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1.
Molecules ; 29(10)2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38792214

RESUMO

BACKGROUND: Staphylococcus aureus is a common pathogenic microorganism in humans and animals. Type II NADH oxidoreductase (NDH-2) is the only NADH:quinone oxidoreductase present in this organism and represents a promising target for the development of anti-staphylococcal drugs. Recently, myricetin, a natural flavonoid from vegetables and fruits, was found to be a potential inhibitor of NDH-2 of S. aureus. The objective of this study was to evaluate the inhibitory properties of myricetin against NDH-2 and its impact on the growth and expression of virulence factors in S. aureus. RESULTS: A screening method was established to identify effective inhibitors of NDH-2, based on heterologously expressed S. aureus NDH-2. Myricetin was found to be an effective inhibitor of NDH-2 with a half maximal inhibitory concentration (IC50) of 2 µM. In silico predictions and enzyme inhibition kinetics further characterized myricetin as a competitive inhibitor of NDH-2 with respect to the substrate menadione (MK). The minimum inhibitory concentrations (MICs) of myricetin against S. aureus strains ranged from 64 to 128 µg/mL. Time-kill assays showed that myricetin was a bactericidal agent against S. aureus. In line with being a competitive inhibitor of the NDH-2 substrate MK, the anti-staphylococcal activity of myricetin was antagonized by MK-4. In addition, myricetin was found to inhibit the gene expression of enterotoxin SeA and reduce the hemolytic activity induced by S. aureus culture on rabbit erythrocytes in a dose-dependent manner. CONCLUSIONS: Myricetin was newly discovered to be a competitive inhibitor of S. aureus NDH-2 in relation to the substrate MK. This discovery offers a fresh perspective on the anti-staphylococcal activity of myricetin.


Assuntos
Flavonoides , Testes de Sensibilidade Microbiana , Staphylococcus aureus , Flavonoides/farmacologia , Flavonoides/química , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/enzimologia , Antibacterianos/farmacologia , Antibacterianos/química , NADH Desidrogenase/antagonistas & inibidores , NADH Desidrogenase/metabolismo , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Animais , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/metabolismo , Humanos , Fatores de Virulência/antagonistas & inibidores , Fatores de Virulência/metabolismo
2.
Anal Chem ; 95(49): 18199-18206, 2023 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-38032800

RESUMO

The entropy-driven strategy has been proposed as a milestone work in the development of nucleic acid amplification technology. With the characteristics of an enzyme-free, isothermal, and relatively simple design, it has been widely used in the field of biological analysis. However, it is still a challenge to apply entropy-driven amplification for intracellular target analysis. In this study, a dual-entropy-driven amplification system constructed on the surface of gold nanoparticles (AuNPs) is developed to achieve fluorescence determination and intracellular imaging of microRNA-21 (miRNA-21). The dual-entropy-driven amplification strategy internalizes the fuel chain to avoid the complexity of the extra addition in the traditional entropy-driven amplification strategy. The unique self-locked fuel chain system is established by attaching the three-stranded structure on two groups of AuNPs, where the Cy5 fluorescent label was first quenched by AuNPs. After the target miRNA-21 is identified, the fuel chain will be automatically unlocked, and the cycle reaction will be driven, leading to fluorescence recovery. The self-powered and waste-recycled fuel chain greatly improves the automation and intelligence of the reaction process. Under the optimal conditions, the linear response range of the nanosensor ranges from 5 pM to 25 nM. This nanoreaction system can be used to realize intracellular imaging of miRNA-21, and its good specificity enables it to distinguish tumor cells from healthy cells. The development of the dual-entropy-driven strategy provides an integrated and powerful way for intracellular miRNA analysis and shows great potential in the biomedical field.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , MicroRNAs , MicroRNAs/genética , MicroRNAs/análise , Ouro/química , Entropia , Limite de Detecção , Nanopartículas Metálicas/química , Técnicas Biossensoriais/métodos
3.
Small ; 19(26): e2206791, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37010037

RESUMO

2D materials with atomic thickness display strong gate controllability and emerge as promising materials to build area-efficient electronic circuits. However, achieving the effective and nondestructive modulation of carrier density/type in 2D materials is still challenging because the introduction of dopants will greatly degrade the carrier transport via Coulomb scattering. Here, a strategy to control the polarity of tungsten diselenide (WSe2 ) field-effect transistors (FETs) via introducing hexagonal boron nitride (h-BN) as the interfacial dielectric layer is devised. By modulating the h-BN thickness, the carrier type of WSe2 FETs has been switched from hole to electron. The ultrathin body of WSe2 , combined with the effective polarity control, together contribute to the versatile single-transistor logic gates, including NOR, AND, and XNOR gates, and the operation of only two transistors as a half adder in logic circuits. Compared with the use of 12 transistors based on static Si CMOS technology, the transistor number of the half adder is reduced by 83.3%. The unique carrier modulation approach has general applicability toward 2D logic gates and circuits for the improvement of area efficiency in logic computation.

4.
Analyst ; 148(6): 1384-1385, 2023 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-36810793

RESUMO

Correction for 'A fluorescent aptasensor for ATP based on functional DNAzyme/walker and terminal deoxynucleotidyl transferase-assisted formation of DNA-AgNCs' by Shixin Cai et al., Analyst, 2023, 148, 799-805, https://doi.org/10.1039/D2AN02006H.

5.
Analyst ; 148(4): 799-805, 2023 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-36692002

RESUMO

The development of sensitive adenosine triphosphate (ATP) sensors is imperative due to the tight relationship between the physiological conditions and ATP levels in vivo. Herein, a fluorescent aptasensor for ATP is presented, which adopts a strategy that combines a split aptamer and a DNAzyme/walker with terminal deoxynucleotidyl transferase (TDT)-assisted formation of DNA-AgNCs to realize fluorescence detection of ATP. A multifunctional oligonucleotide sequence is rationally designed, which integrates a split aptamer, a DNAzyme and a DNA walker. Both multifunctional oligonucleotide and its substrate strand are connected to the surface of Fe3O4@Au nanoparticles via Au-S bonds. The existence of ATP can induce the formation of the complete aptamer, and then activate the DNAzyme to circularly cleave the substrate strand, leaving 2',3'-cyclophosphate at the 3'end of the strand. This blocks the polymerization of dCTP to form poly(C) even in the presence of TDT and dCTP, due to the lack of free 3'-OH. In contrast, when ATP is absent, the DNAzyme/walker cannot work and then TDT catalyzes the formation of poly(C) at the free 3'-OH of the substrate strand, which is subsequently utilized as the template to prepare DNA-AgNCs. The fluorescence response derived from AgNCs thus reflects the ATP concentration. Under the optimum conditions, the aptasensor shows a linear response range from 5 nM to 10 000 nM, with a detection limit of 0.27 nM. The level of ATP in human serum can be effectively measured by the aptasensor with good recovery, indicating its application potential in medical samples.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , DNA Catalítico , Nanopartículas Metálicas , Humanos , DNA Catalítico/química , DNA Nucleotidilexotransferase/química , Trifosfato de Adenosina , Ouro/química , Nanopartículas Metálicas/química , Limite de Detecção , DNA/química , DNA Polimerase Dirigida por DNA , Corantes , Aptâmeros de Nucleotídeos/química
6.
Sensors (Basel) ; 23(6)2023 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-36991936

RESUMO

High precision geometric measurement of free-form surfaces has become the key to high-performance manufacturing in the manufacturing industry. By designing a reasonable sampling plan, the economic measurement of free-form surfaces can be realized. This paper proposes an adaptive hybrid sampling method for free-form surfaces based on geodesic distance. The free-form surfaces are divided into segments, and the sum of the geodesic distance of each surface segment is taken as the global fluctuation index of free-form surfaces. The number and location of the sampling points for each free-form surface segment are reasonably distributed. Compared with the common methods, this method can significantly reduce the reconstruction error under the same sampling points. This method overcomes the shortcomings of the current commonly used method of taking curvature as the local fluctuation index of free-form surfaces, and provides a new perspective for the adaptive sampling of free-form surfaces.

7.
Sensors (Basel) ; 22(7)2022 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-35408040

RESUMO

Owing to the significant roles of adenosine triphosphate (ATP) in diverse biological processes, ATP level is used to research and evaluate the physiological processes of organisms. Aptamer-based biosensors have been widely reported to achieve this purpose, which are superior in their flexible biosensing mechanism, with a high sensitivity and good biocompatibility; however, the aptamers currently used for ATP detection have a poor ability to discriminate ATP from adenosine diphosphate (ADP) and adenosine monophosphate (AMP). Herein, an ATP-specific aptamer was screened and applied to construct a fluorescent aptasensor for ATP by using graphene oxide (GO) and strand displacement amplification (SDA). The fluorescence intensity of the sensor is linearly related to the concentration of ATP within 0.1 µM to 25 µM under optimal experimental conditions, and the detection limit is 33.85 nM. The biosensor exhibits a satisfactory specificity for ATP. Moreover, the experimental results indicate that the biosensor can be applied to determine the ATP in human serum. In conclusion, the screened aptamer and the biosensor have promising applications in the determination of the real energy charge level and ATP content in a complex biological system.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Grafite , Trifosfato de Adenosina , Técnicas Biossensoriais/métodos , Corantes Fluorescentes , Humanos , Limite de Detecção
8.
Proc Natl Acad Sci U S A ; 115(37): 9216-9221, 2018 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-30154168

RESUMO

There is mounting concern that social media sites contribute to political polarization by creating "echo chambers" that insulate people from opposing views about current events. We surveyed a large sample of Democrats and Republicans who visit Twitter at least three times each week about a range of social policy issues. One week later, we randomly assigned respondents to a treatment condition in which they were offered financial incentives to follow a Twitter bot for 1 month that exposed them to messages from those with opposing political ideologies (e.g., elected officials, opinion leaders, media organizations, and nonprofit groups). Respondents were resurveyed at the end of the month to measure the effect of this treatment, and at regular intervals throughout the study period to monitor treatment compliance. We find that Republicans who followed a liberal Twitter bot became substantially more conservative posttreatment. Democrats exhibited slight increases in liberal attitudes after following a conservative Twitter bot, although these effects are not statistically significant. Notwithstanding important limitations of our study, these findings have significant implications for the interdisciplinary literature on political polarization and the emerging field of computational social science.


Assuntos
Democracia , Ativismo Político , Mídias Sociais , Feminino , Humanos , Masculino , Estados Unidos
9.
Mikrochim Acta ; 187(5): 304, 2020 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-32350613

RESUMO

A fluorescent aptasensor for Staphylococcus aureus (S. aureus) is designed, which takes advantage of strand displacement amplification (SDA) technology and unique self-assembled DNA hexagonal structure. In the presence of S. aureus, a partially complementary strand of S. aureus aptamer (cDNA) is competitively released from cDNA/aptamer duplex immobilized on magnetic beads due to the affinity of the aptamer for S. aureus. The addition of primer starts the SDA reaction. With the catalysis of Bsm DNA polymerase and Nb.bpu10I endonuclease, a large number of single-stranded DNA (ssDNA) is produced, which induces the opening of a hairpin probe and the subsequent self-assembly to form a hexagonal structure. The staining of the DNA hexagon with SYBR Green I excites the fluorescence signal, which is used for detection. The aptasensor exhibits a broad linear range from 7 to 7 × 107 CFU/mL, with a detection limit of 1.7 CFU/mL for S. aureus. The sensor shows negligible responses to other bacteria. Moreover, the aptasensor has been applied to detect S. aureus in milk samples, and the results demonstrate the general applicability of the sensor and its prospect in systematic detection of S. aureus in food safety control and medicine-related fields. Graphical abstract The presence of S. aureus can be converted to the formation of unique DNA hexagonal structure and subsequent fluorescent signal by the combination of SDA with self-assembly technology.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , DNA de Cadeia Simples/química , Corantes Fluorescentes/química , Staphylococcus aureus/isolamento & purificação , Animais , Sequência de Bases , Contaminação de Alimentos/análise , Limite de Detecção , Leite/microbiologia , Técnicas de Amplificação de Ácido Nucleico , Conformação de Ácido Nucleico , Espectrometria de Fluorescência , Staphylococcus aureus/química
10.
Mikrochim Acta ; 186(12): 843, 2019 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-31768709

RESUMO

Voltammetric detection of the K-ras gene fragment was accomplished through the combined application of (a) a switchable DNA nanostructure, (b) the use of hairpin probe and exonuclease III (Exo III)-assisted signal amplification, (c) a split G-quadruplex, and (d) by exploiting the redox activity of DNAzyme. Three assistant oligonucleotides were designed to construct a DNA tweezer on a gold electrode. It is in "open state" in the absence of K-ras DNA. Then, a hairpin probe was introduced, whose stem-loop structure can be opened through hybridization with the K-ras DNA. Exo III is added which hydrolyzes the complementary region of the hairpin sequence to release a single-stranded rest fragment. The ssDNA hybridizes with the DNA tweezer on the electrode which thereby is switched to the "closed state". This leads to the formation of G-quadruplex due to the shortened distance of the split G-quadruplex-forming sequences in the tweezer. The voltammetric signal of the G-quadruplex-hemin complex, with a peak near -0.3 V vs. Ag/AgCl, is used as the signal output. Under the optimal conditions, the current response in differential pulse voltammetry (DPV) increases linearly with the concentration of K-ras DNA in the range of 0.01-1000 pM, and the detection limit is 2.4 fM. The assay can clearly discriminate K-ras DNA from a single-base mutation. The method has excellent selectivity and was applied to the determination of K-ras DNA in (spiked) serum samples. Graphical abstractSchematic representation of a method for the determination of the K-ras gene fragment through a combination of switchable DNA tweezer, split G-quadruplex, and exonuclease III (ExoIII)-assisted target recycling signal amplification.


Assuntos
Técnicas Biossensoriais/métodos , DNA/sangue , Técnicas Eletroquímicas/métodos , Genes ras , Nanoestruturas/química , Oligodesoxirribonucleotídeos/química , Sequência de Bases , DNA/genética , Técnicas Eletroquímicas/instrumentação , Eletrodos , Quadruplex G , Ouro/química , Hemina/química , Humanos , Sequências Repetidas Invertidas , Limite de Detecção , Mutação , Hibridização de Ácido Nucleico , Oligodesoxirribonucleotídeos/genética
11.
J Steroid Biochem Mol Biol ; 243: 106583, 2024 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-38992392

RESUMO

The oviduct of the Chinese brown frog (Rana dybowskii) expands during pre-brumation rather than the breeding period, exhibiting a special physiological feature. Vitamin A is essential for the proper growth and development of many organisms, including the reproductive system such as ovary and oviduct. Vitamin A is metabolized into retinoic acid, which is crucial for oviduct formation. This study examined the relationship between oviducal expansion and vitamin A metabolism. We observed a significant increase in the weight and diameter of the oviduct in Rana dybowskii during pre-brumation. Vitamin A and its active metabolite, retinoic acid, notably increased during pre-brumation. The mRNA levels of retinol binding protein 4 (rbp4) and its receptor stra6 gene, involved in vitamin A transport, were elevated during pre-brumation compared to the breeding period. In the vitamin A metabolic pathway, the mRNA expression level of retinoic acid synthase aldh1a2 decreased significantly during pre-brumation, while the mRNA levels of retinoic acid α receptor (rarα) and the retinoic acid catabolic enzyme cyp26a1 increased significantly during pre-brumation, but not during the breeding period. Immunohistochemical results showed that Rbp4, Stra6, Aldh1a2, Rarα, and Cyp26a1 were expressed in ampulla region of the oviduct. Western blot results indicated that Aldh1a2 expression was lower, while Rbp4, Stra6, RARα, and Cyp26a1 were higher during pre-brumation compared to the breeding period. Transcriptome analyses further identified differential genes in the oviduct and found enrichment of differential genes in the vitamin A metabolism pathway, providing evidences for our study. These results suggest that the vitamin A metabolic pathway is more active during pre-brumation compared to the breeding period, and retinoic acid may regulate pre-brumation oviductal expansion through Rarα-mediated autocrine/paracrine modulation.

12.
Nutrients ; 16(4)2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38398817

RESUMO

Obesity and its complications constitute a main threat to global human health. The purpose of this investigation was to explore the influences of Clostridium tyrobutyricum (Ct) on lipid metabolism, intestinal barrier function, and intestinal microbiome in obese mice induced by a high-fat diet (HFD). After establishing the obesity model, 107 CFU/mL and 108 CFU/mL C. tyrobutyricum were used to intervene in HFD-fed mice by gavage for six weeks, and indexes related to obesity were measured. In the liver of HFD-fed mice, the results revealed that C. tyrobutyricum reduced liver weight and the levels of triglyceride (TG), total cholesterol (TC), and nonesterified fatty acid (NEFA), along with decreasing red lipid droplets and fat vacuoles. After C. tyrobutyricum intervention, the mRNA expression of peroxisome proliferator-activated receptor-γ (PPARγ) was downregulated, and AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor-α (PPARα), adipose triglyceride lipase (ATGL), and hormone-sensitive lipase (HSL) were upregulated in the liver. Additionally, C. tyrobutyricum alleviated intestinal morphology injury caused by HFD, decreased the expression of tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), and IL-1ß in the colon, and upregulated tight junction protein expression. In addition, 16S rRNA sequencing revealed that C. tyrobutyricum increases the diversity of intestinal microbiota. Overall, C. tyrobutyricum improved HFD-induced lipid metabolism disorders, preserved the intestinal barrier's integrity, and modulated the structure of the intestinal microbiome. These findings provide a novel insight into the role of C. tyrobutyricum as a probiotic in regulating lipid metabolism.


Assuntos
Clostridium tyrobutyricum , Microbioma Gastrointestinal , Humanos , Animais , Camundongos , Dieta Hiperlipídica/efeitos adversos , Metabolismo dos Lipídeos , Microbioma Gastrointestinal/fisiologia , Camundongos Obesos , Função da Barreira Intestinal , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Receptores Ativados por Proliferador de Peroxissomo/metabolismo , Fígado/metabolismo , Obesidade/metabolismo , Camundongos Endogâmicos C57BL
13.
ACS Appl Mater Interfaces ; 16(24): 31473-31479, 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38850243

RESUMO

Scalable micro graphene Hall sensors (µGHSs) hold tremendous potential for highly sensitive and label-free biomagnetic sensing in physiological solutions. To enhance the performance of these devices, it is crucial to optimize frequency-dependent flicker noise to reduce the limit of detection (LOD), but it remains a great challenge due to the large contact resistance at the graphene-metal contact. Here we present a surface modification strategy employing persistent carbene on gold electrodes to reduce the contact resistivity by a factor of 25, greatly diminishing µGHS flicker noise by a factor of 1000 to 3.13 × 10-14 V2/Hz while simultaneously lowering the magnetic LOD SB1/2 to 1440 nT/Hz1/2 at 1 kHz under a 100 µA bias current. To the best of our knowledge, this represents the lowest SB1/2 reported for scalable µGHSs fabricated through wafer-scale photolithography. The reduction in contact noise is attributed to the π-π stacking interaction between the graphene and the benzene rings of persistent carbene, as well as the decrease in the work function of gold as confirmed by Kelvin Probe Force Microscopy. By incorporating a microcoil into the µGHS, we have demonstrated the real-time detection of superparamagnetic nanoparticles (SNPs), achieving a remarkable LOD of ∼528 µg/L. This advancement holds great potential for the label-free detection of magnetic biomarkers, e.g., ferritin, for the early diagnosis of diseases associated with iron overload, such as hereditary hemochromatosis (HHC).

14.
Microbiol Spectr ; 12(1): e0323723, 2024 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-38038452

RESUMO

IMPORTANCE: The use of plant extracts is increasing as an alternative to synthetic compounds, especially antibiotics. However, there is no sufficient knowledge on the mechanisms and potential risks of antibiotic resistance induced by these phytochemicals. In the present study, we found that stable drug resistant mutants of E. coli emerged after repetitive exposure to sanguinarine and demonstrated that the AcrB efflux pump contributed to the emerging of induced and intrinsic resistance of E. coli to this phytochemical. Our results offered some insights into comprehending and preventing the onset of drug-resistant strains when utilizing products containing sanguinarine.


Assuntos
Benzofenantridinas , Proteínas de Escherichia coli , Escherichia coli , Isoquinolinas , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Farmacorresistência Bacteriana Múltipla , Antibacterianos/farmacologia , Antibacterianos/química , Testes de Sensibilidade Microbiana , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética
15.
Adv Sci (Weinh) ; : e2403043, 2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38810136

RESUMO

The optoelectronic resistive random-access memory (RRAM) with the integrated function of perception, storage and intrinsic randomness displays promising applications in the hardware level in-sensor image cryptography. In this work, 2D hexagonal boron nitride based optoelectronic RRAM is fabricated with semitransparent noble metal (Ag or Au) as top electrodes, which can simultaneous capture color image and generate physically unclonable function (PUF) key for in-sensor color image cryptography. Surface plasmons of noble metals enable the strong light absorption to realize an efficient modulation of filament growth at nanoscale. Resistive switching curves show that the optical stimuli can impede the filament aggregation and promote the filament annihilation, which originates from photothermal effects and photogenerated hot electrons in localized surface plasmon resonance of noble metals. By selecting noble metals, the optoelectronic RRAM array can respond to distinct wavelengths and mimic the biological dichromatic cone cells to perform the color perception. Due to the intrinsic and high-quality randomness, the optoelectronic RRAM can produce a PUF key in every exposure cycle, which can be applied in the reconfigurable cryptography. The findings demonstrate an effective strategy to build optoelectronic RRAM for in-sensor color image cryptography applications.

16.
Nanoscale ; 15(9): 4309-4316, 2023 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-36756937

RESUMO

Two-dimensional (2D) materials have become potential resistive switching (RS) layers to prepare emerging non-volatile memristors. The atomically thin thickness and the highly controllable defect density contribute to the construction of ultimately scaled memory cells with stable switching behaviors. Although the conductive bridge random-access memory based on 2D hexagonal boron nitride has been widely studied, the realization of RS completely relying on vacancies in 2D materials has performance superiority. Here, we synthesize carbon-doped h-BN (C-h-BN) with a certain number of defects by controlling the weight percentage of carbon powder in the source. These defects can form a vacancy-based conductive filament under an applied electric field. The memristor displays bipolar non-volatile memory with a low SET voltage of 0.85 V and shows a long retention time of up to 104 s at 120 °C. The response times of the SET and RESET process are less than 80 ns and 240 ns, respectively. The current mapping by conductive atomic force microscopy demonstrates the electric-field-induced current tunneling from defective sites of the C-h-BN flake, revealing the defect-based RS in the C-h-BN memristor. Moreover, C-h-BN with excellent flexibility can be applied to wearable devices, maintaining stable RS performance in a variety of bending environments and after multiple bending cycles. The vacancy-based 2D memristor provides a new strategy for developing ultra-scaled memory units with high controllability.

17.
Anal Chim Acta ; 1198: 339559, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-35190125

RESUMO

As most single tumor markers have low sensitivity or specificity, the joint detection of multiple tumor biomarkers is helpful to improve the positive rate and specificity of early diagnosis. To establish a sensitive, specific, and rapid screening method for ovarian cancer, two enzyme-free logic gates were developed to realize the joint detection of carbohydrate antigen 125 (CA125) and carcinoembryonic antigen (CEA). G-quadruplex with peroxidase activity was used as a chromogenic catalyst in this colorimetric diagnosis. For NOR gate, in the absence of CEA and CA125, template DNA (Tem-DNA), CEA aptamer with half of the G-quadruplex sequence (CEA-apt), and CA125 aptamer with the other half of the G-quadruplex sequence (CA125-apt) form a double-stranded DNA equipped with one G-quadruplex structure which can strongly combine with hemin to obtain the peroxidase-like activity; here, the output of this NOR gate is set as 1, which could exclude the risk of ovarian cancer. For AND gate, CEA-apt and CA125-apt are separated from magnetic beads in the co-existence of the dual biomarkers. After adding Tem-DNA, the G-quadruplex structure constructs with hemin to exhibit the output as 1, presenting a high risk of ovarian cancer. Under the optimized condition, this novel assay can not only show a sharp color difference between physiological state and pathological state, but also be employed for the quantitative analysis of every single biomarker. The linear detection range and detection limit for CEA are 5-500 ng mL-1 and 0.88 ng mL-1, while they are for CA125 are 35-500 U mL-1 and 0.91 U mL-1, respectively. Moreover, the established approach was successfully applied in detecting CA125 and CEA in human serum samples, which provides great promise in the fields of clinical examination and disease diagnosis.


Assuntos
Quadruplex G , Neoplasias Ovarianas , Biomarcadores Tumorais , Antígeno Ca-125 , Antígeno Carcinoembrionário , Hemina/química , Humanos , Neoplasias Ovarianas/diagnóstico , Neoplasias Ovarianas/genética
18.
Food Chem ; 367: 130754, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34384983

RESUMO

N-acetylneuraminic acid (Neu5Ac) is widely spread in many biologically significant glycans of mammals, commonly as a terminal α-glycoside. It is of great significance to develop analytical techniques for detection of Neu5Ac. Herein, a high-sensitive fluorescent biosensor for Neu5Ac has been developed based on FRET between CdSe/ZnS quantum dots (QDs) and BHQ2, as well as exonuclease III (Exo III)-assisted recycling amplification strategy. Employing the specially designed three-level FRET systems and fluorescent signal recovery mechanism, together with five-step recycling signal amplification chain reactions, an ultralow detection limit of 24 fM was achieved. Meanwhile, good linear response ranges within 0.2-12.5 pM and 12.5-1000 pM were founded. The assay has excellent performance in real sample detection, and thus offers great potential for detection of sialic acids modified glycans/lipids in the fields of medical diagnosis and food testing.


Assuntos
Compostos de Cádmio , Pontos Quânticos , Compostos de Selênio , Animais , DNA , Exodesoxirribonucleases , Transferência Ressonante de Energia de Fluorescência , Limite de Detecção , Ácidos Siálicos , Sulfetos , Compostos de Zinco
19.
ACS Appl Mater Interfaces ; 14(39): 44614-44621, 2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-36136123

RESUMO

An artificial synapse is essential for neuromorphic computing which has been expected to overcome the bottleneck of the traditional von-Neumann system. Memristors can work as an artificial synapse owing to their tunable non-volatile resistance states which offer the capabilities of information storage, processing, and computing. In this work, memristors based on two-dimensional (2D) MXene Ti3C2 nanosheets sandwiched by Pt electrodes are investigated in terms of resistive switching (RS) characteristics, synaptic functions, and neuromorphic computing. Digital and analog RS behaviors are found to coexist depending on the magnitude of operation voltage. Digital RS behaviors with two resistance states possessing a large switching ratio exceeding 103 can be achieved under a high operation voltage. Analog RS behaviors with a series of resistance states exhibiting a gradual change can be observed at a relatively low operation voltage. Furthermore, artificial synapses can be implemented based on the memristors with the basic synaptic functions, such as long-term plasticity of long-term potentiation and depression and short-term plasticity of the paired-pulse facilitation and depression. Moreover, the "learning-forgetting" experience is successfully emulated based on the artificial synapses. Also, more importantly, the artificial synapses can construct an artificial neural network to implement image recognition. The coexistence of digital and analog RS behaviors in the 2D Ti3C2 nanosheets suggests the potential applications in non-volatile memory and neuromorphic computing, which is expected to facilitate simplifying the manufacturing complexity for complex neutral systems where analog and digital switching is essential for information storage and processing.

20.
Food Res Int ; 155: 111003, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35400418

RESUMO

Present study was conducted to comprehensively investigate the protective effects of galactooligosaccharides (GOS, 100%) against LPS-induced intestinal barrier damages, and the regulatory effect for intestinal microbes. Results showed that GOS intervention restored villi (jejunum and ileum) integrity, which were atrophic and broken in LPS-challenged mice. Electron microscopy, western blotting and immunofluorescence analysis exhibited that mice administrated with GOS showed higher expression of tight junction, which was confirmed in IPEC-J2 cells model. Meanwhile, the GOS increased the secretion of mucin and SIgA, as well as it alleviated inflammatory response caused by LPS in NF-κB dependent way. Administration of GOS could also increase the relative abundances of several specific friendly bacteria, and enhance the adaptability of intestinal microbiota. Collectively, these results indicated the potential of GOS for protecting intestine from injuries caused by stress as LPS challenge.


Assuntos
Microbioma Gastrointestinal , Animais , Linhagem Celular , Intestinos , Lipopolissacarídeos , Camundongos , Substâncias Protetoras
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