查找使用阿拉丁产品的科研文献

Turn-on fluorescent inner filter effect-based B,S,N co-doped carbon quantum dots and vanadium oxide nanoribbons for α-glucosidase activity detection

Chenhui Yin,Meng Wu,Ting Liu,Lixing Fu,Qijun Sun,Ligang Chen,Na Niu

A sensitive and effective strategy for the screening of α-glucosidase and its inhibitors was established based on carbon quantum dots (CQDs) and vanadium oxide nanoribbons. B,S,N co-doped CQDs (BSN-CQDs) were prepared by one-step microwave hydrothermal method using o-phenylenediamine, boric acid, and thiourea as raw materials. The prepared CQDs emitted yellow fluorescence (λ em  = 565 nm) under excitation of 410 nm, and the quantum yield was 15.3%. The fluorescence of CQDs was firstly quenched by the vanadium oxide nanoribbons via inner filter effect. Then, 2-O-α-D-glucopyranosyl-L-ascorbic acid (AA2G) was introduced as a substrate of α-glucosidase to produce ascorbic acid (AA). Vanadium oxide nanoribbons could be converted to V 4+ by AA, which led to fluorescence recovery. After adding inhibitors (anti-diabetic drugs), the α-glucosidase activity was inhibited and the degree of fluorescence recovery was reduced. The established nanoprobe showed a response linearity to α-glucosidase in the range of 0.01–5 U mL −1 , with a low detection limit of 0.003 U mL −1 . This platform was applied for the screening of acarbose, with a detection limit of 0.02 μM. The constructed sensing strategy had the advantages of high selectivity, sensitivity, and was successfully used for α-glucosidase detection in serum samples and anti-diabetic drugs screening.

Polypyrrole Hollow Nanotubes Loaded with Au and Fe3O4 Nanoparticles for Simultaneous Determination of Ascorbic Acid, Dopamine, and Uric Acid

Shen Congcong,Chen Yuehua,Feng Beidou,Chi Hongying,Zhang Hua

An ultrasensitive electrochemical biosensor was fabricated for electroanalytical determination of ascorbic acid(AA), dopamine(DA) and uric acid(UA) individually and simultaneously based on polypyrrole hollow nanotubes loaded with Au and Fe 3 O 4 nanoparticles(NPs) uniformly(PPy@Au-Fe 3 O 4 ). The PPy@Au-Fe 3 O 4 nanotubes were synthesized in one-pot using MoO 3 nanorods as templates and the polymerization of Py, the formation of Au and Fe 3 O 4 NPs and the removel of MoO 3 templates took place stimultaneously. Electrochemical studies reveal that PPy@Au-Fe 3 O 4 modified glassy carbon electrode(GCE) possesses excellent electrocatalytic activities toward the oxidation of AA, DA and UA. Their oxidation peak currents increase linearly in the concentration ranges of 1–2000 µmol/L for AA, 0.01–25 and 25–300 µmol/L for DA and 0.1–300 µmol/L for UA. Their detection limit values( S/N =3) were calculated as 0.45, 0.0049, and 0.051 µmol/L for AA, DA and UA in the individual detection. By changing the concentrations simultaneously, the calibration curves showed linearity to 1000, 200, and 200 µmol/L with detection limit of 0.39, 0.0060, and 0.060 µmol/L for AA, DA, and UA, respectively. Finally, the obtained biosensor was successfully applied to the detection of AA, DA, and UA with satisfactory results on actual samples.

Sensitive and selective electrochemical determination of uric acid in urine based on ultrasmall iron oxide nanoparticles decorated urchin-like nitrogen-doped carbon

Tingfan Tang,Menglin Zhou,Jiapei Lv,Hao Cheng,Huaisheng Wang,Danfeng Qin,Guangzhi Hu,Xiaoyan Liu

Hypercrosslinked pyrrole was synthesized via the Friedel–Crafts reaction and then carbonized to obtain urchin-like nitrogen-doped carbon (UNC). Ultrasmall iron oxide nanoparticles were then supported on UNC, and the composite was used to prepare an electrochemical sensor for detecting uric acid (UA) in human urine. Fe x O y /UNC was characterized and analyzed via scanning electron microscopy, transmission electron microscopy, energy dispersive spectrometry, X-ray diffraction, and X-ray photoelectron spectroscopy. A glassy carbon electrode (GCE) modified with Fe x O y /UNC was used as an electrochemical sensor to effectively identify UA. The electrochemical behavior of the Fe x O y /UNC-based UA sensor was studied using differential pulse stripping voltammetry, and the optimal conditions were determined by changing the amount of Fe x O y /UNC, pH of the buffer solution, deposition potential, and deposition time. Under optimal conditions, the Fe x O y /UNC-based electrochemical sensor detected UA in the range of 2–200 μM, where the limit of detection (LOD) for UA was 0.29 μM. Anti-interference experiments were performed, and the sensor was applied to the actual analysis of human urine samples. Urea, glucose, ascorbic acid, and many cations and anions present at 100-fold concentrations relative to UA did not strongly interfere with the response of the sensor to UA. The Fe x O y /UNC electrochemical sensor has high sensitivity and selectivity for uric acid in human urine samples and can be used for actual clinical testing of UA in urine.

Determination of prostate-specific antigen via the assembly of a two-dimensional nanoplatform

Chen Junjie,Li Xiangqian,Yu Xiaoqi,Zhou Wei,Wang Qianming

Two-dimensional platforms generate considerable interests due to diverse application. We report a “turn-on” fluorescent nanoprobe for prostate-specific antigen (PSA) detection. It is based on cobalt oxyhydroxide nanosheets (CoOOH NSs). Fluorescein amidite (abbreviated as FAM)-labeled aptamer probe (abbreviated as FAM-aptamer) has been adsorbed onto the nanosheets. Energy transfer between substrate and optical species has induced the quenching of FAM-aptamer emission. The strong affinity of FAM-aptamer to the target PSA causes the formation of a rigid aptamer structure. The integration between FAM-aptamer and CoOOH NSs has been drastically affected. The release of the aptamer probe from the nanosheet surface has been realized. The green luminescence has been recovered. The dynamic nanosensor exhibits highly sensitive performance toward PSA with a linear detection range from 0.1 to 5 ng/mL. Its detection limit is measured to be 56.1 pg/mL. Therefore, a simple and efficient sensing platform for the detection of prostate cancer can be established.

Electrochemical determination of dopamine and uric acid with covalent organic frameworks and Ox-MWCNT co-modified glassy carbon electrode

Hao Guo,Bingqing Liu,Zhilan Pan,Lei Sun,Liping Peng,Yuan Chen,Ning Wu,Mingyue Wang,Wu Yang

s Covalent organic frameworks (COFs) have received tremendous interest due to their structural diversity and versatility. These unique physicochemical properties make them exhibit great application potential in the field of electrochemical sensor. In this study, an imine bond-linked COF with porosity and large specific surface area was fabricated by a dehydration condensation reaction between 1, 3, 5-tris(4-formylphenyl)benzene (TFPB) and 1, 3, 5-tris(4-aminophenyl) benzene (TAPB) and combined with high electrical conductivity of oxidized multi-walled carbon nanotube (Ox-MWCNT). The structure of the COF and the resulted composite material were confirmed through a series of characterization techniques, including Fourier-transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy and thermogravimetric analysis , then a co-modified glassy carbon electrode was constructed for simple, sensitive and selective electrochemical recognition of dopamine (DA) and uric acid (UA). The fabricated electrochemical sensor displayed a strong current response to both DA and UA in the phosphate buffer solution (PBS) at pH = 6.5. The synergistic effect between COFs and Ox-MWCNT effectively improved the analytical sensitivity for the target analytes. Under optimized experimental conditions, the method showed good performance for DA and UA in the concentration range of 0.6–250.0 μM with low detection limits of 0.073 μM and 0.063 μM (S/N = 3), respectively. Moreover, the proposed sensor exhibited high selectivity , longtime stability, desirable repeatability and acceptable reproducibility and can be used to analyze simultaneously DA and UA in biological and medicine samples with satisfactory results. Our work not only provides a simple way to detect DA and UA quantitatively in real samples, but also offers a new platform for COF-based composite application in electrochemical sensing .

High-sensitivity detection for cantharidin by ratiometric fluorescent sensor based on molecularly imprinted nanoparticles of quantum dots

Jiang Ling,Wenqi Zhang,Zijia Cheng,Yanjun Ding

Cantharidin (CTD), an effective component of Chinese herbal medicine with unique efficacy, caused poisoning or death constantly for incorrect use. Therefore, there is an intense need for a reliable, selective, sensitive and low-costing analytical method for monitoring the concentration of CTD in biological samples. In this work, a ratiometric fluorescent sensor (CdTe@MIPs/CDs@NIPs) was successfully constructed for selective determination of CTD by simply integrated the non-imprinted polymers coated CDs (CDs@NIPs) with cadmium telluride quantum dots coated with molecular imprinted polymers (CdTe@MIPs). CDs@NIPs were directly used as reference signal without addition of CTD templates and the as-prepared CdTe@MIPs were response signal. With the CTD addition, the fluorescence intensity of CdTe@MIPs decreased, while the fluorescence of CDs@NIPs remained approximately unchanged, resulting a detection limit as low as 0.15 nM. By spiked human blood samples, the ratiometric sensor was successfully applied to CTD detection with good recoveries of 96.12–107.40% and relative standard deviation (RSD) of 2.87–3.96%. Moreover, after centrifuging and re-eluting, the developed sensor could be effectively recycled and reused five times. Significantly, the proposed platform with low-cost and high-sensitivity opens a door towards the practical applications of ratiometric sensor and shows immense potential in pursuing the sensitive, reliable and low-cost determination of poisons in forensic toxicology analysis.

Electrochemically functionalized carbon cloth for simultaneous determination of ascorbic acid, dopamine, and uric acid

Shuang Ding,Manxia Dai,Xinglin Su,Di Guo,Lijun Bian,Xiaoxia Liu

We modified commercial carbon cloth with oxygen-containing groups and doped nitrogen by electrochemical treatment (the modified carbon cloth was named FCC). Electrodes of different O/C and N/C content ratios were fabricated through varying the potential of the electrochemical treatment. The physical morphology and chemical composition of FCC electrodes were characterized using scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The introduced functional groups greatly improved the performance of the FCC electrodes for the detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA). Individual and simultaneous detection of AA , DA, and UA were conducted on the FCC electrodes through differential pulse voltammetry. The FCC electrodes showed a linear response to AA, DA, and UA in the concentration ranges of 0.1–4 mM, 0.02–3 μM, and 0.1–10 μM, respectively, with detection limits of 5.8, 0.014, and 0.066 μM.

In Situ Growing CuO/ZIF-8 into Nickel Foam to Fabricate a Binder-Free Self-Supported Glucose Biosensor

Lei Deng,Senqing Fan,Yu Chen,Jiaojiao Chen,Zenghui Mai,Zeyi Xiao

A binder-free self-supported CuO/ZIF-8@NiF electrode is fabricated with CuO/ZIF-8 particles in situ growth in nickel foam pores. ZIF-8 is first assembled inside the nickel foam pores and then Cu2+ is adsorbed around the surface of ZIF-8 crystal, and finally reduced and oxidized to form CuO. Scanning electron microscopy indicates CuO is uniformly distributed on the surface of ZIF-8. The Cu element is significantly increased from 1.16 to 30.91 mg·g–1 under the existence of ZIF-8 from inductively coupled plasma results. The electrochemical analyses show that the electrochemical active surface area of the CuO/ZIF-8@NiF electrode can be increased two times while its electronic transport resistance can be reduced to one-seventh compared with the CuO/ZIF-8/NiF electrode with CuO/ZIF-8 binding on the substrate. The detection tests exhibit enhanced electrochemical properties with a sensitivity of 5640 μA·mM–1·cm–2, a low detection limitation of 0.1 μM, and a linear detection range from 0.5 to 120 μM. The biosensor presents good anti-interference property, stability, and a 101.08–104.53% recovery rate.

SERS determination of dopamine using metal–organic frameworks decorated with Ag/Au noble metal nanoparticle composite after azo derivatization with p-aminothiophenol

Zhu Anni,Wang Tiansheng,Jiang Yuning,Hu Sen,Tang Wanxin,Liu Xinling,Guo Xiaoyu,Ying Ye,Wu Yiping,Wen Ying,Yang Haifeng

A specific surface-enhanced Raman scattering (SERS) assay for dopamine (DA) based on an azo derivatization reaction is proposed for the first time by preparation of p-aminothiophenol (PATP)-modified composite SERS substrate, composed of metal–organic framework (MIL-101) decorated with Au and Ag nanoparticles. As the result, the SERS method for detection of the azo reaction between PATP and DA exhibits superior sensitivity, selectivity, and stability. A reasonable linearity in the range 10 −6 to 10 −10  mol∙L −1 is achieved, and the limit of detection is 1.2 × 10 −12  mol∙L −1 . The reactive SERS assay is free from interference in complex physiological fluid. The feasibility of the proposed SERS method for the detection of DA levels in fetal bovine serum (FBS) samples and human serum samples is validated by HPLC–MS methods, displaying promising application potential in early disease diagnosis. Graphical abstract

Carbon Cloth Loaded NiCo2O4 Nano-Arrays to Construct Co-MOF@GO Nanocubes: A High-Performance Electrochemical Sensor for Non-Enzymatic Glucose

Bairui Tao,Jiao Li,Fengjuan Miao,Yu Zang

Fe doping induced formation of crystalline/amorphous NiCo2O4 core/shell heterostructure for highly sensitive nonenzymatic detection of glucose

Chengcheng Qi,Chongchao Zhang,Ziyin Yang

A novel strategy was reported to improve electrocatalytic activity of NiCo 2 O 4 by doping Fe. It is interesting to find that the doping of Fe induces formation of nanorod composing with crystalline core and thin amorphous shell. The composition, structure and properties of NiCo 2 O 4 are well characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry and amperometric method. The results display that the presence of thin amorphous shell is conducive to accelerating electron transfer rate and exposing more effective active sites, therefore making the sensor based on Fe-doped NiCo 2 O 4 detect glucose in a wide linear range from 0.2 μM to 3.1 mM with a high sensitivity of 3055.7 μA mM −1 cm −2 and a low detection limit of 0.19 μM. This unique crystalline core/amorphous shell-structured NiCo 2 O 4 demonstrates promising potential as an effective electrocatalyst for glucose sensing.

A flexible electrochemical biosensor based on functionalized poly(3,4-ethylenedioxythiophene) film to detect lactate in sweat of the human body

Chonghui Zhu,Yifeng Xu,Qidai Chen,Hongran Zhao,Bingrong Gao,Tong Zhang

Conductive polymers with good flexibility, conductivity and film-forming ability attract a lot of attention. In this work, a large-area and ordered structure poly(3,4-ethylenedioxythiophene) (PEDOT) film is fabricated at the air-water interface through interface synthesis method. The PEDOT film can be directly placed on a flexible screen-printed electrode, but also has good adhesion between them. The surface of the PEDOT film is relatively smooth, and has good electrical conductivity and flexibility. Lactate oxidase is immobilized on the surface of PEDOT film through a combination of cross-linking and adsorption method to enhance the lactate sensitive performances. The results show that the PEDOT film sensor has excellent stability and reproducibility. The PEDOT film sensor shows a good response to lactate, the working range is 0.25–40 mmol L −1 , and the detection limit is 0.083 mmol L −1 (S/N = 3). Moreover, the electrochemical sensor has potential application in detecting lactate in sweat of the human body.