ANALYTICAL CHEMISTRY
·
2020
·
IF 6.785
Yang Si,Ai-Yong Zhang,Chang Liu,Dan-Ni Pei,Han-Qing Yu
Photochemical oxidation is able to effectively regenerate the fouled electrode in electrochemical pollutant monitoring, while its regeneration capacity is limited by the surface-bound hydroxyl radical speciation with low activity and mobility, which is attributed to the dissociated water adsorption on hydrophilic metal oxides. In this work, fluorine-terminated {001}-exposed TiO2 single crystals (F–TiO2) are rationally designed to construct an Au-based electrochemical sensor (Au/F–TiO2) for dopamine (DA) detection in different matrices. The Au/F–TiO2 sensor exhibits an efficient and stable detection capacity in both environmental and biological samples. A superior photochemical regeneration capacity is obtained on the Au/F–TiO2 electrode with much reduced matrix effects under UV irradiation. Spectral observation, crystallographic analysis, pollutant degradation performance, radical inhibition, and surface enhanced Raman scattering tests reveal that both the fluorine-terminated surface chemical features and the bulk-free radical speciation are mainly responsible for the superior photochemical regeneration capacity of the Au/F–TiO2 electrode. Even for the real biological samples, a stable electrochemical DA detection is also achieved on the Au/F–TiO2 sensor. Our work establishes a new approach to refine electrochemical sensors for stable monitoring and provides a robust photoactive electrode substrate with high efficiency and low cost for practical applications.
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高影响因子
MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 7
·1-10
·
IF 6.232
Liang Chunfeng,Lan Yuwei,Sun Zihua,Zhou Liya,Li Yanzhou,Liang Xinyuan,Qin Xingzhen
Carbon quantum dots co-doped with iron and nitrogen (Fe@NCDs) were synthesized by using Passiflora edulis Sims ( P. edulis ) as a precursor. The Fe@NCDs exhibit outstanding peroxidase-mimetic activity owing to successful doping with iron resulting in a behavior similar to that of iron porphyrins. In the presence of H 2 O 2 , the Fe@NCDs catalyze the oxidation of the peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) with a color change from colorless to blue. The blue oxidation product has a characteristic absorption peaking at 652 nm. A colorimetric assay was worked out for uric acid (UA) that measures the hydrogen peroxide produced during oxidation of UA by uricase. Response is linear in the 2–150 μM UA concentration range, and the limit of detection is 0.64 μM. The method was applied to the determination of UA in (spiked) urine, and recoveries ranged from 92.0 to 103.4%.
Schematic representation of the fabrication of iron and nitrogen co-doped carbon dots (Fe@NCDs) using Passiflora edulis Sims as carbon-based materials. First, uric acid (UA) was oxidized to generate H 2 O 2 by uricase. Then, the Fe@NCDs catalyzed the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to form blue-colored oxidized TMB (oxTMB) in the presence of H 2 O 2 . UA can be quantified based on the theory.
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高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2020
·Vol. 167
·期 6
·067517
·
IF 3.721
Lijun Zhang,Qianwen Li,Zhongbo Li,Zhaofang Du,Xia Hong,Longzhen Qiu
The chiral recognition of α-amino acids has attracted considerable interest because different enantiomeric amino acids show differences in their biological behavior and pharmacological activity. An organic electrochemical transistor (OECT)-based biosensor modified with L-amino acid oxidases (L-AAODX) was fabricated and successfully used as a biosensor for enantioselectively discriminating α-amino acids, such as D/L-tryptophan (D/L-Trp), D/L-tyrosine (D/L-Tyr) and D/L-phenylalanine (L-Phe) with high performance because L-AAODX selectively catalyzed the oxidation of L-Trp, L-Tyr, and L-Phe along with the amplification of OECT. The biosensor showed a sensitivity of 19.67 μA/μM with a LOD of 10 nM (S/N > 3) over the range of 10 nM to 30 μM for L-Trp, 16.71 μA/μM with a LOD of 2 nM (S/N >3) over the range of 2 nM to 30 μM for L-Tyr and 15.51 μA/μM with a LOD of 10 nM (S/N > 3) over the range of 30 nM to 30 μM for L-Phe. Furthermore, the biosensor can both be used for the chiral recognition of Trp, Tyr and Phe, and distinguish L-amino acids from its interferences (e.g., Glu, UA, L-Asp, L-Lys and L-Glu) and common metal ions (K+, Na+ and Fe3+).
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高影响因子
CHINESE JOURNAL OF ANALYTICAL CHEMISTRY
·
2020
·
IF 0.936
Lan WU,Zhi-Wei LU,Ying MA,Jun-Jun ZHANG,Guang-Quan MO,Hai-Jun DU,Jian-Shan YE
A novel electrochemical non-enzymatic sensing system was fabricated based on carbon paste electrode (CPE) encapsulating copper metal-organic frameworks (Cu-MOF/CPE) for determination of glucose by chronoamperometry in alkaline media. The as-synthesized Cu-MOF exhibited high surface area and porous structures, and the presence of carbon pastes greatly improved the conductivity of the sensing electrode. This synergic effect led to the good catalytic activity of the resulting electrode toward glucose. Under the optimized experimental conditions, the oxidation peak currents were linearly dependent on glucose concentrations in a wide range of 5–3910 μmol/L and 3910–10950 μmol/L with a limit of detection (LOD) of 0.11 μmol/L and a short response time of 0.5 s. Moreover, the developed sensor showed long-time stability, excellent selectivity as well as high resistance towards interferences. This sensor was also applied to determination of glucose in serum samples with a satisfactory result, confirming its promising applications.
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高影响因子
SENSORS
·
2020
·Vol. 20
·期 5
·1422
·
IF 3.275
Jingjing Liu,Ning Xu,Hong Men,Shuang Li,Yanli Lu,Sze Shin Low,Xin Li,Lihang Zhu,Chen Cheng,Gang Xu,Qingjun Liu
Cortisol is commonly used as a significant biomarker of psychological or physical stress. With the accelerated pace of life, non-invasive cortisol detection at the point of care (POC) is in high demand for personal health monitoring. In this paper, an ultrasensitive immunosensor using gold nanoparticles/molybdenum disulfide/gold nanoparticles (AuNPs/MoS2/AuNPs) as transducer was explored for non-invasive salivary cortisol monitoring at POC with the miniaturized differential pulse voltammetry (DPV) system based on a smartphone. Covalent binding of cortisol antibody (CORT-Ab) onto the AuNPs/MoS2/AuNPs transducer was achieved through the self-assembled monolayer of specially designed polyethylene glycol (PEG, SH-PEG-COOH). Non-specific binding was avoided by passivating the surface with ethanolamine. The miniaturized portable DPV system was utilized for human salivary cortisol detection. A series current response of different cortisol concentrations decreased and exhibited a linear range of 0.5–200 nM, the detection limit of 0.11 nM, and high sensitivity of 30 μA M−1with a regression coefficient of 0.9947. Cortisol was also distinguished successfully from the other substances in saliva. The recovery ratio of spiked human salivary cortisol and the variation of salivary cortisol level during one day indicated the practicability of the immunosensor based on the portable system. The results demonstrated the excellent performance of the smartphone-based immunosensor system and its great potential application for non-invasive human salivary cortisol detection at POC.Keywords:salivary cortisol;immunosensor;molybdenum disulfide;gold nanoparticles;differential pulse voltammetry;smartphone
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高影响因子
RSC Advances
·
2020
·Vol. 10
·期 12
·7241-7250
·
IF 3.119
Tingting Tu,Bo Liang,Qingpeng Cao,Lu Fang,Qin Zhu,Yu Cai,Xuesong Ye
With the growing number of patients suffering from noninfectious chronic diseases, the consumption of point of care testing strips increases exponentially, particularly blood glucose testing strips, causing an increasingly severe conflict between strip recycling and the environment. In this paper, fully transient electrochemical strips are developed as a substitute for non-degradable strips. Proper explorations were made, including finding out suitable degradable substrates for strip-making among different degradable materials and optimization of degradable conducting paste. Taking advantage of dissolvable polymer-based materials and nontoxic carbon materials, the transient strips have validated electrochemical functionality to determine physiological levels of glucose with a sensitivity of 14.33 μA mM−1 cm−2 (correlation coefficient R2 is 0.99498) and reached full-degradation within a week after disposal. The interference experiment (negligible interference current response under 7%) and recovery tests (recovery ratio ranging from 92.46% to 102.47%) have illustrated its practical application in real sample detection. Such degradable-characterized testing strips can be widely used in chronic disease management with daily eco-friendly point of care testing, without potential pollution to the environment.
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高影响因子
BIOSENSORS & BIOELECTRONICS
·
2020
·
IF 10.257
Zhen Liang,Jieyu Zhang,Can Wu,Xuefeng Hu,Yuhui Lu,Guangfeng Wang,Fei Yu,Xiaojun Zhang,Yunbing Wang
The commercial sensor of a continuous glucose monitoring system suffers from restricted penetration of glucose in the dense sensing coating, uncontrolled leakage of the glucose oxidase and electrocatalytic medium, and susceptibility to mechanical damage. Herein, a self-healing hydrogel based on quaternized chitosan and oxidized dextran was designed, and CeO 2 /MnO 2 hollow nanospheres were covalently linked in the hydrogel as the electrocatalytic medium. Glucose oxidase was loaded via the strong electrostatic interactions with the CeO 2 /MnO 2 hollow nanospheres. An extra covering agent was coated on the hydrogel to prevent the leakage of the glucose oxidase and electrocatalytic medium. Covalent linkage of the hydrogel on a bendable chip formed a flexible glucose sensor , which showed a wide linear range (1–111 mM), fast response (less than 3 s), and high sensitivity (176 μA mM −1 cm −2 ). The hydrogel-based sensor was self-healable, and could continuously work for over 30 days. Thus, this study provides a method to simultaneously prevent the leakage of the electrocatalytic medium, promote the sensitivity of glucose detection, and tolerate the mechanical damage, which shows great potential for continuous glucose monitoring.
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 12
·4916-4926
·
IF 3.288
Chaoli Tan,Jie Zhao,Peng Sun,Wei Zheng,Guofeng Cui
Simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA) is always of vital importance for clinical diagnosis and healthcare. Hereby, a gold nanoparticle decorated polypyrrole/graphene oxide composite on carbon fiber paper (AuNPs@GO/PPy/CFP) was facilely prepared via a two-step method. Instead of reducing GO to rGO for better conductivity, GO was combined with PPy retaining its abundant oxygen containing functional groups, which is in favor of electrochemical sensing. The as-prepared electrode was evaluated in the simultaneous determination of AA, DA and UA. During the electro-oxidation of these analytes, three well-defined peaks with low overpotentials at −0.02 V, +0.16 V and +0.28 V were observed on the modified electrode. The linear response ranges obtained were 10–1600 μM, 0.2–60 μM and 2–360 μM with the corresponding detection limits of 2.43 μM, 0.115 μM and 1.68 μM (signal/noise = 3), respectively, for AA, DA and UA. This indicates that the as-prepared electrode has an excellent catalytic capability and high selectivity for the simultaneous determination of AA, DA and UA. In addition, the modified electrode showed satisfactory results when applied in real samples, suggesting the promising potential of AuNPs@GO/PPy/CFP for practical application in complex biological systems.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2020
·Vol. 412
·期 11
·2433-2441
·
IF 3.637
Cheng Jinyan,Wang Xuedong,Nie Tianyin,Yin Long,Wang Shiman,Zhao Yanchu,Wu Huimin,Mei He
Dopamine homeostasis is an important clinical diagnostic index, because an abnormal level in the human body is closely related to certain serious diseases. Herein, a novel electrochemical sensing platform based on gold nanobipyramid/multi-walled carbon nanotube hybrids (AuNBP/MWCNTs) is developed to detect dopamine in human fluids. Using field emission scanning electron microscopy, it is observed that AuNBPs of about 60 nm with two pyramids are well dispersed on the surface of MWCNTs. Energy-dispersive X-ray spectrometry, X-ray diffraction and X-ray photoelectron spectroscopy confirm that AuNBPs are self-assembled onto the surface of MWCNTs to form the hybrids. Cyclic voltammetry reveals that the AuNBP/MWCNTs exhibit good electrocatalytic activity toward dopamine oxidation owing to the synergistic effects of AuNBPs and MWCNTs. In addition, both cyclic voltammetry and differential pulse voltammetry display three well-resolved and distinct oxidation peaks on the AuNBP/MWCNT-modified glassy carbon electrode. Based on AuNBP/MWCNTs, the newly developed electrochemical sensor is used to detect dopamine in the presence of ascorbic acid and uric acid over a wide linear range from 50 nM to 2.7 mM and a low detection limit of 15 nM (at S/N = 3). The electrochemical sensor can also be applied for the quantitative analysis of dopamine in real samples.
A novel electrochemical sensing platform based on gold nanobipyramid/multi-walled carbon nanotube hybrids (AuNBP/MWCNTs) was proposed to detect dopamine in the presence of ascorbic acid and uric acid.
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高影响因子
ANALYTICAL CHEMISTRY
·
2020
·
IF 6.785
Lu Shi,Feifei Cao,Limin Zhang,Yang Tian
The development of switches responding to specific pH changes was particularly useful in wide application fields. Owing to flexible switches simulated by pH, i-motif DNAs are widely used as a pH sensor. But its character of structure transition strongly dependent on acidic pH severely hampers the application of i-motif DNA in physiological media. Herein, we report the stable i-motif structure formed at a physiological pH triggered by spatial confinement of silica nanochannels. Three classic DNA chains containing 21-mer i-motif domain base-pairs and a single-stranded multiply (T)n spacer, 5′-COOH-(T)n-CCCTAACCCTAACCCTAACCC-3′, were employed to evaluate the enhanced stability of i-motif structure. Compared to their free states in a dilute solution, the transition pH of all i-motif DNAs decorated in nanochannels remarkably shifts toward a neutral pH. Moreover, the transition midpoint can be tuned sensitively over the physiologically relevant pH range through slightly varying the length of T base spacer. Density functional theory (DFT) calculations validate that the increased proton density in a nanochannel triggers the formation of an i-motif structure under a neutral pH. Finally, this i-motif DNA based nanochannels electrode was successfully employed to monitor pH in brain microdialysates followed by cerebral ischemia. The present approach is not limited by fundamental investigation for DNA conformation but may extend toward the manipulation of i-motif based structures for artificial molecular machines and signaling systems.
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高影响因子
Journal of Materials Chemistry B
·
2020
·Vol. 8
·期 30
·6459-6468
·
IF 5.344
Xiaodan Zhang,Yuwan Lu,Qiumeng Chen,Yuming Huang
A self-templated strategy was adopted to design hollow Co3O4/MO3 (M = Mo, W) mixed-metal oxides via the Mo or W doping of ZIF-67, and subsequent pyrolysis under an atmosphere of air at a low temperature of 450 °C. The hollow Co3O4/MO3 (M = Mo, W) mixed-metal oxides displayed tunable oxidase-like and peroxidase-like activities able to efficiently catalyze the oxidation of TMB to generate a deep blue color in the absence or presence of H2O2. Relative to that of the un-doped Co3O4, the oxidase mimic activity of the Mo-doped Co3O4 increased to 1.3 to 2.1-fold, while its peroxidase mimic activity increased to 7.1 to 19.9-fold, depending on different Mo doping amounts. The oxidase mimic activity of the W-doped Co3O4 increased to 2.1 to 2.3-fold, while its peroxidase mimic activity increased to 4.8 to 5.9-fold, depending on the different W doping amounts. The Mo- and W-doped Co3O4 nanohybrid exhibited both higher O2 and H2O2 activating capability, and their H2O2 activating capacity was superior to the O2 activating capability. Furthermore, the Mo- and W-doped Co3O4 nanohybrids exhibited similar O2 activating abilities, while the Mo-doped one displayed a higher H2O2 activating capability than the W-doped one. The discrepant peroxidase-like nature of Mo- and W-doped Co3O4 nanohybrids is likely attributed to their different catalytic mechanisms. The peroxidase-like activity of Mo-doped Co3O4 is highly related to the ˙OH free radical, while that of W-doped Co3O4 is likely ascribed to the electron transfer between TMB and H2O2. The Km values of Co3O4/MoO3 for TMB and H2O2 were 0.0352 mM and 0.134 mM, which were 3.2- and 1.9-fold lower than that of pure Co3O4, respectively. A Co3O4/MoO3-based colorimetric platform was developed for the determination of H2O2 in the 0.1–200 μM range, with a limit of detection of 0.08 μM (3σ). Based on the thiocholine (TCh) inhibition of the excellent peroxidase-like activity of Co3O4/MoO3 and the TCh generation via acetylcholinesterase (AChE) catalyzed hydrolysis of acetylthiocholine chloride (ATCh), the colorimetric platform was extended to screen AChE activity and its inhibitor.
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高影响因子
ANALYST
·
2020
·Vol. 145
·期 14
·4806-4814
·
IF 3.978
Yi Xiao,Suhua Chen,Guocan Zhang,Zhimao Li,Han Xiao,Chuanpin Chen,Chunlian He,Ran Zhang,Xiaoping Yang
Nicotine analysis is essential to medicine, toxicology and the tobacco industry. However, no simple, portable and disposable method was developed to meet their demands. Here, we report a simple, rapid and disposable silica nanochannel (SAN)-based electrochemiluminescence (ECL) sensor for nicotine analysis by simply assembling a SAN electrode with a paper cover. The sensing principle of the disposable sensor is based on the size exclusion effect and charge selectivity, which obviously prolong the sensor service time. We find that the sensor exhibits good specificity to nicotine, and most of the complex matrices are unlikely to impact the detection. The performance of the disposable sensor in cigarettes, e-cigarettes, nicotine gums, and lozenges is fully validated, showing satisfactory linearity, sensitivity (a limit of detection of 27.82 nM), and accuracy (a recovery between 96.00% and 106.51%). The disposable sensor can be potentially applied for on-site nicotine analysis.
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高影响因子
危险品化学品经营许可证（带存储）