ANALYTICAL BIOCHEMISTRY
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2020
·
IF 2.877
Xiaodong Cao,Zihao Xia,Wuwen Yan,Shudong He,Xuan Xu,Zhaojun Wei,Yongkang Ye,Haisong Zheng
In this paper, we present a simple and label-free colorimetric biosensor for detection of the nopaline synthase (NOS) terminator in genetically modified (GM) plants. The “signal on” colorimetric biosensor was developed using a nanocomposite consisted of gold nanoparticles doped magnetic Fe 3 O 4 nanoparticles (Fe 3 O 4 @Au NP), capture probe DNA (cDNA), and hemin-functionalized reduced graphene oxide nanosheets (H-GN). The nanocomposite was successfully prepared by means of Au–S bonds and the strong π interactions between cDNA and H-GN. The sensing approach is based on the excellent peroxidase-mimicking activity of H-GN and its different electrostatic interactions with single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA). In presence of the target NOS, the cDNA in the nanocomposite will hybridize with its complementary sequence, and form dsDNA structure. Due to the weak π interactions between dsDNA and H-GN, a portion of H-GN will be released from the surface of Fe 3 O 4 @Au NPs and transferred into solution. After magnetic separation was performed, the supernatant was incubated with 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H 2 O 2 . The released H-GN can catalyze the oxidation reaction of TMB and turn the colorless solution blue. This “signal-on” colorimetric biosensor shows a broad linear range of 0.5–100 nM for the target NOS, with a 0.19 nM detection limit. The application of the biosensor for determination of NOS segments in samples of GM and non-GM tomatoes shows that it can discriminate between GM and non-GM plants. The reliability of the method for samples of NOS-spiked GM tomato suggests satisfactory recoveries in the range of 93.6%–94.2%.
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Nanoscale
·
2024
·Vol. 16
·期 29
·13938-13944
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IF 5.8
Dan Xie,Youyou Deng,Xunlong Ji,Yiyan Zhang,Wentao Zhang,Zijin Hong,Wenjing Liu,Jingjing Du,Zhenli Sun
A novel breakthrough has been achieved in gas detection through the innovative application of surface-enhanced Raman scattering (SERS) to hydrogen (H2) detection for the first time. This study capitalizes on the unique SERS effects of gold nanoparticles coupled with the redox interaction between hydrogen and crystal violet, allowing for the development of a magnetic SERS probe that demonstrated enhanced sensitivity and specificity. This new probe can detect hydrogen concentrations as low as 1% by volume in gaseous environments, offering a substantial improvement over the detection limits of traditional hydrogen alarms. Further, this report comprehensively detailed the synthesis of the FA-CV materials, instrumental analysis, and an in-depth evaluation of the SERS performance of the FA-CV substrate, underlining the outstanding sensitivity, stability, and recyclability of the probe. The introduction of SERS in this novel capacity not only contributes a valuable approach to gas sensing technologies, but also suggests promising avenues for the application of SERS in environmental monitoring and energy security. This illustrates the adaptability and potential impact of this powerful technique.
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TALANTA
·
2020
·
IF 5.339
Ting Zhang,Lingli Lei,Meiling Tian,Junjie Ren,Zhisong Lu,Yang Liu,Yingshuai Liu
An ultrasensitive lateral flow immunoassay (LFIA) strip has been developed based on a multifunctional photothermal contrast Fe 3 O 4 @Au supraparticle (Fe 3 O 4 @Au SP) for quantitative Ochratoxin A (OTA) detection. The Fe 3 O 4 @Au SP composite not only shows a better photothermal effect over Fe 3 O 4 and gold nanoparticles , but possesses magnetic property and excellent ability to directly adsorb protein (antibody). Under 808 nm irradiation, photothermal images of the test strips are recorded by a portable Infrared thermal camera. A quantitative analysis is easily achieved based on the thermal changes, which are proportional to the concentrations of analytes. Under an optimal condition, a wide linear detection range from 1 pg mL⁻ 1 to 1μgmL⁻ 1 and a limit of detection (LOD) at 0.12 pg mL⁻ 1 have been achieved with OTA as a model analytes. The practical application potential has also been validated by detection of OTA in spiked corn , peanut, and soybean extractives with overall recoveries ranging from 98.6% to 115% and coefficient of variations (CVs) between 6.06% and 12.73%. The photothermal LFIA renders a rapid, sensitive, and quantitative bio-/chemo-sensing platform with only a portable laser source and a thermal camera.
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ANALYTICA CHIMICA ACTA
·
2020
·
IF 5.977
Ting Zhou,Min Fan,Ruiyun You,Yudong Lu,Luqiang Huang,Yunchao Xu,Shangyuan Feng,Yang Wu,Huiying Shen,Lanjin Zhu
We have successfully prepared a highly sensitive sandwich nanosensor combined Fe 3 O 4 and [email protected] @Ag nanorods for histamine detection based on surface-enhanced Raman spectroscopy (SERS). The Fe 3 O 4 beads with –COOH served as a capture part to enrich histamine. The [email protected] @Ag core-shell nanorods functionalized with Nalpha,Nalpha-Bis(carboxymethyl)- l -lysine (AB-NTA) were then used to connect with the imidazolyl group of histamine, simultaneously the internal standard 4-aminothiophenol (4-ATP) in the core-shell structure was used as the SERS signal. PLS regression model based on concentration range 10 −3 -10 −8 mol/L showed a linear trend with R 2 = 0.9907. Our new approach can quickly and reliably determine histamine in fish sample and RAW264.7 cell lysates. This protocol for histamine extraction and SERS analysis enables the development of ultra-sensitive method for histamine detection.
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ACS Applied Materials & Interfaces
·
2017
·
IF 7.504
Peng Miao,Yuguo Tang,Lei Wang
Driven by the urgent need to detect trace heavy metal ions in various real water samples, this article demonstrates for the first time an electrochemical biosensor based on DNA modified Fe3O4@Au magnetic nanoparticles (NPs). Three DNA probes are designed to contain certain mismatched base pairs. One is thiolated and modified on the surface of Fe3O4@Au NPs (DNA 1). The other two probes (DNA 2 and 3) are labeled with two independent electrochemical species. Stable structures of cytosine–Ag+–cytosine and thymine–Hg2+–thymine formed in the presence of Ag+ and Hg2+ can assist the hybridization of DNA 1/DNA 2 and DNA 1/DNA 3, which locate corresponding electrochemical species onto the surface of the magnetic NPs. The achieved nanocomposites are then used as selective electrochemical probes for the detection of heavy metal ions by recording the square wave voltammetry signals. Simultaneous detection of Ag+ and Hg2+ is demonstrated without significant interference, and their individual high sensitivities are fundamentally preserved, which meet the requirements of U.S. Environmental Protection Agency (USEPA). Furthermore, the proposed method has been challenged by various real water samples. The results confirm the DNA modified magnetic NPs based sensing method may have potential applications for the monitoring of heavy metal ions in real sample analysis.
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ELECTROANALYSIS
·
2017
·Vol. 29
·期 9
·2098-2105
·
IF 2.851
Fang Shang,Yuan Liu,Sui Wang,Yufang Hu,Zhiyong Guo
An ultrasensitive electrochemiluminescence (ECL) immunosensor for the detection of tetrodotoxin (TTX) is proposed, which are composed of the branched poly-(ethylenimine) (BPEI) functionalized graphene (BGNs)/Fe 3 O 4 -Au magnetic capture probes and luminol-capped gold nanocomposites (luminol-AuNPs) as the signal tag. Herein, a typical sandwich immunecomplex was constructed on the glassy carbon electrode. The BGNs/Fe 3 O 4 -Au hybrids could efficiently conjugate primary antibody via the Au−S chemical bonds or Au−N chemical bonds and rapidly separate under external magnetic field. The introduction of BPEI to GO could enhance the luminol-ECL intensity. Meanwhile, the multifunctional nanocomposites have been proved with good water-solubility, excellent electron transfer, outstanding stability, etc. The luminescent luminol-AuNPs, a high efficient electrochemiluminescence marker, can be assembled on the second antibody, which can produce the ECL signal to achieve the determination of TTX. This proposed ECL immunosensor with a linear range from 0.01–100 ng/mL can be applied in the detection of TTX in real samples with satisfactory results.
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CERAMICS INTERNATIONAL
·
2017
·
IF 2.986
Xiaolin Liu,Yongxin Tao,Huihui Mao,Yong Kong,Jian Shen,Linhong Deng,Linsong Yang
Near-infrared (NIR) light has great potential in biomedical applications due to its advantages of deep penetration depth and low photodamage to biological tissues. In this paper, we constructed a novel core-shell structured drug nanocarrier, Fe 3 O 4 @Au@SiO 2 , for the controlled delivery of etoposide (VP16), a chemotherapeutic drug for cancer patients. The novel core-shell structured drug delivery platform is composed of a mesoporous silica shell and a magnetic Fe 3 O 4 core using Au nanoparticles (AuNPs) as the interlayer, which is characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, N 2 adsorption/desorption isotherms and the magnetic measurements with vibrating-sample magnetometer (VSM). The synergistic effects of AuNPs, mesoporous silica and Fe 3 O 4 make the core-shell structured nanocomposites an excellent candidate for targeted and NIR light irradiation-controlled drug delivery. For the proposed nanocarrier of VP16, the mesopores in silica can enhance the encapsulation capacity of the nanocarrier and the AuNPs can effectively convert the NIR light into heat to speed up the drug deliver; meanwhile, the incorporation of Fe 3 O 4 with high magnetization to the drug delivery platform realize drug targeting under an applied external magnetic field.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2024
·
IF 8.2
Lin Zhu,Wei Zeng,Yueqing Li,Yu Han,Jing Wei,Long Wu
In this work, on the basis of Fe 3 O 4 @Au-Pt nanozymes (MAP NZs) and aptamer recognition, a magnetic fluorescent aptasensor (MFA) was developed for sensitive and accurate detection of saxitoxin (STX). With the bridge of STX aptamer (Apt STX ) and complementary DNA (cDNA), Apt STX decorated MAP NZs (MAP/Apt) and cDNA modified green quantum dots (cDNA@g-QDs) were connected to form MAP/Apt-cDNA@g-QDs complex. As STX behaves a strong binding ability towards Apt STX , it will compete with cDNA and hybridize with Apt to release cDNA@g-QDs. With the addition of TMB, MAP will catalyze TMB to the oxidized TMB (ox-TMB), thereby quenching the fluorescence of g-QDs due to the inner filter effect. Based on this finding, the quantitative relationship between the change in fluorescence of gQDs and STX concentration was explored with a limit of detection (LOD, S/N = 3) of 0.6 nM. An internal standard signal of oxTMB was adopted and reduced the fluctuation of fluorescence signal output. Besides, the fluorescence probe can selectively recognize and detect STX among five marine toxins. Eventually, the MFA method behaved good performance in detecting seafood samples with recoveries of 82.0 % ∼ 102.6 % as well as coefficient of variations (CV) of 7.2 % ∼ 10.3 %. Therefore, the method with internal signal is hopeful to be a potential candidate for sensitive and accurate detection of STX in seafood.
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MICROCHEMICAL JOURNAL
·
2025
·
IF 5.1
Fang Li,Pengying Zhang,Jiayi Chen,Jiahui Xi,Shuai Gao,Yunhong Liu
Mercury ion (Hg 2+ ), a highly toxic and bioaccumulative pollutant, can contaminate medicinal herbs and pose significant risks to human health via the food chain. With the growing global demand for traditional Chinese medicine (TCM), there is an urgent need to develop reliable and sensitive Hg 2+ detection methods. In this paper, a novel electrochemical sensor based on magnetic nanoparticles and thymine-Hg 2+ -thymine (T-Hg 2+ -T) coordination chemistry was developed for detecting Hg 2+ in TCM. The magnetic Fe 3 O 4 /Au nanoparticles (Fe 3 O 4 /Au NPs) were synthesized and employed as carriers to conjugate with T-rich thiol-modified DNA probes. In the absence of Hg 2+ , the DNA probes hybridized with ferrocene (Fc)-labeled complementary DNA (cDNA), bringing the Fc signal molecules close to the Fe 3 O 4 /Au NPs surface. In the presence of Hg 2+ , these probes preferentially formed stable T-Hg 2+ -T complexes, effectively inhibiting cDNA hybridization. The Hg 2+ concentration was determined by measuring the corresponding changes in the Fc current. The sensor exhibited a good linear response to Hg 2+ in the range of 0.1–100 ng/mL, with a low detection limit of 0.08 ng/mL. Furthermore, the method was successfully applied to determine Hg 2+ in representative TCM matrices (Lotus leaf, Lonicera japonica , Angelica dahurica , and Houttuynia cordata Thunb.) with satisfactory recoveries (96.73 %−104.84 %). This indicates that the proposed method is particularly suitable for Hg 2+ determination in complex TCM samples, providing a practical solution for quality control and safety monitoring in TCM.
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FOOD CHEMISTRY
·
2020
·
IF 6.306
Huirong He,Da-Wen Sun,Hongbin Pu,Lunjie Huang
Aflatoxin B1 (AFB1) as the most toxic mycotoxin in contaminated food can greatly threaten human health, and sensitive and selective detection of AFB1 is thus highly desired. An ultrasensitive surface-enhanced Raman spectroscopy (SERS) aptasensor was developed for AFB1 detection in peanut oil samples. SH-cDNA modified Fe 3 O 4 @Au nanoflowers acted as capture probes, SH-Apt modified [email protected] nanospheres and commercial Cy3-Apt were used as reporter probes. Strong SERS signals of reporter probes were produced due to the recognition of AFB1 aptamer and its complementary strand (SH-cDNA). With the preferred binding of AFB1 aptamer to AFB1, reporter probes were released from capture probes, causing a linear decrease in SERS intensity. Therefore an ultralow detection limit of 0.40 pg·mL −1 in a wide linear range of 0.0001–100 ng·mL −1 was obtained and the sensibility of this SERS aptasensor was higher than that of the Cy3-Apt based SERS aptasensor. In addition, an excellent selectivity in interfering toxins and satisfactory recoveries of 96.6–115% in peanut oil samples were obtained, proving this aptasensor is a promising analytical tool in AFB1 detection.
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ANALYTICAL CHEMISTRY
·
2018
·
IF 6.042
Na Li,Ting Zhong,Jia-liang Liu,Jun Zheng,Hu-cheng Deng,Wen Zhou,Ming Li,Ming-shi Feng,Qi-jun Liu,Chong-ying Li
Analysis and characterization of micro/nano-sized pore structure are critical issues in shale geology and engineering. Scanning electron microscopy (SEM) imaging is one of the most widespread methods for the analysis of the micro/nano-sized pores in shale, but precise identification of the ultrafine pore structure in shale is still a big challenge because shale is so complex that some components may have overlap with pores based on the simple discrimination of gray scale under SEM microscopy. Here, Fe3O4/Au nanocomposite with magnetic properties is synthesized, characterized, and introduced as a novel pore-marker to improve SEM identification and quantitation of micro/nano-sized pores in shale. Due to the superparamagnetic property, the nanomarker is conveniently controlled by an external magnetic field to fill into pores and offers a sharp contrast imaging between matrix of shale (various gray) and pores (bright), which makes the identification of micro/nano-sized pores in shale much more straightforward and reliable. Furthermore, because gold, as a noble metal, is particularly rare in shale, energy-dispersive X-ray spectroscopy mapping of Au is delicately used to precisely calculate area porosity in shale. Combining with the aforementioned merits of the nanomarker, a precise and practical technique is proposed to promote characterization of micro/nano-sized pores in shale.
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BIOSENSORS & BIOELECTRONICS
·
2015
·
IF 6.409
Qing Han,Xin Shen,Wanying Zhu,Chunhong Zhu,Xuemin Zhou,Huijun Jiang
A novel magnetic molecularly imprinted sensing film (MMISF) was fabricated for the determination of estradiol (E2) based on magnetic glassy carbon electrode (MGCE) and magnetic molecularly imprinted polymers (MMIPs). The MMIPs were synthesized by in situ polymerization of glutathione (GSH)-functionalized gold (Au)-coated Fe 3 O 4 (Fe 3 O 4 @Au-GSH) nanocomposites and aniline. The MMISF was constructed with MMIPs via a kind of “soft modification” where MMIPs were assembled and immobilized on the surface of MGCE or removed from it by freely installing a magnet into MGCE or not. The E2-MMIPs were obtained by MMIPs recognizing E2 from sample, and the electrochemical detection was carried out after forming the “soft modification” sensing film by putting MGCE into the E2-MMIPs suspension liquid. Afterwards, the “soft modification” MMISF was peeled off from the electrode by removing the magnet from MGCE. The interface of the electrode could be quickly refreshed through simple treatment for the next detection. The structures and morphologies of Fe 3 O 4 @Au-GSH, MMIPs and MMISF were investigated by Fourier transform infrared spectrometer, ultraviolet and visible spectrophotometer, scanning electron microscope and atomic force microscope . In addition, the MMISF was successfully used for detecting E2 in milk powder with good sensitivity, selectivity, reproducibility and efficiency. The linear range of the MMISF for E2 was 0.025–10.0 μmol L −1 with the limit of detection of 2.76 nmol L −1 ( S / N = 3).
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