查找使用阿拉丁产品的科研文献

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

Ziwen Zhang,Ran Han,Sixuan Chen,Feilin Zheng,Xinmiao Ma,Mingfei Pan,Shuo Wang

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 × 10−2μM (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.Keywords:Hg2+;R6GH;dual mode;fluorescence;visualization

2D Co3O4 modified by IrO2 nanozyme for convenient detection of aqueous Fe2+ and intercellular H2O2

Yan Zhengquan,Zheng Xiaoyu,Meng Guoqing,Tang Yulian,Zhou Xuemei,Hao Junkai,Feng Jing,Lin Naibo,Hu Lei

A portable sensor for visual monitoring of Fe 2+ and H 2 O 2 , two-dimensional Co 3 O 4 modified by nano-IrO 2 (IrO 2 @2D Co 3 O 4 ) was prepared in this work, for the first time, with the help of microwave radiation at 140 °C, which was further stabilized onto common test strips. The present IrO 2 @2D Co 3 O 4 possessed superior dual-function enzyme-like activity with low toxicity and excellent biocompatibility. Especially, trace Fe 2+ and H 2 O 2 could exclusively alter their enzyme-like catalytic activity with discriminating hyperchromic or hypochromic effect, i.e., from blue to colorless or to dark blue for both IrO 2 @2D Co 3 O 4 dispersion and its functionalized test strips. The linear regression equations were A 652  = 0.5940 − 0.00041 c Fe 2+ (10 −8  M, R 2  = 0.9927) for Fe 2+ and ∆A 652  = 0.0023 c H2O2  + 0.00025 (10 −7  M, R 2  = 0.9982) for H 2 O 2 , respectively. When applied to visual monitoring of aqueous Fe 2+ and intercellular H 2 O 2 , the recoveries were 101.2 ~ 102.5% and 95.8 ~ 103.7% with detection limits of 1.25 × 10 −8  mol/L and 1.02 × 10 −7  mol/L, respectively, far below the permitted values in drinking water set by the World Health Organization. The mechanisms for the enhancing enzyme-mimetic activity of IrO 2 @2D Co 3 O 4 and its selective responses to Fe 2+ and H 2 O 2 were investigated in detail. Graphical Abstract

A Novel Synthesis Method of Dumbbell-like (Gd1−xTbx)2O(CO3)2·H2O Phosphor for Latent Fingerprint

Lei Huang,Jian Qian,Shijian Sun,Zheng Li,Dechuan Li

A novel method for synthesizing dumbbell-shaped (Gd1−xTbx)2O(CO3)2·H2O (GOC:xTb3+) phosphors using sodium carbonate was investigated. An amount of 1 mmol of stable fluorescent powder can be widely prepared using 3–11 mmol of Na2CO3at a pH value of 8.5–10.5 in the reaction solution. The optimal reaction conditions for the phosphors were determined to be 7 mmol for the amount of sodium carbonate and a pH of 9.5 in the solution. Mapping analysis of the elements confirmed uniform distribution of Gd3+and Tb3+elements in GOC:xTb3+. The analysis of fluorescence intensity shows that an optimal excitation wavelength of 273 nm is observed when the concentration of Tb3+is between 0.005 and 0.3. The highest emission intensity was observed for GOC:0.05Tb3+with a 57.5% maximum quantum efficiency. The chromaticity coordinates show that the color of GOC:Tb3+is stable and suitable for fluorescence recognition. Latent fingerprint visualization reveals distinctive features like whorls, hooks, and bifurcations. Therefore, the sodium carbonate method offers an effective alternative to traditional urea chemical reaction conditions for preparing GOC:Tb3+.

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A Visually Observable Copper Ion Adsorption Membrane by Electrospinning Combined with Copper Ion Probe

Zhang Hongnan,Yao Chenchen,Qin Xiaohong

Heavy metal copper ion pollution has enormously threatened ecosystem and public health. So, materials for detecting and adsorbing copper ions (Cu 2+ ) still remains challenging. Electrospinning nanomaterials have good application prospects in the field of water treatment because of its high specific surface area, high porosity and three-dimensional structure. Here, a visualized chitosan/polyacrylonitrile (CS/PAN) nanofiber membrane (NFM) was prepared via the amination modification of the electrospinning membrane and the doping of Cu 2+ fluorescent probe to adsorb Cu 2+ . The effect of membrane absorbs Cu 2+ in water was studied from the aspects of initial Cu 2+ concentration, PH and adsorption time. It was found that when the pH value of the Cu 2+ environment is 5–6, the weight gain rate of aminated nanofiber membrane is 46 %, and the adsorption time is 90 minutes, the adsorption capacity of the NFM can reach 164.3 mg/g. Then, rhodamine hydrazide derivatives were used as fluorescent Cu 2+ probes, which were added to the spinning solution to prepare new NFM to achieve selective recognition of Cu 2+ . The membrane can be used multiple times and can achieve gradient color development of different concentrations of Cu 2+ , and the detection limit can reach 10 −8 M.

Visual detection of Fusarium temperatum by using CRISPR-Cas12a empowered LAMP assay coupled with AuNPs-based colorimetric reaction

Yingchun Li,Yaqin Zhang,Fange Kong,Chunxia Wang,Shanshan Chen,Jiasi Wang,Di Wang

Fusarium temperatum ( F. temperatum ) causes maize stalk rot disease, reducing grain yield and producing multiple harmful mycotoxins that threaten food safety and quality. However, current detection methods are limited by the requirement of well-trained personnel, complicated operations and expensive instruments. To address this challenge, gold nanoparticles (AuNPs)-based colorimetric assay using loop-mediated isothermal amplification (LAMP) coupled with CRISPR-Cas12a (Au-CRISPR) was tested for F. temperatum detection. The assay utilizes DNA-modified AuNPs as a colorimetric probe and the results can be readily observed by the naked eye. After optimization, the method can specifically detect as low as 100 copies/μL of target DNA or 10 −8  ng/μL of extracted DNA from F. temperatum . The detection platform allows high-throughput testing by integrating microtiter plates and microplate reader. Furthermore, a portable smartphone-based device was developed to realize point of care (POC) detection of F. temperatum in resource-limited settings. This simple, inexpensive and sensitive detection platform has great potential for the applications in field detection.

Selenium Hydride-Induced Oxidase-like Activity Inhibition of Amorphous/Crystalline Manganese Dioxide: Colorimetric Assay for Selenium Detection

Bodong Wang,Shan Pu,Bingxin Ma,Xingyan Zou,Qing Xiong,Xiandeng Hou,Kailai Xu

Hydride generation-based optical sensors have achieved on-site visual selenium (Se) determination with high anti-interference capability, yet they rely on the change of single-color intensity with a narrow linear dynamic range. Herein, we combined selenium hydride (H2Se)-induced activity inhibition of a manganese dioxide (MnO2) nanozyme with different degrees of 3,3′,5,5′-tetramethylbenzidine (TMB) oxidation to realize sensitive multicolor visual detection of Se(IV). Due to its high oxidase-like (OXD-like) activity and sensitive response to H2Se, amorphous/crystalline manganese dioxide (ac-MnO2) was selected to form the headspace single droplet for microextraction and recognition. Via headspace redox reaction with H2Se, ac-MnO2 was reduced into low valence accompanied by in situ generation of Se nanoparticles, leading to the formation of a Se-MnOx aggregate. The experimental results and theoretical calculation indicated that, compared with MnO2, Se-MnOx had decreased active sites for adsorbing O2 to generate •O2–, resulting in the nanozyme activity inhibition that was totally dependent on Se(IV) concentration. The implementation of this strategy enabled accurate Se(IV) detection with a linear range from 10 to 600 μg L–1 and a limit of detection of 1.8 μg L–1. The portable smartphone-based detection for real sample analysis further demonstrated that this assay can be an easy, convenient, and intelligent tool for on-site selenium determination.

Intelligent detection of tetracycline by a rare earth multicolor fluorescent probe based on guanosine-5′-monophosphate

Yingjie Yuan,Xiangzhen Chen,Lei Jia,Yongxin Li,Dan Zhao,Lina Zhang,Yuanyuan Huang,Jun Xu,Tongqian Zhao

Long-term discharge of tetracycline (TC) in the environment exerts selective pressure on the bacteria, increasing resistance in sensitive bacteria and posing a serious threat to public health. Therefore, it is crucial to develop real-time detection of tetracycline. In this study, we reported a novel rare-earth fluorescent nanosensor FITC-GMP-Eu, based on the formation of guanosine-5′-monophosphate disodium salt (GMP) and fluorescein isothiocyanate (FITC), which enabled the real-time identification of tetracycline in the environment. When there was no TC in the environmental sample, the FITC-GMP-Eu nanosensor exhibited the green fluorescence of FITC due to the fluorescence quenching effect of water molecules on Eu 3+ . When the environmental samples contained TC, the red fluorescence of Eu 3+ could be sensitized due to the diketone structure in the tetracycline molecule, which enabled the naked-eye visualized identification of TC. The nanosensor had high sensitivity (detection limit of 19 nM) and a wide detection range (0–30 μM) for TC. At the same time, the sensor was characterized by high visualization and anti-interference ability due to the strong fluorescence of both FITC and Eu complexes. In order to improve the practicality of the detection, this study also prepared a paper-based and sodium alginate gelated fluorescence detection platform with low background fluorescence. Combined with the common color analysis and RGB extraction procedures in mobile phones, real-time and on-site identification of TC on the surface of various fruit samples can be achieved.

Visual detection of folic acid based on silica coated CdTeS quantum dots in serum samples

Min Yang,Cunjin Wang,Yujia Yan,Enzhou Liu,Xiaoyun Hu,Hong Hao,Jun Fan

Currently, folic acid (FA) has been used as an effective biomarker for early diagnosis of many diseases, so it is of practical significance to explore an ideal material with excellent performance for sensing FA. Herein, a visual fluorescent probe was creatively designed by wrapping silica shell (SiO 2 ) on the surface of CdTeS quantum dots (CdTeS QDs@SiO 2 ). The color change of the samples could be easily recognized by the naked eyes and was analyzed based on the red, green and blue (RGB) values obtained using ImageJ software. A good linear relationship was fitted between the ratios of F 445 /F 680 and FA concentrations ranging from 5 to 80 μM (R 2 =0.992) with a limit of detection (LOD) of 0.30 μM. Additionally, the proposed fluorescent probe was applied to detect FA in serum samples with satisfactory results obtained and exhibited a great potential for the quantification of FA in clinical medicine.

A Sensitive and Selective Method for Visual Chronometric Detection of Copper(II) Ions Using Clock Reaction

Yue YALING,He YI

We report a visual chronometric method for the detection of copper(II) ions (Cu2+) using the clock reaction between methylene blue (MB) and hydrazine (N2H4). The addition of Cu2+ greatly accelerates the clock reaction due to the formation of the Cu cluster between Cu2+ and N2H4. By recording the change of the reaction time and solution color, different concentrations of Cu2+ in buffer and environmental water have been detected. As low as 300 nM Cu2+ can be visually identified by the naked eye without the assistance of any advanced instruments. This visual chronometric assay shows a dynamic range from 0.2 to 16 μM with a limit of detection of 20 nM. Additionally, it has good selectivity toward Cu2+ and against other common metal cations.

Quadratic recycling amplification for label-free and sensitive visual detection of HIV DNA

Wenjiao Zhou,Xue Gong,Yun Xiang,Ruo Yuan,Yaqin Chai

Visual detections have attracted great research attentions recently due to their convenient monitoring of the target analytes without using any advanced instruments. However, achieving visual detection of trace amounts of biomolecules with PCR-like sensitivity remains a major challenge. In current work, we describe a new quadratic signal amplification strategy for sensitive visual detection of HIV DNA biomarkers based on exonuclease III (Exo III)-assisted DNA recycling amplification and DNAzymes. The presence of the target HIV DNA leads to two independent and simultaneous DNA recycling processes to achieve quadratic signal amplification with the assistance of Exo III. This quadratic signal amplification results in catalytic cleavage of the G-quadruplex sequence-locked hairpin probes to release numerous active G-quadruplex sequences, which further associate with hemin to form DNAzymes and cause significantly intensified color change for sensitive and visual detection of HIV DNA down to 2.5   pM. The proposed visual detection method employs un-modified hairpin DNA as probes, avoids using any complex and expensive instruments for signal transduction and is essentially simple. This method also shows single-base mismatch discrimination capability as well. All these features make our developed DNA detection method holds great potential for visual monitoring of various DNA biomarkers at ultralow levels with careful and proper probe designs.

A novel agar gel-based colorimetric test tube for visual detection of nitrite in pickled mustards

Xiaoqi Weng,Jing Zhang,Yunxuan Duan,Jing Chen,Yuanting Zhu,Chen Xiao,Yong Zuo

In the present work, a new strategy for visual detection of nitrite in pickled mustards based on the principle of diazotization coupling reaction was proposed. Under acidic conditions, nitrite could induce the formation of the purplish red compound by reacting with sulfanilamide and N-ethylenediamine (NETH). The Euclidean distance (ED) presented a good linear relationship with nitrite concentration from 0.1 to 15 μg/mL (R 2 = 0.976). Additionally, the agar gel-based colorimetric test tube was further developed by combining the agar and reaction regents. The linear range of detection of colorimetric test tube for nitrite were 0.1–3 μL/mL and 5–20 μL/mL, respectively, demonstrating good quantitative analysis ability. The agar gel-based colorimetric test tube presented great selectivity and anti-interfering properties towards nitrite and was successfully applied for the detection of nitrite in different pickled mustards, demonstrating great practical application prospects. The proposed agar gel-based colorimetric test tube exhibits the advantages of simple preparation, convenient to carry, easy operation, fast reaction and data visualization, is beneficial for the real-time and on-site detection of nitrite, and is helpful for the food safety supervision of pickled mustards.