Journal of Physical Chemistry C
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2012
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IF 4.805
Qiao An,Meng Yu,Yuting Zhang,Wanfu Ma,Jia Guo,Changchun Wang
The heterostructure Ag–Au bimetallic nanocrystals supported on Fe3O4@carbon composite microspheres were synthesized by one facile and controllable approach, wherein the Ag nanocrystals attached on the Fe3O4@carbon microspheres were prepared first and served as reductant for the galvanic replacement reaction with the Au precursor (HAuCl4). Upon varying the feeding amounts of the Au precursor, the bimetallic compositions on the Fe3O4@carbon microsphere could be readily tuned resulting in a series of composite microspheres with different Au-to-Ag molar ratios. Subsequently, we thus investigated the catalytic activity and selectivity of the magnetic composite catalysts from two sides. First, 4-nitrophenol (4-NP) was applied as a model molecule to study the effect of different Au-to-Ag molar ratios on catalytic capabilities of the resulting composite microspheres. It was found that upon the addition of NaBH4 the catalytic capability was markedly enhanced when the Au content was increased. The maximum activity parameter value reached 1580 s–1 g–1, which is far higher than those of known monometallic composites. Also, they could give the equally high yields for other nitroaromatic compounds with various substituents, irrespective of the linked electron-donating or electron-withdrawing groups. Second, the synergistic effects of the carbon substrate in the catalysis reaction were demonstrated. When compared with colloidal SiO2, TiO2, and poly(styrene-co-acrylic acid) substrates, the carbon support not only facilitated the enhancement of the catalytic performance of the noble metal nanocrystals but was also more suitable for the in situ preparation of Au–Ag bimetallic nanocrystals using the GRR. Besides, the particles’ convenience in terms of their magnetic separability and outstanding reusability was validated through many successive reduction reaction cycles. In light of these unique characteristics, the Fe3O4@C@Ag–Au composite microspheres show promising and great potential for practical applications.
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PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2021
·Vol. 23
·期 34
·18930-18935
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IF 3.676
Wei Xiong,Xiang Ren,Binbin Da,Yong Zhang,Hui Zhang,Jianchen Lu,Jinming Cai
Zinc(II) tetraphenylporphyrin (ZnTPP) has very broad application prospects in the fields of supramolecular chemistry, solar cells and nanomaterials. In this paper, by using scanning tunneling microscopy (STM), we systematically investigated the ZnTPP molecule and its four derivatives formed by thermal annealing were characterized unambiguously by bond-resolved STM (BR-STM). The electronic properties of the ZnTPP molecule and its four cyclodehydrogenation products were investigated by scanning tunneling spectroscopy (STS) combined with DFT calculations. The spatial distribution of molecular frontier orbitals of four products was obtained by dI/dV mappings. This work gives rise to a full-scale investigation of ZnTPP on Au(111), which will be potentially useful in nanodevices and optoelectronics.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2025
·
IF 4.6
Xinyu Lan,Guojun Weng,Jianjun Li,Jian Zhu,Junwu Zhao
Surface metal deposition is an important method for tuning the optical property of plasmonic nanoparticles. In this work, we tried to deposit Cu shell on the surface of gold nanorods (Au NRs) by dihydronicotinamide adenine dinucleotide (NADH)-mediated reaction. Cu 2+ were reduced to Cu 0 through the gold-catalyzed oxidization of NADH. The deposition of Cu shell onto the Au NRs surface resulted in the obvious red-shift of longitudinal localized surface plasmon resonance peak. And the red-shift of longitudinal peak increased with the concentrations of NADH and Cu 2+ . The TEM images showed that a transparent layer structure with a different contrast around Au NRs was clearly displayed. And this transparent layer structure with the low contrast was generally considered to be pure Cu shell. However, the results from energy dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS) indicated that the transparent layer was not just pure Cu composition, but contained NADH/NAD + and Cu 2+ components. This grown complex dielectric shell resulted in the reduced surface enhanced Raman scattering (SERS) activity of Au NRs. Based on the decreased SERS intensity, we demonstrated a SERS method for Cu 2+ detection using R6G as Raman reporter. The decreased SERS intensity had a linear correlation with the concentration of Cu 2+ in the range of 10 −6 –10 −2 M, with a detection limit of 3.89 × 10 −6 M. This study provides new insights about Cu deposition on Au NRs, which will further promote the spectral sensing applications with gold-catalyzed Cu 2+ reduction on plasmonic nanoparticles by NADH.
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BIOSENSORS & BIOELECTRONICS
·
2011
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IF 5.361
Yarui An,Xiaoli Jiang,Wenji Bi,Hua Chen,Litong Jin,Shengping Zhang,Chuangui Wang,Wen Zhang
A novel electrochemical immunosensor for sensitive detection of α-synuclein (α-SYN), a very important neuronal protein, has been developed based on dual signal amplification strategy. Herein, G4-polyamidoamine dendrimer-encapsulated Au nanoparticles (PAMAM-Au nanocomposites) were covalently bound on the poly- o -aminobenzoic acid (poly- o -ABA), which was initially electropolymerized on the electrode surface to perform abundant carboxyl groups. The formed immunosensor platform, PAMAM-Au, was proved to provide numerous amino groups to allow highly dense immobilization of antigen, and facilitate the improvement of electrochemical responses as well. Subsequently, the enhanced gold nanoparticle labels ({HRP-Ab 2 -GNPs}) were fabricated by immobilizing horseradish peroxidase-secondary antibody (HRP-Ab 2 ) on the surface of gold nanoparticles (GNPs). After an immunoassay process, the {HRP-Ab 2 -GNPs} labels were introduced onto the electrode surface, and produced an electrocatalytic response by reduction of hydrogen peroxide (H 2 O 2 ) in the presence of enzymatically oxidized thionine . On the basis of the dual signal amplification of PAMAM-Au and {HRP-Ab 2 -GNPs} labels, the designed immunosensor displayed an excellent analytical performance with high sensitivity and stability. This developed strategy was successfully proved as a simple, cost-effective method, and could be easily extended to other protein analysis schemes.
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Advanced Science
·
2023
·Vol. 10
·期 11
·2206979
·
IF 15.1
Si Zheng,Duyang Gao,Yayun Wu,Dehong Hu,Ziyue Li,Yuenan Wang,Hairong Zheng,Yingjia Li,Zonghai Sheng
Radioimmunotherapy (RIT) is an advanced physical therapy used to kill primary cancer cells and inhibit the growth of distant metastatic cancer cells. However, challenges remain because RIT generally has low efficacy and serious side effects, and its effects are difficult to monitor in vivo. This work reports that Au/Ag nanorods (NRs) enhance the effectiveness of RIT against cancer while allowing the therapeutic response to be monitored using activatable photoacoustic (PA) imaging in the second near-infrared region (NIR-II, 1000–1700 nm). The Au/Ag NRs can be etched using high-energy X-ray to release silver ions (Ag + ), which promotes dendritic cell (DC) maturation, enhances T-cell activation and infiltration, and effectively inhibits primary and distant metastatic tumor growth. The survival time of metastatic tumor-bearing mice treated with Au/Ag NR-enhanced RIT is 39 days compared with 23 days in the PBS control group. Furthermore, the surface plasmon absorption intensity at 1040 nm increases fourfold after Ag + are released from the Au/Ag NRs, allowing X-ray activatable NIR-II PA imaging to monitor the RIT response with a high signal-to-background ratio of 24.4. Au/Ag NR-based RIT has minimal side effects and shows great promise for precise cancer RIT.
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Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 40
·23038-23045
·
IF 10.733
Rongrong Pan,Jia Liu,Yuemei Li,Xinyuan Li,Erhuan Zhang,Qiumei Di,Mengyao Su,Jiatao Zhang
Here we show a novel strategy for tailoring the synergistic electrical properties of metal@semiconductor hybrid nanocrystals (HNCs) based on cation exchange-enabled electronic doping. As a demonstration, the conductive nature of Au@CdS core–shell HNCs was changed from n- to p-type by introducing Cu dopants into the CdS shell. The dependence of the conductivity type on the dopant concentration in the HNCs is disclosed by combined photoelectrochemical (PEC) studies. Moreover, a tandem PEC cell consisting of an undoped Au@CdS photoanode and a Cu-doped Au@CdS photocathode respectively modified with cocatalysts is fabricated, which displayed stable H2 and O2 evolution in unassisted PEC overall water splitting.
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CHEMOSPHERE
·
2021
·
IF 7.086
Hangjun Zhang,Yinan Zhang,Yuchi Zhong,Jiafeng Ding
Polychlorinated dibenzo-p-dioxins (PCDDs), characterized by their extreme toxicity, high persistency and bioaccumulation, regard as one of the most concerned environmental pollutants on the priority list. In this study, microwave-hydrothermal and photoreduction methods were adopted for fabrication of ternary Au@Fe/TiO 2 composites for removal of 2,8-dichlorodibenzo-p-dioxin (2,8-DCDD) under UV–Vis light irradiation. The acquired materials were characterized and analyzed by XRD, TEM, XPS, UV–Vis DRS, PL , etc. As a result, the 1%Au@1%Fe/TiO 2 exhibited much higher photocatalytic activity that 96.3% of 2,8-DCDD was removed within 160 min with respect to that of Fe/TiO 2 (3.0 times) and TiO 2 (5.5 times). It revealed the active substances might be produced, which were verified by ESR analysis. In a comparison, the 1%Au@1%Fe/TiO 2 also exhibited high activity in that 97.2% of 2,8-DCDD was removed within 240 min under an anoxic atmosphere. The 1%Au@1%Fe/TiO 2 systems were all pH-dependent that 2,8-DCDD could be fully degraded in neutral conditions. The results of repeatability on 1%Au@1%Fe/TiO 2 showed that the sample was high stability. Fe doping improved the charge separation of TiO 2 and Au modification improved the activity via SPR effect and Mott-Schottky barrier. The degradation mechanisms and pathways were proposed and discussed in detail. The current work develops a new approach on photocatalytic oxidation and reductive dechlorination of dioxins and may open a new opportunity to extend the application range of TiO 2 catalysts.
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FOOD CHEMISTRY
·
2025
·
IF 9.8
Yihao Li,Fengzhen Jin,Bowen Li,Shun Wu,Yuanqing Wang,Yaohui Wu,Yonghong Wang,Ge Ning
Zearalenone (ZEN) is a mycotoxin that exerts multiple toxic effects on humans through the contamination of grains such as corn, posing a significant threat to food safety and human health. This work proposed a dual-signal ratiometric electrochemical aptasensor utilizing ferrocene-carboxylic acid‑gold nanoparticle‑molybdenum disulfide nanosheets (Fc-Au-MoS 2 ), hybridization chain reaction (HCR), and the cleavage effect of DNAzyme triggered by triple-helix molecular switch (THMS) to detect ZEN. The specific interaction with ZEN triggers the release of the DNAzyme from THMS, which then removes the immobilized primer chain on the electrode surface with the assistance of Pb 2+ , thereby preventing HCR occurrence. This inhibitory mechanism reduces methylene blue (MB) insertion while exposing the active sites of Fc-Au-MoS 2 , generating an opposite signal response to achieve high-precision ratio detection. The aptasensor demonstrated a low detection limit of 29.4 pM, with satisfactory recoveries in corn flour (97.3 %–106.4 %), confirming its potential for monitoring mycotoxin residues in food safety.
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APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Yanling Zhang,Min Liu,Shuai Pan,Lulu Yu,Shaoshuai Zhang,Ruijiang Liu
Based on magnetic Fe 3 O 4 /Fe 2 O 3 @Au nanoparticles (Fe 3 O 4 /Fe 2 O 3 @Au NPs), to detect an important tumor screening marker, vascular endothelial growth factor 165 (VEGF 165 ), a label-free electrochemical aptasensor was constructed. Magnetic glassy carbon electrode (MGCE) after Fe 3 O 4 /Fe 2 O 3 @Au NPs surface modification by a magnetic-induced self-assembly technique was the platform. Fe 3 O 4 /Fe 2 O 3 @Au NPs were used as the signal amplifier to enhance electron transfer, which was essential for the detection of trace amounts of biological analytes, and were prepared via heating hydrolyzation-combustion calcination and trisodium citrate reduction. Meanwhile, aptamers bound to the as-prepared nanomaterial via Au-s bonds and specifically recognized VEGF 165. The electrochemical properties of the aptasensor were evaluated with [Fe(CN) 6 ] 3−/4 − as redox probes. When in optimal detection conditions, an excellent linear relationship (between 0.01 and 10 pg mL −1 , R 2 = 0.9973) was obtained for the electrochemical aptasensor. The limit of detection (LOD) and the limit of quantitation (LOQ) of the electrode were 0.01 and 0.03 pg mL −1 . This proposed aptasensor exhibited favourable selectivity, stability, reproducibility, and regenerability. The results demonstrated that the sensor was promising to provide an efficient, accurate, and low-cost auxiliary detection method for the early screening of VEGF 165 -related diseases, which had important clinical practical value for the research of human precision medicine.
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ANALYTICA CHIMICA ACTA
·
2024
·
IF 5.7
Qiuwen Huang,Na Zhou,Jiayi Peng,Xuanjiang Zeng,Lijuan Du,Yan Zhao,Xiaojun Luo
Background The COVID-19 pandemic, caused by the novel coronavirus, has had a profound impact on global health and economies worldwide. This unprecedented crisis has affected individuals, communities, and nations in diverse manners. Developing simple and accurate diagnostic methods is an imperative task for frequent testing to mitigate the spread of the virus. Among these methods, SARS-CoV-2 antigen tests in clinical specimens have emerged as a promising diagnostic method for COVID-19 due to their sensitive and accurate detection of spike (S) protein, which plays a crucial role in viral infection initiation. Results In this work, a dual-signal amplification surface enhanced Raman scattering (SERS)-based S protein biosensor was constructed based on Au NPs/COFs and enzyme-free catalytic hairpin assembly (CHA) amplification method. The approach relies on a released free DNA sequence (T), which is generated from the competition reaction between Aptamer/T and Aptamer/S protein, to trigger a CHA reaction. Due to the high binding affinity and selectivity between the S protein and its aptamer, CHA process was triggered with the maximum SERS tags (H2-conjugated Au@4-mercaptobenzonitrile@Ag) anchored onto Au NPs/COFs substrate surface. This SERS platform could detect the S protein at concentrations with high sensitivity (limit of detection = 3.0 × 10 −16 g/mL), wide detection range (1 × 10 −16 to 1 × 10 −11 g/mL), acceptable reproducibility (relative standard deviation = 7.01 %) and excellent specificity. The biosensor was also employed to detect S protein in artificial human salivas. Significance Thus, this study not only developed a novel Au NPs/COFs substrate exhibiting strong SERS enhancement ability and high reproducibility, but also proposed a promising dual-signal amplification SERS-based diagnostic method for COVID-19, holding immense potential for the detection of a wide range of antigens and infectious diseases in future applications.
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Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Shuai Zhao,Haojia Qin,Jie Huang,Qiang Chen,Shangzhong Jin,Pei Liang
Rapid determination of pesticide residues in water is of vital importance for human health. However, rapid, reliable, and highly sensitive detection of pesticide residues in water environments remains a challenging issue. In this paper, we prepare Fe 3 O 4 /MOF-867 composites using the hot solvent method, and Au + is reduced to Au NPs by the reducing agent and attached to the film of Fe 3 O 4 /MOF-867 composites by the addition of APTES as a linker to synthesize the Au/Fe 3 O 4 /MOF-867 SERS substrates. Then, we change the Fe 3 O 4 content and the concentration of the reducing agent to obtain the optimal substrate. The substrate has a detection capability of up to 10 −9 M for probe molecule R6G and the RSD is less than 5%, which demonstrates that the substrate has excellent SERS effect and reproducibility. In addition, the Au/Fe 3 O 4 /MOF-867 SERS substrates have been applied for the determination of thiram in lake water samples, with its limit of detection (LOD) up to 3.8 × 10 −10 M. The Au/Fe 3 O 4 /MOF-867 SERS substrates can quickly and efficiently collect target analytes by magnetic enrichment, have high SERS performance, and have great potential for the rapid and sensitive detection of pesticide residues and other pollutants in the environment.
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FOOD CHEMISTRY
·
2024
·
IF 8.5
Mengyue Gao,Qiao Chen,ZhiHao Li,YiFang Zhan,LiHua Wang,Ting He,Qi Yao,Fengmei Jin,Jiming Hu
A SPE-SERS method was developed for the detection of several antibiotic residues in dairy products. Gold nanoparticles (Au NPs) encapsulated with an ultrathin Cr-MIL-101 shell (Au@Cr-MIL-101 NPs) have been synthesized, and the thickness of Cr-MIL-101 shell can be precisely controlled to 3 nm. As a superior solid phase extraction (SPE) adsorbent, Cr-MIL-101 acts as a shell layer to effectively enrich antibiotics within the localized surface plasmon resonance (LSPR) field of Au NPs, which enhances the SERS signal and eliminates background interference. The method can achieve highly sensitive and high-throughput detection for tetracycline hydrochloride, sulfapyridine and benzylpenicillin sodium in dairy products, and the detection limits (LOD) are as low as 2.237, 2.644 and 4.662 ppb respectively. The recoveries of antibiotic residues in spiked dairy products ranged from 72.31 % to 146.7 % with matrix effects (ME) of −15.13 % to 28.68 %. Thus, this method holds significant promise for rapid detection of antibiotics in milk.
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