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Synthesis of Bimetallic Gold-Silver (Au-Ag) Nanoparticles for the Catalytic Reduction of 4-Nitrophenol to 4-Aminophenol. Catalysts 2018. [DOI: 10.3390/catal8100412] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Bimetallic gold-silver nanoparticles as unique catalysts were prepared using seed colloidal techniques. The catalytic capabilities of the nanoparticles were ascertained in the reduction of 4-nitrophenol to 4-aminophenol in the presence of sodium borohydride. Our results clearly showed that the rate of 4-NP reduction to 4-AP increased with a corresponding decrease in the diameter of the bimetallic NPs. The Au-Ag nanoparticles prepared with 5.0 mL Au seed volume indicated higher reduction activity, which was approximately 1.2 times higher than that of 2.0 mL Au seed volume in the reductive conversion of 4-NP to 4-AP. However, the monometallic NPs showed relatively less catalytic activity in the reductive conversion of 4-NP to 4-AP compared to bimetallic Au-Ag nanoparticles. Our studies also reinforced the improved catalytic properties of the bimetallic Au-Ag nanoparticles structure with a direct impact of the size or diameter and relative composition of the bimetallic catalytic nanoparticles.
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Xu L, Shen X, Li B, Zhu C, Zhou X. G-quadruplex based Exo III-assisted signal amplification aptasensor for the colorimetric detection of adenosine. Anal Chim Acta 2017. [PMID: 28622804 DOI: 10.1016/j.aca.2017.05.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Adenosine is an endogenous nucleotide pivotally involved in nucleic acid and energy metabolism. Its excessive existence may indicate tumorigenesis, typically lung cancer. Encouraged by its significance as the clinical biomarker, sensitive assay methods towards adenosine have been popularized, with high cost and tedious procedures as the inevitable defects. Herein, we report a label-free aptamer-based exonuclease III (Exo III) amplification colorimetric aptasensor for the highly sensitive and cost-effective detection of adenosine. The strategy employed two unlabeled hairpin DNA oligonucleotides (HP1 and HP2), where HP1 contained the aptamer towards adenosine and HP2 embedded the guanine-rich sequence (GRS). In the presence of adenosine, hairpin HP1 could form specific binding with adenosine and trigger the unfolding of HP1's hairpin structure. The resulting adenosine-HP1 complex could hybridize with HP2, generating the Exo III recognition site. After Exo III-assisted degradation, the GRS was released from HP2, and the adenosine-HP1 was released back to the solution to combine another HP2, inducing the cycling amplification. After multiple circulations, the released ample GRSs were induced to form G-quadruplex, further catalyzing the oxidation of TMB, yielding a color change which was finally mirrored in the absorbance change. On the contrary, the absence of adenosine failed to unfold HP1, remaining color unchanged eventually. Thanks to the amplification strategy, the limit of detection was lowered to 17 nM with a broad linear range from 50 nM to 6 μM. The proposed method was successfully applied to the detection of adenosine in biological samples and satisfying recoveries were acquired.
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Affiliation(s)
- Lei Xu
- School of Pharmacy, Nanjing Medical University, Nanjing 211166, PR China
| | - Xin Shen
- School of Pharmacy, Nanjing Medical University, Nanjing 211166, PR China
| | - Bingzhi Li
- School of Pharmacy, Nanjing Medical University, Nanjing 211166, PR China
| | - Chunhong Zhu
- School of Pharmacy, Nanjing Medical University, Nanjing 211166, PR China
| | - Xuemin Zhou
- School of Pharmacy, Nanjing Medical University, Nanjing 211166, PR China.
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Wang C, Rong Z, Wang J, Jiang N, Pang Y, Xiao R, Wang S. Seed-mediated synthesis of high-performance silver-coated magnetic nanoparticles and their use as effective SERS substrates. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2016.05.103] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Wang C, Xu Y, Deng C, Liu Z, Wang R, Zhao H. Design and preparation of a recyclable microfluidic SERS chip with integrated Au@Ag/TiO2 NTs. RSC Adv 2016. [DOI: 10.1039/c6ra14947b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Design and preparation of a recyclable microfluidic SERS chip with integrated Au@Ag/TiO2 NTs.
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Affiliation(s)
- Chunyan Wang
- Microsystem Research Center
- School of Optoelectronic Engineering
- Chongqing University
- Chongqing 400044
- China
| | - Yi Xu
- Microsystem Research Center
- School of Optoelectronic Engineering
- Chongqing University
- Chongqing 400044
- China
| | - Conghui Deng
- Bioengineering College
- Chongqing University
- Chongqing 400044
- China
| | - Zhixu Liu
- International R & D Center of Micro-nano Systems and New Materials Technology
- Chongqing University
- Chongqing 400044
- China
- Defense Key Disciplines Laboratory of Novel Micro-nano Devices and System Technology
| | - Rong Wang
- International R & D Center of Micro-nano Systems and New Materials Technology
- Chongqing University
- Chongqing 400044
- China
- Defense Key Disciplines Laboratory of Novel Micro-nano Devices and System Technology
| | - Huazhou Zhao
- International R & D Center of Micro-nano Systems and New Materials Technology
- Chongqing University
- Chongqing 400044
- China
- Defense Key Disciplines Laboratory of Novel Micro-nano Devices and System Technology
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Huang H, Shi S, Gao X, Gao R, Zhu Y, Wu X, Zang R, Yao T. A universal label-free fluorescent aptasensor based on Ru complex and quantum dots for adenosine, dopamine and 17β-estradiol detection. Biosens Bioelectron 2015; 79:198-204. [PMID: 26708240 DOI: 10.1016/j.bios.2015.12.024] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 12/10/2015] [Accepted: 12/12/2015] [Indexed: 12/16/2022]
Abstract
Based on specific aptamer binding properties, a strategy for adenosine, dopamine and 17β-estradiol detection was realised by employing Ru complex and quantum dots (QDs) as fluorescence probes. Ru complex, which could quench the fluorescence of QDs, preferred to bind with aptamer DNA and resulted in the fluorescence rise of QDs. When the aptamer DNA was incubated with the target first, it could not bind with Ru complex and the fluorescence of QDs was quenched. Under the optimal condition, the fluorescence intensity was linearly proportional to the concentration of adenosine, dopamine and 17β-estradiol with a limit of detection (LOD) of 101 nM, 19 nM and 37 nM, respectively. The experiments in fetal bovine serum were also carried out with good results. This universal method was rapid, label-free, low-cost, easy-operating and highly repeatable for the detection of adenosine, dopamine and 17β-estradiol. Qualitative detection by naked eyes was also available without complex instruments. It could also be extended to detect various analytes, such as metal ions, proteins and small molecules by using appropriate aptamers.
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Affiliation(s)
- Hailiang Huang
- Department of Chemistry, and Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092, China
| | - Shuo Shi
- Department of Chemistry, and Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092, China.
| | - Xing Gao
- Department of Chemistry, and Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092, China
| | - Ruru Gao
- Department of Chemistry, and Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092, China
| | - Ying Zhu
- Department of Chemistry, and Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092, China
| | - Xuewen Wu
- Department of Chemistry, and Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092, China
| | - Ruimin Zang
- Department of Chemistry, and Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092, China
| | - Tianming Yao
- Department of Chemistry, and Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092, China.
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Wang C, Li P, Wang J, Rong Z, Pang Y, Xu J, Dong P, Xiao R, Wang S. Polyethylenimine-interlayered core-shell-satellite 3D magnetic microspheres as versatile SERS substrates. NANOSCALE 2015; 7:18694-707. [PMID: 26502285 DOI: 10.1039/c5nr04977f] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Precise fabrication of subtle nanogaps amid individual nanoparticles or between adjacent ones to obtain the highest SERS enhancement is still a challenge. Here, we reported a novel approach for fabricating core-shell-satellite 3D magnetic microspheres (CSSM), that easily form a porous 1.5 nm PEI interlayer to accommodate molecules and create sufficient hotspots between the inner Fe3O4@Ag core and outer assembled Au@Ag satellites. Experiments and finite-difference time-domain (FDTD) simulation demonstrated that the enhancement factor (EF) was about 2.03 × 10(8) and 6.25 × 10(6), respectively. In addition, the micro-scale magnetic core endowed the CSSM with a superior magnetic nature, which enabled easy separation and further enhanced Raman signals due to enrichment of targeted analytes and abundant interparticle hotspots created by magnetism-induced aggregation. Our results further demonstrated that the CSSM is expected to be a versatile SERS substrate, which has been verified by the detection of the adsorbed pesticide thiram and the non-adsorbed pesticide paraquat with a detection limit as low as 5 × 10(-12) M and 1 × 10(-10) M, respectively. The novel CSSM can overcome the long-standing limitations of SERS for the trace characterization of various analytes in different solutions and promises to transform SERS into a practical analytical technique.
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Affiliation(s)
- Chongwen Wang
- Beijing Institute of Radiation Medicine, Beijing 100850, PR China.
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Zhang Y, Yue Y, Peng Y, Huang C, Li L, Guo L, Yang S. One-pot synthesis affords perfectly six-fold symmetrical Au microsnowflakes for excellent electrochemical biosensing and surface-enhanced Raman scattering assays. RSC Adv 2015. [DOI: 10.1039/c4ra16309e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Herein, Au microsnowflakes with six-fold symmetrical branches were successfully synthesized.
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Affiliation(s)
- Yan Zhang
- School of Chemistry and Environment
- Beihang University
- Beijing 100191
- China
| | - Yonghai Yue
- School of Chemistry and Environment
- Beihang University
- Beijing 100191
- China
| | - Yi Peng
- School of Chemistry and Environment
- Beihang University
- Beijing 100191
- China
| | - Chengcheng Huang
- School of Chemistry and Environment
- Beihang University
- Beijing 100191
- China
| | - Lidong Li
- School of Chemistry and Environment
- Beihang University
- Beijing 100191
- China
| | - Lin Guo
- School of Chemistry and Environment
- Beihang University
- Beijing 100191
- China
| | - Shihe Yang
- School of Chemistry and Environment
- Beihang University
- Beijing 100191
- China
- Department of Chemistry
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Yang T, Guo X, Wu Y, Wang H, Fu S, Wen Y, Yang H. Facile and label-free detection of lung cancer biomarker in urine by magnetically assisted surface-enhanced Raman scattering. ACS APPLIED MATERIALS & INTERFACES 2014; 6:20985-93. [PMID: 25393238 DOI: 10.1021/am5057536] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Adenosine plays a crucial role in the regulation of physiological activity in various tissues and organs. As adenosine is a possible biomarker for cancer, the determination of its level presents a demanding task for deeply monitoring progress of diseases. Through the synthesis of Fe3O4/Au/Ag nanocomposites weaved and stabilized by phytic acid and its salt, we develop a magnetically assisted surface-enhanced Raman scattering (SERS) protocol to determine trace level adenosine in urine samples from both lung cancer patients and health human. The magnetic properties of the nanocomposites enable to realize the simple separation of targeted molecules from a complex matrix and the Au/Ag nanoparticles moieties act as the SERS platform. This label-free Fe3O4/Au/Ag-nanocomposites-based SERS protocol shows a good stability, reproducibility, time efficiency (less than 20 min for one sample test), and huge sensitivity down to 1 × 10(-10) M. The protocol also has high selectivity because SERS signal of adenosine provides the molecular fingerprint information as well as an azo coupling pretreatment is performed to remove the interference of urea. Furthermore, a SERS array is designed for on-site screening adenosine in urine samples in a massive way using a portable Raman. Such a magnetically assisted SERS method as a powerful alternative can be expected as a smart and promising tool for effective assessment of healthcare.
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Affiliation(s)
- Tianxi Yang
- The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Municipal Education Committee Key Laboratory of Molecular Imaging Probes and Sensors and Department of Chemistry, Shanghai Normal University , Shanghai 200234, P. R. China
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