate tissue Δψm in intact lungs of rats exposed to hyperoxia and to evaluate the ability of duroquinone (DQ) to reverse any hyperoxia-induced depolarization of lung Δψm. Rats were exposed to hyperoxia (>95% O2) or normoxia (room air) for 48 h, after which lungs were excised and connected to a ventilation-perfusion system. The experimental protocol consisted of measuring the concentration of the fluorescent dye rhodamine 6 G (R6G) during three single-pass phases: loading, washing, and uncoupling, in which the lungs were perfused with and without R6G and with the mitochondrial uncoupler FCCP, respectively. For normoxic lungs, the protocol was repeated with 1) rotenone (complex I inhibitor), 2) rotenone and either DQ or its vehicle (DMSO), and 3) rotenone, glutathione (GSH), and either DQ or DMSO added to the perfusate. Hyperoxic lungs were studied with and without DQ and GSH added to the perfusate. Computational modeling was used to estimate lung Δψm from R6G data. Rat exposure to hyperoxia resulted in partial depolarization (-33 mV) of lung Δψm and complex I inhibition depolarized lung Δψm by -83 mV. Results also demonstrate the efficacy of DQ to fully reverse both rotenone- and hyperoxia-induced lung Δψm depolarization. This study demonstrates hyperoxia-induced Δψm depolarization in intact lungs and the utility of this approach for assessing the impact of potential therapies such as exogenous quinones that target mitochondria in intact lungs.NEW & NOTEWORTHY This study is the first to measure hyperoxia-induced Δψm depolarization in isolated perfused lungs. Hyperoxia resulted in a partial depolarization of Δψm, which was fully reversed with duroquinone, demonstrating the utility of this approach for assessing the impact of potential therapies that target mitochondria such as exogenous quinones.