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1.
Adv Mater ; : e2401508, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38747492

RESUMO

Electronic stethoscope used to detect cardiac sounds that contain essential clinical information is a primary tool for diagnosis of various cardiac disorders. However, the linear electromechanical constitutive relation makes conventional piezoelectric sensors rather ineffective to detect low-intensity, low-frequency heart acoustic signal without the assistance of complex filtering and amplification circuits. Herein, it is found that triboelectric sensor features superior advantages over piezoelectric one for microquantity sensing originated from the fast saturated constitutive characteristic. As a result, the triboelectric sensor shows ultrahigh sensitivity (1215 mV Pa-1) than the piezoelectric counterpart (21 mV Pa-1) in the sound pressure range of 50-80 dB under the same testing condition. By designing a trumpet-shaped auscultatory cavity with a power function cross-section to achieve acoustic energy converging and impedance matching, triboelectric stethoscope delivers 36 dB signal-to-noise ratio for human test (2.3 times of that for piezoelectric one). Further combining with machine learning, five cardiac states can be diagnosed at 97% accuracy. In general, the triboelectric sensor is distinctly unique in basic mechanism, provides a novel design concept for sensing micromechanical quantities, and presents significant potential for application in cardiac sounds sensing and disease diagnosis.

2.
Ann Hum Biol ; 51(1): 2330926, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38634541

RESUMO

BACKGROUND: Chronic hepatitis B virus (HBV) infection is a severe disease affecting the physical and economic well-being of patients. The relationship between polymorphisms in the MTHFR gene and disease progression following HBV infection remains a controversial topic. AIM: To study MTHFR and MTRR gene polymorphisms in patients with chronic HBV infections in Zigong, Sichuan Province. SUBJECTS AND METHODS: One hundred and ninety-one patients with chronic HBV infections were divided into three groups: the chronic hepatitis B (CHB) group (n = 71), the hepatitis B-induced liver cirrhosis (LC) group (n = 56), and the hepatitis B-related primary liver cancer (PLC) group (n = 64). The gene polymorphisms were detected using the PCR-melt curve method and analysed. RESULTS: The distributions of MTHFR C677T (CC: 41.2% vs. 41.8%; CT: 50% vs. 45.5%; TT: 8.8% vs. 12.7%; p = 0.714), MTHFR A1298C (AA: 70.6% vs. 72.7%; AC: 26.5% vs. 25.5%; CC: 2.9% vs. 1.8%; p = 1.000), and MTRR A66G (AA: 58.1% vs. 65.5%; AG: 39.0% vs. 29.1%; 2.9% vs. 5.5%; p = 0.353) genetic polymorphisms did not vary between male and female patients from Zigong. In addition, there were no differences in the distributions of MTHFR C677T (CC: 43.4% vs. 38.8%; CT: 49.1% vs. 48.2%; TT: 7.5% vs. 12.9%; p = 0.444), MTHFR A1298C (AA: 76.4% vs. 64.7%; AC: 20.8% vs. 32.9%; CC: 2.8% vs. 2.4%; p = 0.155), and MTRR A66G (AA: 62.3% vs. 57.6%; AG: 34.0% vs. 38.8%; 3.8% vs. 3.5%; p = 0.353) genetic polymorphisms between the patients <60 and >60 years of age. The distributions of MTHFR C677T (CHB vs. LC, p = 0.888; CHB vs. PLC, p = 0.661; PLC vs. LC, p = 0.926), MTHFR A1298C (CHB vs. LC, p = 0.12; CHB vs. PLC, p = 0.263; PLC vs. LC, p = 0.550), and MTRR A66G (CHB vs. LC, p = 0.955; CHB vs. PLC, p = 0.645; PLC vs. LC, p = 0.355) gene polymorphisms were comparable between the CHB, LC, and PLC groups. CONCLUSION: The distributions of MTHFR and MRRR genetic polymorphisms in the population with HBV infections in Zigong, Sichuan Province did not differ in age and sex. The MTHFR and MRRR genetic polymorphisms were comparable between the CHB, LC, and PLC groups.


Assuntos
Hepatite B Crônica , Feminino , Humanos , Masculino , Estudos de Casos e Controles , China/epidemiologia , Predisposição Genética para Doença , Genótipo , Hepatite B Crônica/genética , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Polimorfismo de Nucleotídeo Único , Ferredoxina-NADP Redutase/genética
3.
Biosens Bioelectron ; 253: 116194, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38467100

RESUMO

The multiplexed detection of metabolites in parallel within a single biosensor plate is sufficiently valuable but also challenging. Herein, we combine the inherent light addressability of silicon with the high selectivity of enzymes, for the construction of multiplexed photoelectrochemical enzymatic biosensors. To conduct a stable electrochemistry and reagentless biosensing on silicon, a new strategy involving the immobilization of both redox mediators and enzymes using an amide bond-based hydrogel membrane was proposed. The membrane characterization results demonstrated a covalent coupling of ferrocene mediator to hydrogel, in which the mediator acted as not only a signal generator but also a renewable sacrifice agent. By adding corresponding enzymes on different spots of hydrogel membrane modified silicon and recording local photocurrents with a moveable light pointer, this biosensor setup was used successfully to detect multiple metabolites, such as lactate, glucose, and sarcosine, with good analytical performances. The limits of detection of glucose, sarcosine and lactate were found to be 179 µM, 16 µM, and 780 µM with the linear ranges of 0.5-2.5 mM, 0.3-1.5 mM, and 1.0-3.0 mM, respectively. We believe this proof-of-concept study provides a simple and rapid one-step immobilization approach for the fabrication of reagentless enzymatic assays with silicon-based light-addressable electrochemistry.


Assuntos
Técnicas Biossensoriais , Silício , Eletroquímica/métodos , Sarcosina , Técnicas Biossensoriais/métodos , Hidrogéis , Lactatos , Glucose
4.
J Inflamm Res ; 17: 279-299, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38229689

RESUMO

Background: Sepsis was a high mortality and great harm systemic inflammatory response syndrome caused by infection. lncRNAs were potential prognostic marker and therapeutic target. Therefore, we expect to screen and analyze lncRNAs with potential prognostic markers in sepsis. Methods: Transcriptome sequencing and limma was used to screen dysregulated RNAs. Key RNAs were screened by correlation analysis, lncRNA-mRNA co-expression and weighted gene co-expression network analysis. Immune infiltration, gene set enrichment analysis and gene set variation analysis were used to analyze the immune correlation. Kaplan-Meier curve, receiver operator characteristic curve, Cox regression analysis and nomogram were used to analyze the correlation between key RNAs and prognosis. Sepsis model was established by lipopolysaccharide-induced HUVECs injury, and then cell viability and migration ability were detected by cell counting kit-8 and wound healing assay. The levels of apoptosis-related proteins and inflammatory cytokines were detected by RT-qPCR and Western blot. Reactive Oxygen Species and superoxide dismutase were detected by commercial kit. Results: Fourteen key differentially expressed lncRNAs and 663 key differentially expressed genes were obtained. And these lncRNAs were closely related to immune cells, especially T cell activation, immune response and inflammation. Subsequently, Subsequently, lncRNA PRKCQ-AS1 was identified as the regulator for further investigation in sepsis. RT-qPCR results showed that PRKCQ-AS1 expression was up-regulated in clinical samples and sepsis model cells, which was an independent prognostic factor in sepsis patients. Immune correlation analysis showed that PRKCQ-AS1 was involved in the immune response and inflammatory process of sepsis. Cell function tests confirmed that PRKCQ-AS1 could inhibit sepsis model cells viability and promote cell apoptosis, inflammatory damage and oxidative stress. Conclusion: We constructed immune-related lncRNA-mRNA regulatory networks in the progression of sepsis and confirmed that PRKCQ-AS1 is an important prognostic factor affecting the progression of sepsis and is involved in immune response.

5.
Shock ; 60(6): 753-761, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-37878499

RESUMO

ABSTRACT: Background : We explored the efficacy and main biological mechanism of geniposide intervention in sepsis. Methods : A sepsis model was established in male BALB/c mice through cecal ligation and puncture (CLP). Different doses of geniposide (20 or 40 mg/kg) were administered intravenously at 0 and/or 24 h after CLP surgery. The survival rate of different groups was observed. In addition, the expression levels of CD16 and major histocompatibility complex class II in monocytes were assessed using flow cytometry. The concentrations of TNF-α, IL-1ß, IL-6, and IL-10 in the serum were measured by ELISA. We also observed the biological effects of geniposide on CD16 and MHC-II expression levels in RAW264.7 cells, as well as the secretion of TNF-α, IL-1ß, IL-6, and IL-10 in the LPS-induced RAW264.7 cell model. The PPARγ levels were determined using western blot analysis. Results : Intravenous administration of 40 mg/kg of geniposide at 0 h after CLP significantly improved the survival outcomes in the septic mouse model, with no significant benefits from low dosing (20 mg/kg) or delayed administration (24 h). The effective dose of geniposide significantly decreased the serum cytokine TNF-α, IL-1ß, IL-6, and IL-10 concentrations in septic mice ( P < 0.05). Notably, in vitro assays showed that geniposide specifically increased the IL-10 level. Geniposide significantly reduced the CD16 expression ( P < 0.05) and increased MHC-II expression in monocytes ( P < 0.05). In addition, geniposide elevated the PPARγ level in monocytes ( P < 0.05). Conclusions : High-dose early-stage geniposide administration significantly improved the survival rate in a CLP mouse sepsis model by modulating the monocyte phenotype and regulating the cytokine network (IL-6/IL-10 levels). The pharmacological mechanism of geniposide action might be exerted primarily through PPARγ upregulation.


Assuntos
Citocinas , Sepse , Camundongos , Masculino , Animais , Citocinas/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Interleucina-10/metabolismo , Monócitos/metabolismo , PPAR gama/metabolismo , Interleucina-6/metabolismo , Prognóstico , Punções , Sepse/metabolismo , Fenótipo
6.
Medicine (Baltimore) ; 102(43): e35699, 2023 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-37904480

RESUMO

BACKGROUND: Hepatitis B virus (HBV) is closely related to the occurrence and development of primary liver cancer (PLC). The early diagnosis of PLC is difficult. The study explored the clinical application value of the HBV gene basal core promoter (BCP) region 1762/1764 combined with gamma-glutamyl transpeptidase (GGT) and its isozyme II (GGTII) in PLC. METHODS: From June 2017 to June 2021, 145 hepatitis B surface antigen-positive and HBV DNA-positive patients were enrolled in the Third People Hospital of Zigong. Of them, 67 were chronic hepatitis B (CHB) patients, 30 were liver cirrhosis patients, and 48 were patients with hepatitis B-associated PLC. The HBV BCP 1762/1764 mutation was detected through the amplification refractory mutation system fluorescence PCR method, and GGTII was detected using the double-antibody sandwich method. RESULTS: The results showed that the serum GGT activity, GGTII level, aspartate aminotransferase (AST) activity, AST/alanine aminotransferase (ALT) ratio, GGT/ALT ratio, and GGT/AST ratio were significantly different between the PLC and CHB groups. Statistically significant differences in serum GGT activity, AST activity, and GGT/ALT ratio were observed between the PLC and LC groups. The BCP 1762/1764 mutation rate between the PLC and CHB groups was statistically significant. The GGTII level in the early PLC (stage I + II) group and the advanced PLC (stage III + IV) group was higher than that in the N-PLC group. Serum GGT activity in the early PLC and advanced PLC groups was higher than that in the N-PLC group. The area under the curve of the receiver operator characteristic curve of GGT and GGTII for diagnosing PLC was 0.775 (95% confidence interval [CI] [0.697, 0.854]) and 0.608 (95% CI [0.512, 0.704]), respectively. The area under curve of GGT and GGTII for diagnosing early PLC was 0.732 (95% CI [0.620, 0.845]) and 0.579 (95% CI [0.452, 0.706]), respectively. CONCLUSION: HBV gene BCP 1762/1764 mutation, GGT, and GGTII may be related to PLC occurrence. The HBV gene BCP region 1762/1764 combined with GGT has certain clinical diagnostic values for PLC and early PLC. However, GGTII is not a good indicator of early PLC and is more relevant to advanced PLC.


Assuntos
Hepatite B Crônica , Neoplasias Hepáticas , Humanos , Vírus da Hepatite B/genética , DNA Viral , gama-Glutamiltransferase/genética , Neoplasias Hepáticas/genética , Alanina Transaminase
7.
Anal Chem ; 95(23): 8898-8905, 2023 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-37249570

RESUMO

Label-free electrochemical visualization of cancer cell apoptosis is essential for cancer therapies. In this work, we proposed a noninvasive imaging method using a light-addressable electrochemical sensor (LAES) for label-free imaging of drug-induced tumor cell apoptosis. The dynamic AC photocurrent changes on MCF-7 human breast adenocarcinoma cells after inducing by tamoxifen were imaged. And the reasons for photocurrent changes on the cells were explored by monitoring the changes in the ζ potentials of cells and Faradic impedance. The results demonstrated that the AC photocurrent on apoptotic MCF-7 cells increased, and the apoptosis degree of each cell was heterogeneous. Moreover, the AC photocurrent increase was attributed to the increased cell membrane permeability and the increased gap between the cell basal surface and the substrate caused by cell apoptosis. This study provides a brand new approach for label-free visualizing cell apoptosis heterogeneity, which has great potential in apoptosis-associated drug screening or drug efficacy evaluation.


Assuntos
Apoptose , Neoplasias da Mama , Humanos , Feminino , Tamoxifeno/farmacologia , Neoplasias da Mama/patologia , Células MCF-7
8.
Talanta ; 254: 124124, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36459873

RESUMO

The application of silicon (Si) substrate as photoelectrode in light-addressable electrochemistry (LAE) is severely limited due to its ease of surface oxidation. The resulted silicon oxide (SiOx) layer is electronically insulating and blocks charge transfer between the electrode and electrolyte. Keeping the Si from being oxidized is a key challenge for its practical use as a semiconductor electrode. In this work, we find that by developing a thin layer of polydopamine film on the surface of Si substrate, followed by carbonization at 550 °C, the natural oxidation of Si substrate can be successfully forestalled. When applied as an electrode, it is further found that the carbonized polydopamine (cPDA) layer can also prevent anodic oxidation of Si. The cPDA layer-modified Si substrate exhibits good photoelectrochemical performance and great stability, with no obvious signal decrease under ambient environment over 32 h. Our work here provides a new modification strategy for anti-oxidation of Si substrate and it is promising in the application of light-addressable electrochemical sensing and imaging.


Assuntos
Indóis , Dióxido de Silício , Eletrodos , Oxirredução
9.
Anal Chim Acta ; 1224: 340237, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35998993

RESUMO

Visualization of the electrochemical reaction is essential for comprehensively understanding the electrochemical reaction mechanism and precisely characterizing dynamic electrochemical processes. Herein, we propose a simple device that combines light-addressable potentiometric sensor (LAPS) imaging and microelectrodes to serve as a general electroanalysis platform for the label-free sensing and imaging of electrochemical reactions. In this device, two microelectrodes are assembled on the LAPS chip. Electrochemical reactions occurring on the microelectrodes can be qualitatively and quantitatively observed and visualized using a LAPS chip that is sensitive to the reaction products. Validations were performed to monitor the effect of water electrolysis and potassium ferrocyanide oxidation surrounding the microelectrodes, respectively. We believe that this study will provide an excellent platform for the visualization and monitoring of electrochemical reactions and broaden the application scope of LAPS imaging to a general electroanalysis tool that is widely applicable in several fields.


Assuntos
Técnicas Biossensoriais , Técnicas Biossensoriais/métodos , Microeletrodos , Oxirredução , Potenciometria
10.
Front Cardiovasc Med ; 9: 904250, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35795375

RESUMO

Background and Purpose: Multiple guidelines suggest the ω-3 polyunsaturated fatty acids (ω-3 PUFAs) help to prevent major vascular events of coronary heart disease (CHD), but the data on large trials of ω-3 fatty acids are controversial. We reviewed the available evidence to determine the effect of ω-3 PUFAs on coronary atherosclerosis. Materials and Methods: Literature were from online databases. Randomized controlled trials (RCTs) or observational studies were acceptable. Quantitative data synthesis was conducted using R version 4.1.2. Each outcome was calculated using standardized mean difference (SMD) in a random-effect model. Sensitivity analysis was conducted for each outcome. A total of 21 RCTs and 1 observational study with 2,277 participants were included. Results: Meta-analysis indicated a benefit of ω-3 PUFAs on coronary atherosclerosis, namely, (1) ω-3 PUFAs can reduce the atherosclerotic plaque volume (SMD -0.18; 95% CI -0.31 to -0.05); (2) ω-3 PUFAs can help reduce the loss of the diameter of the narrowest segments of coronary arteries in patients with CHD (SMD 0.29; 95% CI, 0.05-0.53); (3) ω-3 PUFAs do not have significant effect on volume of lipid plaque in coronary arteries (SMD -1.18; 95% CI -2.95 to 0.58), volume of fiber plaque (SMD 0.26; 95% CI -0.81 to 1.33), and calcified plaque (SMD 0.17; 95% CI -0.55 to 0.89); and (4) ω-3 PUFAs had no significant effect on endothelial inflammatory factors in peripheral blood. Conclusions: We confirmed that ω-3 PUFAs benefit patients with CHD by reducing the progression of coronary atherosclerosis. We indicated that the benefits were not caused by reducing endothelial inflammations of coronary arteries. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021285139, identifier: CRD42021285139.

11.
ACS Sens ; 7(7): 1791-1807, 2022 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-35762514

RESUMO

The light-addressable electrochemical sensor (LAES) is a recently emerged bioanalysis technique combining electrochemistry with the photoelectric effect in a semiconductor. In an LAES, a semiconductor substrate is illuminated locally to generate charge carriers in a well-defined area, thereby confining the electrochemical process to a target site. Benefiting from the unique light addressability, an LAES can not only detect multiple analytes in parallel within a single sensor plate but also act as a bio(chemical) imaging sensor to visualize the two-dimensional distribution of specific analytes. An LAES usually has three working modes: a potentiometric mode using light-addressable potentiometric sensors (LAPS) and an impedance mode using scanning photoinduced impedance microscopy (SPIM), while an amperometric mode refers to light-addressable electrochemistry (LAE) and photoelectrochemical (PEC) sensing. In this review, we describe the detection principles of each mode of LAESs and the concept of light addressability. In addition, we highlight the recent progress and advance of LAESs in spatial resolution, sensor system design, multiplexed detection, and bio(chemical) imaging applications. An outlook on current research challenges and future prospects is also presented.


Assuntos
Técnicas Biossensoriais , Técnicas Biossensoriais/métodos , Eletroquímica , Potenciometria , Semicondutores
12.
Front Chem ; 9: 753253, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34805092

RESUMO

A novel homogeneous label-free electrochemical biosensor using G-triplex/methylene blue (G3/MB) complex as the signal generator together with an amplification assisted by the λ-exonuclease (λ-Exo) has been successfully constructed for ultrasensitive microRNA (miRNA) detection. An integrated microelectrode was designed to realize the miniaturization of the homogeneous electrochemical assay. Taking advantage of G3, that can specifically bind with MB and decrease its diffusion current, a single-stranded functional DNA hairpin structure was designed as the bio-recognition probe. The probe consisted of G3, eight bases to block G3, and the complementary sequences of the target miRNA. Here we chose miRNA141-a potentially diagnostic biomarker of prostate cancer as the model target. The presence of miRNA141 could hybridize with the probe DNA to form a double-stranded structure with a 5'-phosphorylated terminus. Then λ-Exo was adopted to digest mononucleotides from the 5'-end, leading to the release of G3 part and miRNA141. The released miRNA could hybridize with another probe to trigger the cycling process, while the released G3 could therefore interact with MB to cause a detectable decrease of diffusion current. The proposed strategy showed a low detection limit of 16 fM and an excellent specificity to discriminate single-base mismatches. Furthermore, this sensor was applied to detect miRNA141 from diluted human serum samples, indicating that it has great potential in the application of nucleic acid detection in real samples.

13.
Anal Chim Acta ; 1158: 338415, 2021 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-33863408

RESUMO

A miniaturized platform combining integrated microelectrode (IME) and functional nucleic acids was developed for homogeneous label-free electrochemical biosensing. IME was constructed with a carbon fiber microelectrode and a platinum wire in a θ type glass tube as a two-electrode system for electrochemical monitoring at microliter level. A newly reported G-triplex/methylene blue (G3/MB) complex was used as the signal generator in the homogeneous label-free electrochemical biosensor. G3 has strong affinity with MB and it can cause significant decrease of the diffusion current of MB after binding. Melamine was chosen as the model target. Since melamine can interact with nucleobase thymine (T) to form T-melamine-T structure through complementary hydrogen bonds, a single-strand functional DNA hairpin structure with poly T and G3 elaborately blocked via base pairing was designed. The presence of melamine can trigger the conformation switching of the DNA hairpin to release the G3. The released G3 combined with MB could therefore change the diffusion current, leading to a simple and rapid detection of melamine. The combination of functional DNA hairpin as target recognition element, G3/MB as signal generator, and IME as transducer provided a "Mix and Measure" miniaturized platform for the construction of homogeneous label-free electrochemical biosensors.


Assuntos
Técnicas Biossensoriais , Ácidos Nucleicos , DNA , Técnicas Eletroquímicas , Microeletrodos
14.
ACS Sens ; 6(4): 1636-1642, 2021 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-33832225

RESUMO

Here, we describe a new photoelectrochemical imaging method termed light-addressable square wave voltammetry (LASWV). It measures local SWV currents at an unstructured electrolyte/insulator/semiconductor (EIS) field-effect substrate by illuminating and addressing the substrate with an intensity-constant laser. Due to the continuous generation of charge carriers in the light-irradiated semiconductor, the drift and diffusion of photoinjected carriers within the semiconductor bulk would slow down the equilibrium processes of charge and discharge in one potential pulse cycle. Therefore, even though SWV is sampled at the end of the direct and reverse pulses to reject capacitive currents, in our approach, photoinduced capacitive current can still be detected as an effective sensory signal. The obtained current-potential (I-V) curve shows a typical shape corresponding to the accumulation, depletion, and inversion regions of field-effect devices. We demonstrated that LASWV can be used as a field-effect chemical sensor to measure the solution pH and monitor enzymatic reactions. More importantly, since the charge carriers are only generated in the illuminated area, the laser spot in the device can be used as a virtual probe to record local electrochemical properties such as impedance with microresolution.


Assuntos
Técnicas Biossensoriais , Impedância Elétrica , Eletrólitos , Luz , Semicondutores
15.
Biosens Bioelectron ; 180: 113121, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33706156

RESUMO

Photoelectrochemical imaging has great potential in the label-free investigation of cellular processes. Herein, we report a new fast photoelectrochemical imaging system (PEIS) for DC photocurrent imaging of live cells, which combines high speed with excellent lateral resolution and high photocurrent stability, which are all crucial for studying dynamic cellular processes. An analog micromirror was adopted to raster the sensor substrate, enabling high-speed imaging. α-Fe2O3 (hematite) thin films synthesized via electrodeposition were used as a robust substrate with high photocurrent and good spatial resolution. The capabilities of this system were demonstrated by monitoring cell responses to permeabilization with Triton X-100. The ability to carry out dynamic functional imaging of multiple cells simultaneously provides improved confidence in the data than could be achieved with the slower electrochemical single-cell imaging techniques described previously. When monitoring pH changes, the PEIS can achieve frame rates of 8 frames per second.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas
16.
ACS Sens ; 5(11): 3568-3575, 2020 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-33112594

RESUMO

Conventional metal oxide semiconductor (MOS) gas sensors have been investigated for decades to protect our life and property. However, the traditional devices can hardly fulfill the requirements of our fast developing mobile society, because the high operating temperatures greatly limit their applications in battery-loaded portable systems that can only drive devices with low power consumption. As ammonia is gaining importance in the production and storage of hydrogen, there is an increasing demand for energy-efficient ammonia detectors. Hence, in this work, a Schottky diode resulting from the contact between zinc oxide nanorods and gold is designed to detect gaseous ammonia at room temperature with a power consumption of 625 µW. The Schottky diode gas sensors benefit from the change of barrier height in different gases as well as the catalytic effect of gold nanoparticles. This diode structure, fabricated without expensive interdigitated electrodes and displaying excellent performance at room temperature, provides a novel method to equip mobile devices with MOS gas sensors.


Assuntos
Nanopartículas Metálicas , Nanotubos , Óxido de Zinco , Amônia , Gases , Ouro , Temperatura
17.
Anal Chem ; 92(14): 9739-9744, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32437169

RESUMO

A new photoelectrochemical imaging method termed scanning electrochemical photometric sensor (SEPS) is proposed in this work. It was derived from light-addressable potentiometric sensor (LAPS) and scanning photoinduced impedance microscopy (SPIM) using a front-side laser illumination at a field-effect structure. When the laser beam scans across the sensor substrate, local photocurrent changes at inversion due to the light absorption of analytes can be recorded. It will be shown that SEPS could be used for label-free living cell imaging with micro-resolution as well as real-time quantitative absorption analysis, which would broaden the applications of traditional LAPS/SPIM from potentiometric/impedance measurements to local optical analysis.


Assuntos
Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Análise de Célula Única/métodos , Escherichia coli
18.
Zhongguo Zhen Jiu ; 39(12): 1279-82, 2019 Dec 12.
Artigo em Chinês | MEDLINE | ID: mdl-31820602

RESUMO

OBJECTIVE: To compare the clinical effect of acupuncture at "three points of iliolumbar" combined with celecoxib and celecoxib alone in the treatment of iliopsoas muscle strain. METHODS: A total of 60 patients with iliopsoas muscle strain were randomly divided into an observation group and a control group, 30 patients in each group. Celecoxib was given orally to both groups, 200 mg once a day for 3 days. On the basis of the above drugs, acupuncture was applied at Yaoda (Extra), Wushu (GB 27), Qiayao (Extra) in the observation group, once a day for 3 days. The Japanese Orthopaedic Association (JOA) score and visual analogue scale (VAS) score were observed and compared before and after treatment, and the content of 5-hydroxytryptamine (5-HT) in serum was detected by enzyme-linked immunosorbent assay (ELISA) before and after treatment in the two groups. RESULTS: After treatment, the JOA scores in the two groups were increased (both P<0.05), and the VAS scores and 5-HT contents were decreased (all P<0.05). The increase of JOA score in the observation group was greater than that in the control group (P<0.05), and the decrease of VAS score and 5-HT content in the observation group was greater than that in the control group (both P<0.05). CONCLUSION: Acupuncture at "three points of ilioumbar" combined with celecoxib in the treatment of iliopsoas muscle strain can improve lumbar function, relieve pain and reduce 5-HT content in serum, which is better than celecoxib alone.


Assuntos
Terapia por Acupuntura , Dor , Humanos , Manejo da Dor , Resultado do Tratamento
19.
Biosens Bioelectron ; 146: 111750, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31605989

RESUMO

Modulated light-activated electrochemistry (MLAE) at semiconductor/liquid interfaces derived from light-addressable potentiometric sensor (LAPS) and light-activated electrochemistry (LAE) for addressable photoelectrochemical sensing has been proposed as a new sensor platform. In this system, a bias voltage is applied to create a depletion layer at the silicon/electrolyte interface. Meanwhile, intensity-modulated light illuminates the movable electrode to generate electron/hole pairs and causes a detectable local AC photocurrent. The AC measurement showed a higher signal-to-noise ratio (SNR) of photocurrents compared to the traditional DC response, while a steeper photocurrent-voltage (I-V) curve than that of LAPS with an insulating layer was obtained. Furthermore, to stabilize and functionalize the silicon substrate, metal-organic framework (MOF) nanoparticles were grown in-situ on the silicon electrode. The successful modification was validated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The AC photocurrent increased as a result of the adsorption of negatively charged DNA, which contributed to the enhancement of the cathodic reduction process at the semiconductor electrodes, indicating a different response mechanism of MLAE from LAPS. The results obtained demonstrate the potential of MOF functionalized MLAE as a robust platform for light-addressable DNA chips with high sensitivity and specificity.


Assuntos
DNA/análise , Estruturas Metalorgânicas/química , Análise de Sequência com Séries de Oligonucleotídeos/instrumentação , Silício/química , Técnicas Biossensoriais/instrumentação , Desenho de Equipamento , Ácidos Nucleicos Imobilizados/química , Luz , Potenciometria/instrumentação
20.
Anal Chim Acta ; 1079: 73-78, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31387721

RESUMO

In this study, we developed a novel bioelectronic taste sensor for the detection of specific bitter substances. A human bitter taste receptor, hT2R4, was efficiently expressed in Escherichia coli (E. coli), which was used as the primary recognition element. A simple and low-cost electrochemical device based on ITO-based electrolyte-semiconductor (ES) structure was innovatively employed as the transducer to assess bacterial metabolic consequences of receptor activation in real time. An apparent increase in extracellular acidification rate was observed, which was resulted from the triggering of hT2R4 receptors by their target ligand of denatonium. The sensor showed dose-dependent responses to denatonuim ranging from 50 nM to 500 nM, while non-bioengineered bacteria without hT2R4 receptors exhibited negligible responses to the same stimulus. In addition, the specificity of the proposed taste biosensor was verified using other typical bitter substances such as quinine and alpha-naphthylthiourea (ANTU). This research provides a simple and inexpensive approach for the construction of bioelectronic taste sensors.


Assuntos
Escherichia coli/genética , Compostos de Amônio Quaternário/análise , Quinina/análise , Receptores Acoplados a Proteínas G/metabolismo , Tioureia/análogos & derivados , Sequência de Bases , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Humanos , Concentração de Íons de Hidrogênio , Compostos de Amônio Quaternário/metabolismo , Quinina/metabolismo , Receptores Acoplados a Proteínas G/genética , Tioureia/análise , Tioureia/metabolismo
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