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Abstract Background Obstructive jaundice induces oxidative changes in the brain parenchyma and plays significant role in clinical manifestations of hepatic encephalopathy. We aim to study the progression of the brain oxidative status over time and the differences of its pattern over the hemispheres, the brainstem and the cerebellum. We use an experimental model in rats and measuring the oxidative stress (OS) specific biomarkers protein malondialdehyde (PrMDA) and protein carbonyls (PrC = O). Results Hyperbilirubinemia has been confirmed in all study groups as the result of common bile duct obstruction. We confirmed increase in both PrMDA and PrC = O biomarkers levels with different type of changes over time. We also confirmed that the oxidative process develops differently in each of the brain areas in study. Conclusions The present study confirms the progressive increase in OS in all brain areas studied using markers indicative of cumulative protein modification.

A kind of functional luminescent small molecule probe (RCAIM) was designed and synthesized by using rhodamine B hydrazide as the fluorophore and cyanuric chloride and isophorone as raw materials to modify the main fluorophore. The probe could specifically recognize Cu2+ in ethanol and aqueous solution (v/v=95∶5). When the probe was binded with Cu2+ to form a complex, the color of the solution changed from yellow to red. The results showed that the probe formed a complex with Cu2+ in the form of 1:2 when Cu2+ is added to the probe solution, and the complex showed strong specific absorption at the wavelength of 555 nm. Meanwhile, the study showed that the probe had good specificity, selectivity and anti-interference ability for Cu2+ detection. At the same time, the detection limit of Cu2+ by the probe was 0.9×10-6 mol/L, indicating it had high sensitivity. And the probe could also be used to detect Cu2+ in lake water and tap water samples with high accuracy and reliability. The probe was also prepared into a portable test strip to detect Cu2+ conveniently and quickly. [ABSTRACT FROM AUTHOR]

Background: Obstructive jaundice induces oxidative changes in the brain parenchyma and plays significant role in clinical manifestations of hepatic encephalopathy. We aim to study the progression of the brain oxidative status over time and the differences of its pattern over the hemispheres, the brainstem and the cerebellum. We use an experimental model in rats and measuring the oxidative stress (OS) specific biomarkers protein malondialdehyde (PrMDA) and protein carbonyls (PrC = O). Results: Hyperbilirubinemia has been confirmed in all study groups as the result of common bile duct obstruction. We confirmed increase in both PrMDA and PrC = O biomarkers levels with different type of changes over time. We also confirmed that the oxidative process develops differently in each of the brain areas in study. Conclusions: The present study confirms the progressive increase in OS in all brain areas studied using markers indicative of cumulative protein modification. [ABSTRACT FROM AUTHOR]

[Display omitted] • BPL is a common chemical inactivating reagent used in vaccines. • Via BPL carcinogenicity, its residual should be hydrolyzed completely in vaccines to avoid cytotoxicity. • BPL residual determination in vaccines is challenging due to its low concentration, presence in a complex mixture of vaccine and lack of suitable chromophore. • BPL derivatization with RBH was used to enhance analytical sensitivity and stabilize the BPL molecule for measurement with HPLC-UV. β-propiolactone (BPL) is an alkylating agent used for inactivation of biological samples such as vaccines. Due to its known carcinogenic properties, complete hydrolysis of BPL is essential, and the detection of trace amounts is crucial. In this study a novel High-Performance Liquid Chromatography-Ultraviolet (HPLC-UV) method was developed. Rhodamine B hydrazide (RBH) was synthesized and utilized as a derivatizing reagent to react with BPL. The reaction was optimized in a weak acidic solution, resulting in a high yield. The separation of the RBH-derivatized BPL was achieved on a C8 column and detected by a UV detector at a wavelength of 560 nm. The method's validation demonstrated a high linearity (r2 > 0.99) over a concentration range of 0.5–50 µg/mL, with detection and quantification limits of 0.17 µg/mL and 0.5 µg/mL, respectively. The average recovery of samples was 85.20 % with a relative standard deviation (RSD) of 1.75 %. This method was successfully applied for BPL residue analysis in inactivated COVID-19 vaccines. This novel derivatization method offers a promising solution for monitoring BPL residues in the vaccine production process for quality control purposes and compliance with regulatory standards. [ABSTRACT FROM AUTHOR]

Using Rhodamine B hydrazide as the fluoroph ore, a fluorescent probe with disulfide bond, RNSS, is designed and synthesized, which can specifically recognize in acetonitrile and aqueous solution (v/v = 1 :1) glutathione (GSH). The structure characterization and performance of the probe are analyzed by infrared spectroscopy, nuclear magnetic resonance spectroscopy, and fluorescence spectroscopy. The experimental results show that when GSH is added to the probe solution, under the excitation of 561 nm light, it has obvious pink fluorescence at 585 nm, and other amino acids have no fluorescence response, indicating that it has good specific selectivity and anti--interference ability. At the same time, the detection limit of the probe for GSH is 6.063 X 1 ()_b mol/L, which indicates that it has high sensitivity. The fluorescence spectrum titration curve and Job-plot analysis show that the two are replaced by disulfide bond reaction 1 :1 method to form complexes. [ABSTRACT FROM AUTHOR]

In this work, different materials were fabricated from cellulose acetate, loaded with rhodamine B hydrazide and tested as Cu(II) optical sensor. We prepared membranes displaying a sub-micron porous structure using the phase inversion technique, clusters of fibers with varying diameter depending on the preparation procedure using electrospinning, and casted films presenting a smooth non porous structure. Loading of rhodamine B hydrazide on the fabrics after their production was found to be the best procedure to ensure the stability of the dye in the polymeric materials. Absorption and emission analysis of the solid substrates revealed the presence of the dye on the porous fabrics and allowed to choose the most suited materials and loading conditions to test their response towards Cu(II) ions. Reaction of the loaded rhodamine B hydrazide with Cu(II) was confirmed by absorption and emission spectroscopies and by confocal fluorescence imaging, through detection of the product rhodamine B. The results point to promising sensing applications of the prepared composite materials.

The rational surface functionalization of semiconducting polymer dots (Pdots) has attracted much attention to extend their applications in fabricating chemo/biosensing platform. In this study, a novel ratiometric fluorescent sensing platform using functionalized Pdots as probes for fluorescence signal transmission has been designed for sensing Cu(Ⅱ) and activity of alkaline phosphatase (ALP) with high selectivity and enhanced sensitivity. The highly fluorescent Pdots were firstly prepared with Poly[(9,9-dioctylfluorenyl-2,7-diyl)- co -(1,4-benzo-{2,1′,3}-thiadiazole)] (PFBT) via nanoprecipitation method, and then assembled with non-fluorescent rhodamine B hydrazide (RB-hy), which shows special binding activity to Cu(Ⅱ), through adsorption process to obtain functionalized nanohybrids, Pdots@RB-hy. As thus, a FRET donors/acceptors pair, in which PFBT Pdots act as energy donors while RB-hy-Cu(II) complexes act as energy acceptors were constructed. On the basis of the varies in fluorescence intensities of donors/acceptors in the presence of different amounts of Cu(II), a ratiometric method for sensing Cu(II) has been proposed. The proposed ratiometric Cu(II) sensor shows a good linear detection range from 0.05 to 5 μM with a detection limit of 15 nM. Furthermore, using the Pdots@RB-hy-Cu(II) system as signal transducer, a ratiometric sensing for alkaline phosphatase (ALP) activity has also been established with pyrophosphate (PPi) as substrates. The constructed ratiometric sensor of ALP activity displays a linear detection range from 0.005 to 15 U L −1 with a detection limit of 0.0018 U L −1 . The sensor was further successfully used for ALP activity detection in human serum with satisfactory results. [ABSTRACT FROM AUTHOR]

[Display omitted] • Can select the sensor molecules for the selective recognition of Cu2+ and Fe3+ ions before their synthesis. • The use of chemicals will be controlled in this approach. • The effect of ortho -substituents or heteroatom must play a vital role in selective recognition process. • The mechanism of metal ion recognition was established via theoretically and spectroscopic methods. Herein we have implemented a computational approach in designing sensor molecules for the selective recognition of Cu2+ and Fe3+ ions. Seven rhodamine B hydrazide-based Schiff base derivatives were designed and analysed their chemosensing properties against Cu2+ and Fe3+ ions in ethanol solution theoretically. The theoretical calculations revealed that the selective recognition of Cu2+ and Fe3+ ions takes place via spirolactam ring-opening and there is a pivotal role of ortho substituents and N -heteroatoms. The two best chemosensors were synthesised and used for the detection of Cu2+ and Fe3+ ions by colorimetric methods. [ABSTRACT FROM AUTHOR]

An electrochemical sensor based on gold nanoparticles (Au NPs) modified with rhodamine B hydrazide (RBH) (AuNPs-RBH) was developed and applied in the highly sensitive and selective detection of Cu 2+ in water. RBH molecules were bounded onto the surface of AuNPs via the strong interaction between the amino groups and Au NPs. The chemical structure variations were characterized by X-ray photoelectron spectroscopy and fluoresence spectroscopy. Additionally, electrochemical impedance spectroscopy was used to determine Cu 2+ ions in an aqueous solution with the developed AuNPs-RBH-based electrochemical sensor. Results show that the fabricated sensor exhibits good electrochemical performance because of the presence of Au NPs and high affinity with the Cu 2+ resulting from the strong coordination chemistry between Cu 2+ and RBH. The as-developed sensor towards detecting Cu 2+ has a detection limitation of 12.5 fM within the concentration range of 0.1 pM–1 nM by using the electrochemical impedance technique. It also displays excellent selectivity, regeneration, stability, and practicability for Cu 2+ detection. Therefore, the new strategy of the RBH-based electrochemical sensor exhibits great potential application in environment treatment and protection. [ABSTRACT FROM AUTHOR]

• Rhodamine B hydrazide was proposed as a new derivatizing reagent for formaldehyde. • A rapid, selective and sensitive HPLC method for residual formaldehyde in a drug was developed and validated. • The proposed method has the advantages of mild derivatization temperature, short derivatization time, and high sensitivity. Rhodamine B hydrazide (RBH) was prepared as a new derivatizing reagent for residual formaldehyde in a drug such as N-butyl-2-cyanoacrylate (NBCA). RBH reacted with formaldehyde rapidly at room temperature, and the resulting derivative can be detected sensitively at 238 nm. After optimizing the derivatization and chromatographic separation conditions, RBH as a pre-column derivatizing reagent has been successfully used for the analysis of formaldehyde in real NBCA samples by high-performance liquid chromatography (HPLC). The detection limit of the method is 0.004 μg/mL for formaldehyde, and the recovery is 94.0%-96.6%. Most notably, compared with the previous HPLC methods, the developed method has the advantages of mild derivatization temperature, short derivatization time and high sensitivity. [ABSTRACT FROM AUTHOR]

In this work, different materials were fabricated from cellulose acetate, loaded with rhodamine B hydrazide and tested as Cu(II) optical sensor. We prepared membranes displaying a sub-micron porous structure using the phase inversion technique, clusters of fibers with varying diameter depending on the preparation procedure using electrospinning, and casted films presenting a smooth non porous structure. Loading of rhodamine B hydrazide on the fabrics after their production was found to be the best procedure to ensure the stability of the dye in the polymeric materials. Absorption and emission analysis of the solid substrates revealed the presence of the dye on the porous fabrics and allowed to choose the most suited materials and loading conditions to test their response towards Cu(II) ions. Reaction of the loaded rhodamine B hydrazide with Cu(II) was confirmed by absorption and emission spectroscopies and by confocal fluorescence imaging, through detection of the product rhodamine B. The results point to promising sensing applications of the prepared composite materials. [ABSTRACT FROM AUTHOR]

Polysulfone‐based materials were fabricated as casted films, porous membranes, and nanofibers by solution casting, phase inversion process, and electrospinning technique, respectively. Photoactive rhodamine B hydrazide molecules were loaded into the fabrics either in preloading or postloading processes. The morphological structure of the fabrics was investigated by scanning electron microscopy and the wettability was determined by contact angle measurements. Detailed spectroscopic characterizations of the closed and open forms of rhodamine B was performed both in solution and in the solid‐state composite materials. Theoretical investigations supported the depiction of the absorption and emission features of the two forms. The response of the prepared composite materials to Cu(II) ions has been tested by absorption and emission spectroscopy and confocal fluorescence imaging. The most effective materials for Cu(II) detection were found to be polysulfone films prepared by phase inversion and postloaded with 10% rhodamine B hydrazide. These results open the way to the development of composite sensory membranes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48408. [ABSTRACT FROM AUTHOR]

A new fluorometric assay is presented for the ultrasensitive quantification of total protein carbonyls, and is based on their specific reaction with rhodamine B hydrazide (RBH), and the production of a protein carbonyl-RBH hydrazone the fluorescence of which (at ex/em 560/585 nm) is greatly enhanced by guanidine-HCl. Compared to the fluorescein-5-thiosemicarbazide (FTC)-based fluorometric assay, the RBH assay uses a 24-fold shorter reaction incubation time (1 h) and at least 1000-fold lower protein quantity (2.5 µg), and produces very reliable data that were verified by extensive standardization experiments. The protein carbonyl group detection sensitivity limit of the RBH assay, based on its standard curve, can be as low as 0.4 pmol, and even lower. Counting the very low protein limit of the RBH assay, its cumulative and functional sensitivity is 8500- and 800-fold higher than the corresponding ones for the FTC assay. Neither heme proteins hemoglobin and cytochrome c nor DNA interfere with the RBH assay., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)