ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2015
·Vol. 407
·期 20
·6031-6039
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IF 3.436
Li Dan,Zhu Qingxia,Lv Diya,Zheng Binxing,Liu Yanhua,Chai Yifeng,Lu Feng
By using a silver nanoparticle wiper as a surface-enhanced Raman scattering substrate, a highly sensitive, convenient, and rapid platform for detecting dye adulteration of medicinal herbs was obtained. Commercially available filter paper was functionalized with silver nanoparticles to transform it into the flexible wiper. This device was found to collect dye molecules with unprecedented ease. Experiments were performed to optimize various factors such as the type of wiper used, the wetting reagent, and the wetting/wiping mode and time. Excellent wiper performance was observed in the detection of the simulated adulteration of samples with dyes at various concentrations. The limits of detection for nine dyes, including 10 −6 g/mL for malachite green, 10 −7 g/mL for Rhodamine 6G, and 5 × 10 −8 g/mL for methylene blue, were discerned. The results of this investigation show that this proposed method is potentially highly advantageous for field-based applications.
Schematic diagram illustrating the fabrication of the paper-based SERS substrate, sample collection process on a herb and SERS examination with the portable Raman spectrometer
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JOURNAL OF SEPARATION SCIENCE
·
2013
·
IF 2.591
Jiangmei Li,Haiyun Zhai,Zuanguang Chen,Qing Zhou,Zhenping Liu,Zihao Su
A novel method combining molecular imprinting and SPE was developed in a capillary column for the determination of auramine O in shrimp. The capillary monolithic column was prepared by UV-initiated in situ polymerization, using auramine O as template and methacrylic acid and ethylene dimethacrylate as functional monomer and cross-linker, respectively. The properties of the prepared capillary monolithic column were investigated under the optimized conditions coupled with HPLC, and then the morphologies of the inner polymers were characterized by SEM. The calibration curve was expressed as A = 103 C + 19.8 ( r = 0.9992) with a linear range of 0.25–25.0 μg/mL, and the recoveries of auramine O at different concentrations in shrimp ranged from 90.5 to 92.4% with RSDs ranging from 2.1 to 4.4%. The capacities of the molecularly imprinted polymer and nonimprinted polymer columns were 0.722 and 0.147 μg/mg, respectively, and the LOD (S/N = 3) of auramine O in shrimp was 17.85 μg/kg. Under the selected conditions, the enrichment factors obtained were higher than 70-fold. The results indicate that the prepared molecularly imprinted capillary monolithic column was reliable and applicable to the analysis of auramine O in shrimp.
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LASER PHYSICS LETTERS
·
2018
·Vol. 15
·期 5
·055701
·
IF 2.235
Xi Liu,Meizhen Huang,Jie Chen,Lili Kong,Keihui Wang
A simple method, based on a roll-to-roll ultraviolet micro-pyramid imprinting technique and a nanoparticle self-assembling process in aqueous solution, to fabricate a large-area, flexible surface-enhanced Raman scattering (SERS) polyethylene glycol terephthalate substrate is proposed. The SERS substrate is demonstrated to be of high sensitivity. The detection concentration of Rhodamine 6G (R6G) measured by a portable Raman spectrometer is down to 10−9 mol l−1. The relative standard deviation values of different spots and different substrates are less than 13%. In addition, the feasibility for rapid detection of dye in herbal tea based on this SERS substrate and a portable Raman spectrometer is investigated. Three industrial dyes are employed to simulate the dyeing process. It is presented that R6G of 4.8\times {{10}^{-7}} g ml−1, malachite green of 10−6 g ml−1 and Auramine O of 10−6 g ml−1 in herbal tea could be detected rapidly. The experimental results imply that this method could be potentially applied in the field of dyed herbal tea detection.
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FOOD CHEMISTRY
·
2024
·
IF 8.5
Maohua Yang,Liangli Li,Chunni Zhao,Mei Zhang,Mingyan Jia
Benzylisoquinoline alkaloids are significant phyto-nutraceuticals with a bitter flavor. However, due to their complex structures, the sensing and identification of benzylisoquinoline alkaloids is challenging. Benzylisoquinoline alkaloids are commonly extracted from plants such as Coptidis Rhizoma (CR), while the adulteration and dyeing of CR are prevalent. Herein, we innovatively developed a colorimetric sensor array based on the inhibitory effect of alkaloids on urease to identify benzylisoquinoline alkaloids and CR. Urea and pH indicators are used to convert the inhibitory effect of alkaloids on urease into visible signals. Different benzylisoquinoline alkaloids have different inhibition abilities to urease, resulting in their own unique colorimetric response pattern. Combined with linear discriminant analysis (LDA), the colorimetric sensor array has successfully identified different types and concentrations of benzylisoquinoline alkaloids, as well as benzylisoquinoline alkaloid mixtures. The array was further employed to identify CR, encompassing its authenticity, variety, adulteration, and dyeing.
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Synthetic and Systems Biotechnology
·
2025
·
IF 4.4
Po Li,Xueying Lei,Xiaoying Niu,Wen Tian,Zhehuang Li,Songcheng Yu,Peng Zhang
MicroRNA (miRNA) is promising candidate for non-invasive diagnostic biomarker. Conventional CRISPR/Cas12a-based miRNA detection systems are constrained by reliance on reverse transcription, nucleic acid pre-amplification and costly fluorescently labeled reporters which introduce chemical modification complexity and background noise. To address these limitations, we herein developed a multifunctional switch that integrated target recognition, CRISPR/Cas12a system activation, intrinsic fluorescence signaling, and autonomous signal amplification within a single molecular architecture. As a proof of concept, this switch enabled a label-free CRISPR/Cas12a biosensing for miR-21 detection with a detection limit of 4.8 nM and robust performance in accuracy, precision, and selectivity. This proposed label-free CRISPR/Cas12a platform could be applied for real sample and is a promising candidate for point-of-care miRNA detection.
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Synthetic and Systems Biotechnology
·
2025
·
IF 4.4
Wen Tian,Songcheng Yu,Kaiyang Zhang,Tao Liu,Lihua Ding,Peng Zhang
The CRISPR/Cas12a system holds significant promise for biomedical applications. Nevertheless, the commonly used reporter, fluorophore–quencher-labeled substrates, is hindered by labor-intensive synthesis procedures and high costs, while also relying on a single-photon method and being vulnerable to environmental interference. Herein, a label-free dual-fluorescent functional nucleic acid (DFFNA) was engineered, comprising an aptamer domain for auramine O (AO) recognition and a dSpacer-integrated DNA duplex region for 5,6,7-trimethyl-1,8-naphthyridin-2-amine (ATMND) binding. The fluorescence of AO and ATMND can be enhanced and quenched, respectively, when bound to DFFNAs. The fluorescence intensity ratio between ATMND and AO increased significantly following the cleavage of DFFNAs by activated Cas12a, thus offering a universal, label-free, ratiometric fluorescent reporter for the CRISPR/Cas12a system. To explore the application of the DFFNA-based CRISPR/Cas12a system, a novel biosensor was developed to detect site-specific DNA methylation. It employs a methylation-sensitive restriction enzyme to recognize methylation sites, Cas12a for site-specific DNA identification and signal amplification, and DFFNAs to produce ratiometric fluorescence. The assay demonstrated remarkable specificity and sensitivity, with a limit of detection of 152 pM, due to the high resolution and trans -cleavage activity of Cas12a. The rationally designed and label-free DFFNAs enhance stability, increase flexibility, and reduce cost. The observable color change and smartphone imaging capability facilitate portable, point-of-care testing. Specifically, the biosensor demonstrated excellent specificity by differentiating colorectal cancer patients from healthy individuals. Consequently, this work presents a superior label-free and ratiometric fluorescent reporter for the CRISPR/Cas12a system, which offers a promising strategy for DNA methylation detection in clinical settings.
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