Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 83
Filter
1.
Analyst ; 149(14): 3850-3856, 2024 Jul 08.
Article in English | MEDLINE | ID: mdl-38855851

ABSTRACT

Aflatoxin B1 (AFB1), classified as a class I carcinogen, is a widespread mycotoxin that poses a serious threat to public health and economic development, and the food safety problems caused by AFB1 have aroused worldwide concern. The development of accurate and sensitive methods for the detection of AFB1 is significant for food safety monitoring. In this work, a sandwich-type photoelectrochemical (PEC) biosensor for AFB1 detection was constructed on the basis of an aptamer-antibody structure. A good photocurrent response was obtained due to the sensitization of In2S3 by Ru(bpy)32+. In addition, this sandwich-type sensor constructed by modification with the antibody, target detector, and aptamer layer by layer attenuated the migration hindering effect of photogenerated carriers caused by the double antibody structure. The aptamer and antibody synergistically recognized and captured the target analyte, resulting in more reliable PEC response signals. CdSe@CdS QDs-Apt were modified as a signal-off probe onto the sensor platform to quantitatively detect AFB1 with a "signal-off" response, which enhanced the sensitivity of the sensor. The PEC biosensor showed a linear response range from 10-12 to 10-6 g mL-1 with a detection limit of 0.023 pg mL-1, providing a feasible approach for the quantitative detection of AFB1 in food samples.


Subject(s)
Aflatoxin B1 , Aptamers, Nucleotide , Biosensing Techniques , Electrochemical Techniques , Limit of Detection , Aflatoxin B1/analysis , Aflatoxin B1/immunology , Biosensing Techniques/methods , Aptamers, Nucleotide/chemistry , Electrochemical Techniques/methods , Electrochemical Techniques/instrumentation , Quantum Dots/chemistry , Food Contamination/analysis , Cadmium Compounds/chemistry , Antibodies, Immobilized/immunology , Antibodies, Immobilized/chemistry , Photochemical Processes , Sulfides/chemistry , Selenium Compounds/chemistry , Organometallic Compounds
2.
Angew Chem Int Ed Engl ; : e202406677, 2024 Jun 02.
Article in English | MEDLINE | ID: mdl-38825572

ABSTRACT

The microtubule-associated protein tau participates in neurotransmission regulation via its interaction with synaptic vesicles (SVs). The precise nature and mechanics of tau's engagement with SVs, especially regarding alterations in vesicle dynamics, remain a matter of discussion. We report an electrochemical method using a synapse-mimicking nanopipette to monitor vesicle dynamics induced by tau. A model vesicle of ~30 nm is confined within a lipid-modified nanopipette orifice with a comparable diameter to mimic the synaptic lipid environment. Both tau and phosphorylated tau (p-tau) present two-state dynamic behavior in this biomimetic system, showing typical ionic current oscillation, induced by lipid-tau interaction. The results indicate that p-tau has a stronger affinity to the lipid vesicles in the confined environment, blocking the vesicle movement to a higher degree. Taken together, this method bridges a gap for sensing synaptic vesicle dynamics in a confined lipid environment, mimicking vesicle movement near the synaptic membrane. These findings contribute to understanding how different types of tau protein regulate synaptic vesicle motility and to underlying its functional and pathological behaviours in disease.

3.
Zhongguo Zhong Yao Za Zhi ; 49(10): 2680-2688, 2024 May.
Article in Chinese | MEDLINE | ID: mdl-38812168

ABSTRACT

Methyleugenol is one of the main active constituents in the volatile oil of the traditional Chinese medicine Asari Radix et Rhizoma. It possesses various pharmacological effects such as analgesic, anesthetic, and anti-inflammatory properties. In biosynthesis, the initial precursor phenylalanine is finally converted into methyleugenol through a series of intermediate compounds including coniferyl acid, courmaryl acid, caffeic acid, ferulic acid/ferulic-CoA, coniferyl aldehyde, conferyl alcohol, cnfiferyl acetate, and eugenol/isoeugenol, which are produced through catalysis of a large number of enzymes. Eugenol O-methyltransferase(EOMT) is one of the key enzymes in the biosynthesis pathway, capable of methylating eugenol on the para-site hydroxyl group of the benzene ring, thereby generating methyleugenol. Here, an(iso)eugenol O-methyltransferase(IEMT) gene was cloned for the first time from Asarum siebo-ldii, holding an open reading frame that consisted of 1 113 bp and encoded a protein containing 370 amino acid residues. Bioinformatics analysis results showed that this protein was equipped with the characteristic structural domains of methyltransferases such as S-adenosylmethionine(SAM) binding sites and dimerization domains. The prokaryotic expression recombinant plasmid pET28a(+)-AsIEMT was constructed, and the candidate protein was induced and purified. In vitro enzyme assays confirmed that AsIEMT had dual functions. The enzyme could catalyze the production either of methyleugenol from eugenol or of methylisoeugenol from isoeugenol, although the latter was more prevalent. When isoeugenol was used as the substrate, the kinetics parameters K_m and V_(max) of catalytic reaction were(0.90±0.06) mmol·L~(-1) and(1.32±0.04)nmol·s~(-1)·mg~(-1), respectively. This study expanded our understandings of critical enzyme genes involved in phenylpropanoid metabolic pathways, and would facilitate the elucidation of quality formation mechanisms of the TCM Asari Radix et Rhizoma.


Subject(s)
Asarum , Eugenol , Methyltransferases , Methyltransferases/genetics , Methyltransferases/chemistry , Methyltransferases/metabolism , Eugenol/analogs & derivatives , Eugenol/metabolism , Eugenol/chemistry , Asarum/genetics , Asarum/chemistry , Asarum/enzymology , Plant Proteins/genetics , Plant Proteins/metabolism , Plant Proteins/chemistry , Phylogeny , Amino Acid Sequence , Cloning, Molecular
4.
Angew Chem Int Ed Engl ; : e202404170, 2024 May 23.
Article in English | MEDLINE | ID: mdl-38781086

ABSTRACT

The key to rationally and rapidly designing high-performance materials is the monitoring and comprehension of dynamic processes within individual particles in real-time, particularly to gain insight into the anisotropy of nanoparticles. The intrinsic property of nanoparticles typically varies from one crystal facet to the next under realistic working conditions. Here, we introduce the operando collision electrochemistry to resolve the single silver nanoprisms (Ag NPs) anisotropy in photoelectrochemistry. We directly identify the effect of anisotropy on the plasmonic-assisted electrochemistry at the single NP/electrolyte interface. The statistical collision frequency shows that heterogeneous diffusion coefficients among crystal facets facilitate Ag NPs to undergo direction-dependent mass transfer toward the gold ultramicroelectrode. Subsequently, the current amplitudes of transient events indicate that the anisotropy enables variations in dynamic interfacial electron transfer behaviors during photothermal processes. The results presented here demonstrate that the measurement precision of collision electrochemistry can be extended to the sub-nanoparticle level, highlighting the potential for high-throughput material screening with comprehensive kinetics information at the nanoscale.

5.
J Nat Med ; 78(3): 633-643, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38704807

ABSTRACT

Hepatocellular carcinoma (HCC) is a malignant tumor with extremely high mortality. The tumor microenvironment is the "soil" of its occurrence and development, and the inflammatory microenvironment is an important part of the "soil". Bile acid is closely related to the occurrence of HCC. Bile acid metabolism disorder is not only directly involved in the occurrence and development of HCC but also affects the inflammatory microenvironment of HCC. Yinchenhao decoction, a traditional Chinese medicine formula, can regulate bile acid metabolism and may affect the inflammatory microenvironment of HCC. To determine the effect of Yinchenhao decoction on bile acid metabolism in mice with HCC and to explore the possible mechanism by which Yinchenhao decoction improves the inflammatory microenvironment of HCC by regulating bile acid metabolism, we established mice model of orthotopic transplantation of hepatocellular carcinoma. These mice were treated with three doses of Yinchenhao decoction, then liver samples were collected and tested. Yinchenhao decoction can regulate the disorder of bile acid metabolism in liver cancer mice. Besides, it can improve inflammatory reactions, reduce hepatocyte degeneration and necrosis, and even reduce liver weight and the liver index. Taurochenodeoxycholic acid, hyodeoxycholic acid, and taurohyodeoxycholic acid are important molecules in the regulation of the liver inflammatory microenvironment, laying a foundation for the regulation of the liver tumor inflammatory microenvironment based on bile acids. Yinchenhao decoction may improve the inflammatory microenvironment of mice with HCC by ameliorating hepatic bile acid metabolism.


Subject(s)
Bile Acids and Salts , Carcinoma, Hepatocellular , Drugs, Chinese Herbal , Liver Neoplasms , Tumor Microenvironment , Animals , Drugs, Chinese Herbal/pharmacology , Drugs, Chinese Herbal/therapeutic use , Carcinoma, Hepatocellular/drug therapy , Carcinoma, Hepatocellular/metabolism , Mice , Bile Acids and Salts/metabolism , Tumor Microenvironment/drug effects , Liver Neoplasms/drug therapy , Liver Neoplasms/metabolism , Male , Liver/drug effects , Liver/metabolism , Liver/pathology , Inflammation/drug therapy , Inflammation/metabolism
6.
J Colloid Interface Sci ; 665: 144-151, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38520931

ABSTRACT

Electrochemiluminescence (ECL) biosensors provide a convenient and high sensitivity method for early disease diagnosis. However, creating luminophore arrays relying on powerful ECL signals remains a daunting task. Porphyrin-centered metal organic frameworks (MOFs) exhibit remarkable potential in ECL sensing applications. In this paper, based on a simple one-pot synthesis method, PCN-222@Ag NPs doped with CeO2 was synthesized to enhance the ECL performance. Due to the strong catalytic ability of CeO2, the ECL signal strength of the new material PCN-222@CeO2@Ag NPs is much higher than that of the PCN-222@Ag NPs and PCN-222. The luminous properties of PCN-222@CeO2@Ag NPs become more intense and stable due to the excellent electronic conductivity of Ag NPs. Based on the fact that CuS@PDA composite can quench the ECL signal of PCN-222@CeO2@Ag NPs, we constructed a novel sandwich ECL immune sensor for the detection of phosphorylated Tau 181 (p-Tau-181) protein. The ECL sensor has a great linear relationship with p-Tau-181 protein concentration, ranging from 1 pg/mL to 100 ng/mL. The detection limit is as low as 0.147 pg/mL. This work provides new ideas for developing sensitive ECL sensors for the p-Tau-181 protein, the marker of Alzheimer's disease.


Subject(s)
Biosensing Techniques , Metal Nanoparticles , Luminescent Measurements/methods , Biosensing Techniques/methods , Electrochemical Techniques/methods , Limit of Detection
7.
Chem Commun (Camb) ; 59(100): 14847-14850, 2023 Dec 14.
Article in English | MEDLINE | ID: mdl-38015452

ABSTRACT

An ultrasensitive photoelectrochemical (PEC) aptasensor was originally designed by using ZnIn2S4/ReS2 as a photoactive material and AgInS2 as a signal amplifier. The signal amplifier AgInS2 was incubated on the terminal of H-DNA (immobilized on the ZnIn2S4/ReS2/FTO surface), leading to an enhanced photocurrent response. Then, due to the introduction of DNA2, the formation of a double-stranded structure caused AgInS2 to keep away from the electrode surface, and the photocurrent was reduced. In the presence of kanamycin, DNA2 was released from the system due to the competition relationship, and a restored photocurrent response was obtained. The combination of ZnIn2S4/ReS2 and AgInS2 accelerated the electron transfer and enhanced the separation efficiency of photogenerated electron-hole pairs, resulting in an improved performance of the PEC aptasensor, which was capable of accurate and sensitive detection of kanamycin in actual samples.


Subject(s)
Aptamers, Nucleotide , Biosensing Techniques , Kanamycin , Electrochemical Techniques/methods , Biosensing Techniques/methods , Electron Transport , Electrodes , Limit of Detection , Aptamers, Nucleotide/chemistry
8.
Analyst ; 148(4): 772-779, 2023 Feb 13.
Article in English | MEDLINE | ID: mdl-36661384

ABSTRACT

In this study, for the first time, a silver-based metal-organic framework (Ag-MOF) was synthesized and used as the electrochemiluminescence (ECL) emitter for building an ECL sensor. After modification with chitosan (CS) and gold nanoparticles (Au NPs), the ECL stability of Ag-MOF was improved. To detect mercury ions, a biosensor was constructed using the mercury ion aptamer and steric effect of streptavidin. First, the capture strand (cDNA) with terminal-modified sulfhydryl group was attached to the electrode surface by the Au-S bond. Then, the mercury-ion aptamer (Apt-Hg) modified with biotin was anchored to the electrode by complementary pairing with cDNA. Streptavidin (SA) could be fixed on the electrode by linking with biotin, thereby reducing the ECL signal. However, in the presence of mercury ions, the aptamer was removed and streptavidin could not be immobilized on the electrode. Hence, the ECL signal of the sensor increased with the concentration of mercury ions, which was linear in the range from 1 µM to 300 fM. The detection limit could reach 66 fM (S/N = 3). The sensor provided a new method for the detection of mercury ions.


Subject(s)
Aptamers, Nucleotide , Biosensing Techniques , Mercury , Metal Nanoparticles , Biotin/chemistry , Streptavidin/chemistry , Silver , DNA, Complementary , Gold/chemistry , Electrochemical Techniques/methods , Metal Nanoparticles/chemistry , Luminescent Measurements/methods , Aptamers, Nucleotide/chemistry , Ions , Biosensing Techniques/methods , Limit of Detection
9.
Talanta ; 253: 123601, 2023 Feb 01.
Article in English | MEDLINE | ID: mdl-36126520

ABSTRACT

A novel photoelectrochemical (PEC) biosensor based on b-TiO2/CdS:Eu/Ti3C2 heterojunction was developed for ultrasensitive determination of miRNA-21. In this device, the b-TiO2/CdS:Eu/Ti3C2 heterojunction with excellent energy level arrangement effectively facilitated photoelectric conversion efficiency and accelerated the separation of the photogenerated electron hole pairs, which because that the structure of heterojunction overcomes the drawbacks of single material, such as narrow light absorption range, wide band gap, short carrier lifetime, etc., improves light utilization, extends the lifetime of photogenerated electron hole pairs, and promotes electron transfer. Herein, hairpin DNA1 (H1) decorated on the b-TiO2/CdS:Eu/Ti3C2 electrode surface by Cd-S bonds, after H2/miRNA-21 heterduplex was introduced, the strand-displacement reaction (SDR) was triggered between H1 and H2/miRNA-21, accordingly, miRNA-21 was discharged from the H2/miRNA-21 heterduplex, forming the H1/H2 duplex, and the reuse of miRNA-21 was realized. As a signal amplification factor, the signal amplification factor H3-CdSe was hybridized with H1/H2 duplex, which greatly enhanced the sensitivity of the PEC biosensor. Under optimal conditions, the designed PEC biosensor displayed outstanding sensitivity, selectivity and stability with a wide liner range from 1.0 µM to 10.0 fM and a low detection limit of 3.3 fM. The preparation of the optoelectronic material affords a new direction for the progress of heterojunction photovoltaic materials and the construction of the proposed biosensor also provides a new thought for the PEC detection of human miRNA-21 with superior performance. Simultaneously, the established biosensor exhibiting tremendous possibility for detecting other biomarkers and biomolecules in clinical diagnosis fields.


Subject(s)
Biosensing Techniques , MicroRNAs , Titanium , Humans , Electrodes , Photochemistry
10.
Mikrochim Acta ; 189(7): 264, 2022 07 01.
Article in English | MEDLINE | ID: mdl-35776207

ABSTRACT

The electrochemiluminescence and resonance energy transfer (ECL-RET) method was adopted to detect miRNAs, in which the two-dimensional Ti3C2 Mxenes with high surface area modified with CdS:W nanocrystals (CdS:W NCs) were used as ECL signal emitter. Mxenes with a specific surface area of 5.2755 m2/g carried more emitters and promote ECL intensity. As an energy acceptor, BiOCl nanosheets (BiOCl NSs) have a wide UV-Vis absorption peak in the range 250 nm-700 nm, including the emission band of CdS:W NCs with 520 nm emission wavelength. Hence, BiOCl NSs are covalently bound to hairpin DNA 2 by amide bond to quench the ECL signal of CdS:W NCs. In the presence of miRNA-141, the hairpin DNA 1 modified on the GCE was unfold and then paired with hairpin DNA 2 to release miRNA-141 and quench the signal of the ECL biosensor. Then, the concentration signal of miRNA-141 was amplified by catalytic hairpin assembly. The novel specific biosensor demonstrated a satisfactory linear relationship with miRNA-141 in the range 0.6 pM to 4000 pM; the detection limit was as low as 0.26 pM (3 s/m) under the potential of 0 ~ -1.3 V and showed outstanding RSD of 1.19%. The findings of the present work with high accuracy and sensitivity will be of positive significance for the clinical diagnosis of miRNA in the future work. The construction process of the biosensor and electrochemiluminescence mechanism.


Subject(s)
Electrochemical Techniques , MicroRNAs , DNA/chemistry , DNA/genetics , Electrochemical Techniques/methods , Energy Transfer , Luminescent Measurements/methods , MicroRNAs/genetics
11.
Article in English | MEDLINE | ID: mdl-35537183

ABSTRACT

In this work, a two-dimensional (2D) MOF sheet with electrochemiluminescence (ECL) activity is prepared with Ti3C2Tx MXene as the metal precursor and the meso-tetra(4-carboxyl-phenyl) porphyrin (H2TCPP) as the organic ligand. The atomically thin 2D Ti3C2Tx MXene is utilized as the metal precursor and soft template to produce the MOF with a 2D nanosheet morphology (Ti3C2Tx-PMOF). Ti3C2Tx MXene is a kind of strong electron acceptor, which can deprotonate H2TCPP due to the high electronegativity and low work function of its terminal atoms. The deprotonated H2TCPP continues to bind with Ti atoms to form the 2D MOF sheet. The ECL activity is inherited from H2TCPP and stabilized by introducing Ag NPs. Then, we construct an ECL biosensor based on the Ag NPs/Ti3C2Tx-PMOF to detect the oral cancer overexpressed 1 (ORAOV 1). A bipedal three-dimensional DNA walker strategy is adopted to further improve the biosensor sensitivity. As expected, the biosensor exhibits sterling sensitivity and selectivity. The ECL biosensor responds linearly to ORAOV 1 concentrations in the range of 10 fM-1 nM, and the detection limit is as low as 3.3 fM (S/N = 3). It means that Ag NPs/Ti3C2Tx-PMOF is a potential material to design and construct the high-performance ECL biosensors.

12.
Folia Microbiol (Praha) ; 67(3): 517-522, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35194755

ABSTRACT

Actinomycete strain YIM PH20352, isolated from the rhizosphere soil sample of Panax notoginseng collected in WenShang, Yunnan Province, China, exhibited antifungal activity against some phytopathogenic fungi. The structures of bioactive molecules, isolated from the ethyl acetate extract of the fermentation broth of the strain, were identified as rabelomycin (1) and dehydrorabelomycin (2) based on extensive spectroscopic analyses. Compound 1 exhibited antifungal activity against four tested root-rot pathogens of the Panax notoginseng including Plectosphaerella cucumerina, Alternaria panax, Fusarium oxysporum, and Fusarium solani with the MIC values at 32, 64, 128, and 128 µg/mL, respectively. Compound 2 exhibited antifungal activity against F. oxysporum, P. cucumerina, F. solani, and A. panax with the MIC values at 64, 64, 128, and 128 µg/mL, respectively. Based on the phylogenetic analyses, the closest phylogenetic relative of strain YIM PH20352 is Streptomyces cellulosae NBRC 13027 T (AB184265) (99.88%), so strain YIM PH20352 was identified as Streptomyces cellulosae. To the best of our knowledge, this is the first report of rabelomycin and rabelomycin-type antibiotics from Streptomyces cellulosae and their antifungal activity against root-rot pathogens of the Panax notoginseng.


Subject(s)
Panax notoginseng , Soil , Anthraquinones , Antifungal Agents/chemistry , China , Fungi , Panax notoginseng/microbiology , Phylogeny , Plant Diseases/microbiology , Streptomyces
13.
World J Clin Cases ; 9(23): 6591-6607, 2021 Aug 16.
Article in English | MEDLINE | ID: mdl-34447808

ABSTRACT

Beta-carotene is an important natural pigment that is very beneficial to human health. It is widely found in vegetables and fruits. The three main functions are antioxidant effects, cell gap junction-related functions and immune-related functions. Because of its diverse functions, beta-carotene is believed to prevent and treat many chronic diseases. Gastric cancer is one of the most important diseases it can treat. Gastric cancer is a type of cancer with a high incidence. Its etiology varies, and the pathogenesis is complex. Gastric cancer seriously affects human health. The role of beta-carotene, a natural nutrient, in gastric cancer has been explored by many researchers, including molecular mechanisms and epidemiological studies. Molecular studies have mainly focused on oxidative stress, cell cycle, signal transduction pathways and immune-related mechanisms of beta-carotene in gastric cancer. Many epidemiological surveys and cohort studies of patients with gastric cancer have been conducted, and the results of these epidemiological studies vary due to the use of different research methods and analysis of different regions. This paper will summarize the results of these studies, mainly in terms of molecular mechanisms and epidemiological research results, which will provide a systematic basis for future studies of the treatment and prognosis of gastric cancer. This paper will help researchers identify new research directions.

14.
Talanta ; 233: 122546, 2021 Oct 01.
Article in English | MEDLINE | ID: mdl-34215049

ABSTRACT

In this paper, hydrothermal method was used for the synthesis of SnO2 quantum dots (QDs). The prepared SnO2 QDs have a uniform particle size distribution and good electrochemiluminescence (ECL) property. Then the prepared SnO2 QDs was combined with graphene-like carbon nitride (g-C3N4) through chitosan to form SnO2/chitosan/g-C3N4 nanocomposite and used for detecting the lincomycin. The characteristics of SnO2/chitosan/g-C3N4 nanocomposite were presented by transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS), and the analytical results proving that the nanocomposite was prepared successfully. In this strategy, the SnO2/chitosan/g-C3N4 nanocomposite was acted as the substrate of aptasensor. Then, SH-DNA (aptamer DNA) was assembled on the surface of electrode, after 6-mercaptohexanol (MCH) blocked the unbound sites of the electrode surface, ferrocene-DNA (Fc-DNA) was incubated on the electrode surface through base complementation with aptamer DNA. In the absence of lincomycin, due to the low conductivity of Fc-DNA and the photo-excited energy electron transfer, the ECL signal was quenched. In the presence of lincomycin, the aptamer DNA was specific binding with lincomycin, and ferrocene-DNA (Fc-DNA) was detached from the surface of aptasensor electrode, generating an obviously enhancement of ECL signal. To ensure the accuracy of the data, each electrode runs continuously for 3600 s. Under optimal experimental conditions, the detection range of the aptasensor was 0.10 ng mL-1 - 0.10 mg mL-1, and the detection limit was 0.028 ng mL-1. In addition, the aptasensor has good stability and reproducibility, and also provided a hopeful device for all kinds of other protein target.


Subject(s)
Aptamers, Nucleotide , Biosensing Techniques , Chitosan , Nanocomposites , Electrochemical Techniques , Lincomycin , Luminescent Measurements , Reproducibility of Results
15.
Int Immunopharmacol ; 96: 107790, 2021 Jul.
Article in English | MEDLINE | ID: mdl-34162153

ABSTRACT

Selenium (Se) is an essential trace chemical element that is widely distributed worldwide. Se exerts its immunomodulatory and nutritional activities in the human body in the form of selenoproteins. Se has increasingly appeared as a potential trace element associated with many human diseases, including hepatocellular carcinoma (HCC). Recently, increasing evidence has suggested that Se and selenoproteins exert their immunomodulatory effects on HCC by regulating the molecules of oxidative stress, inflammation, immune response, cell proliferation and growth, angiogenesis, signaling pathways, apoptosis, and other processes in vitro cell studies and in vivo animal studies. Se concentrations are generally low in tissues of patients with HCC, such as blood, serum, scalp hair, and toenail. However, Se concentrations were higher in HCC patient tissues after Se supplementation than before supplementation. This review summarizes the significant relationship between Se and HCC, and details the role of Se as a novel immunomodulatory or immunotherapeutic approach against HCC.


Subject(s)
Carcinoma, Hepatocellular/drug therapy , Immunologic Factors/therapeutic use , Liver Neoplasms/drug therapy , Selenium/therapeutic use , Selenoproteins/immunology , Animals , Carcinoma, Hepatocellular/immunology , Humans , Immunologic Factors/pharmacology , Liver Neoplasms/immunology , Selenium/pharmacology
16.
J Am Chem Soc ; 143(4): 1768-1772, 2021 02 03.
Article in English | MEDLINE | ID: mdl-33482056

ABSTRACT

The classic Fokin mechanism of the CuAAC reaction of terminal alkynes using a variety of Cu(I) catalysts is well-known to include alkyne deprotonation involving a bimetallic σ,π-alkynyl intermediate. In this study, we have designed a CNT-supported atomically precise nanocluster Au4Cu4 (noted Au4Cu4/CNT) that heterogeneously catalyzes the CuAAC reaction of terminal alkynes without alkyne deprotonation to a σ,π-alkynyl intermediate. Therefore, three nanocluster-π-alkyne intermediates [Au4Cu4(π-CH≡C-p-C6H4R)], R = H, Cl, and CH3, have been captured and characterized by MALDI-MS. This Au4Cu4/CNT system efficiently catalyzed the CuAAC reaction of terminal alkynes, and internal alkynes also undergo this reaction. DFT results further confirmed that HC≡CPh was activated by π-complexation with Au4Cu4, unlike the classic dehydrogenation mechanism involving the bimetallic σ,π-alkynyl intermediate. On the other hand, a Cu11/CNT catalyst was shown to catalyze the reaction of terminal alkynes following the classic deprotonation mechanism, and both Au11/CNT and Cu11/CNT catalysts were inactive for the AAC reaction of internal alkynes under the same conditions, which shows the specificity of Au4Cu4 involving synergy between Cu and Au in this precise nanocluster. This will offer important guidance for subsequent catalyst design.

17.
Analyst ; 146(6): 1835-1838, 2021 Mar 21.
Article in English | MEDLINE | ID: mdl-33502405

ABSTRACT

Here, we proposed a ratiometric electrochemiluminescent (ECL) strategy in spatially multiplied ECL systems. By the specific recognition of hyaluronic acid with proteoglycan CD44 and epidermal growth factor with epidermal growth factor receptor on the cell surface, the cells were labelled with potential-resolved ECL probes, namely Ru(bpy)32+ and g-C3N4, respectively. The as-proposed cytosensor provides a multichannel ECL protocol to improve the throughput, which may push the application of ECL for the cellular immunoanalysis.


Subject(s)
Biosensing Techniques , Luminescent Measurements , Aniline Compounds , Electrodes , Hydrogels
18.
Rev Sci Instrum ; 92(12): 121301, 2021 Dec 01.
Article in English | MEDLINE | ID: mdl-34972456

ABSTRACT

Nanopore measurement has advanced in single-molecule analysis by providing a transient time and confined space window that only allows one interested molecule to exist. By optimization and integration of the electrical and optical analysis strategies in this transient window, the acquisition of comprehensive information could be achieved to resolve the intrinsic properties and heterogeneity of a single molecule. In this work, we present a roadmap to build a unified optical and electrochemical synchronous measurement platform for the research of a single molecule. We design a low-cost ultralow-current amplifier with low noise and high-bandwidth to measure the ionic current events as a single molecule translocates through a nanopore and combine a multi-functional optical system to implement the acquisition of the fluorescence, scattering spectrum, and photocurrent intensity of single molecule events in a nanopore confined space. Our system is a unified and unique platform for the protein nanopore, the solid-state nanopore, and the glass capillary nanopore, which has advantages in the comprehensive research of nanopore single-molecule techniques.


Subject(s)
Nanopores , Optical Devices , Electricity , Nanotechnology
19.
Analyst ; 146(1): 146-155, 2021 Jan 04.
Article in English | MEDLINE | ID: mdl-33107868

ABSTRACT

Herein, a label-free photoelectrochemical immunosensor based on a g-C3N4/CdSe nanocomposite was established and applied to detect carcinoembryonic antigen (CEA). The prepared nanocomposite materials were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), ultraviolet-visible absorption spectroscopy (UV-vis), X-ray photoelectron spectroscopy (XPS), fourier transform infrared spectrometer (FT-IR) and photoluminescence spectroscopy (PL). The results indicate that g-C3N4/CdSe nanocomposite materials were successfully synthesized. In a typical assembly process, the immunosensor was constructed by modifying a fluorine-doped tin oxide (FTO) electrode with poly dimethyl diallyl ammonium chloride (PDDA), the g-C3N4/CdSe nanocomposite, the anti-carcinoembryonic antigen antibody (Ab) and the blocking agent bovine serum albumin (BSA) successively. In the presence of CEA, the photocurrent signal of the prepared immunosensor decreased significantly. Accordingly, under the optimal conditions, a label-free photoelectrochemical immunosensor was established, and it exhibited excellent selectivity and repeatability for CEA detection. The detection limit was 0.21 ng mL-1, and the range was 10 ng mL-1-100 µg mL-1. Simultaneously, the immunosensor also provides a likely sensing device for detecting other protein targets, which is of great significance for early clinical diagnosis.


Subject(s)
Biosensing Techniques , Cadmium Compounds , Nanocomposites , Selenium Compounds , Carcinoembryonic Antigen , Electrochemical Techniques , Immunoassay , Spectroscopy, Fourier Transform Infrared
20.
Mol Pain ; 16: 1744806920963809, 2020.
Article in English | MEDLINE | ID: mdl-33054604

ABSTRACT

Schwann cells are components of the peripheral nerve myelin sheath, which supports and nourishes axons. Upon injury of the trigeminal nerve, Schwann cells are activated and cause trigeminal neuralgia by engulfing the myelin sheath and secreting various neurotrophic factors. Further, Schwann cells can repair the damaged nerve and thus alleviate trigeminal neuralgia. Here, we briefly describe the development and activation of Schwann cells after nerve injury. Moreover, we expound on the occurrence, regulation, and treatment of trigeminal neuralgia; further, we point out the current research deficiencies and future research directions.


Subject(s)
Schwann Cells/pathology , Trigeminal Neuralgia/pathology , Animals , Humans , Trigeminal Neuralgia/therapy
SELECTION OF CITATIONS
SEARCH DETAIL
...