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After cessation of blood flow or similar ischaemic exposures, deleterious molecular cascades commence in mammalian cells, eventually leading to their death1,2. Yet with targeted interventions, these processes can be mitigated or reversed, even minutes or hours post mortem, as also reported in the isolated porcine brain using BrainEx technology3. To date, translating single-organ interventions to intact, whole-body applications remains hampered by circulatory and multisystem physiological challenges. Here we describe OrganEx, an adaptation of the BrainEx extracorporeal pulsatile-perfusion system and cytoprotective perfusate for porcine whole-body settings. After 1 h of warm ischaemia, OrganEx application preserved tissue integrity, decreased cell death and restored selected molecular and cellular processes across multiple vital organs. Commensurately, single-nucleus transcriptomic analysis revealed organ- and cell-type-specific gene expression patterns that are reflective of specific molecular and cellular repair processes. Our analysis comprises a comprehensive resource of cell-type-specific changes during defined ischaemic intervals and perfusion interventions spanning multiple organs, and it reveals an underappreciated potential for cellular recovery after prolonged whole-body warm ischaemia in a large mammal.
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Sobrevivência Celular , Citoproteção , Perfusão , Suínos , Isquemia Quente , Animais , Morte Celular , Perfilação da Expressão Gênica , Isquemia/metabolismo , Isquemia/patologia , Isquemia/prevenção & controle , Especificidade de Órgãos , Perfusão/métodos , Suínos/anatomia & histologiaRESUMO
Given that exosomes released from cancer cells carry various tumor-specific proteins on their surface, they have emerged as a source of biomarkers for cancer diagnosis. However, developing accurate and reliable assays to detect exosomes in the early stages of disease with low abundance and complex systems remains challenging. Here, the prepared PDIG film has the ability to sense multiple signals from a single stimulus, in which the presence of cobalt(II) chloride and deep eutectic solvents (DES) endows PDIG with thermochromic and thermosensitive properties. Concretely, the PDIG served as the recognition interface in series with a bipolar electrode (BPE) that exhibits a highly sensitive color and conductivity response to temperature stimuli triggered by the light-harvesting probe TiO2@CNOs introduced via proximity hybridization assay triggering a rolling circle amplification strategy, resulting in the output of colorimetric, photoacoustic, and electrochemiluminescent signals for the detection of colorectal cancer exosomes. This work is expected to provide a new direction for exploring the multisignal amplification strategy of BPE, broaden the application of BPE in biological analysis, and provide new insights for developing highly information-sensing elements to ensure the multimodal coupling for cancer-specific exosome detection.
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Exossomos , Bioensaio , Cloretos , Cobalto , Colorimetria , Proteínas de NeoplasiasRESUMO
A stable and reusable electrochemiluminescent (ECL) signal amplification strategy was proposed through a pyrene-based conjugated polymer (Py-CP) triggered self-circulating enhancement system. Specifically, the delocalized conjugated π-electrons of Py-CPs made it an excellent coreactant to arouse the initial ECL signal improvement of Ru(phen)32+, but the subsequent signal reduction was attributed to the consumption of Py-CPs, in which this stage was called the signal sensitization evoking phase (SSEP). Then, the maximum use of ECL luminescence of Ru(phen)32+ produced in the SSEP was made to irradiate the photosensitizer Py-CPs for in situ producing numerous ·OH, and a stronger and more stable ECL response stage defined as the signal sensitization stabilize phase was reached. Encouragingly, the incorporation of Nb2C MXene quantum dots with an exceptional physicochemical property not only foreshortens the SSEP for quickly acquiring a stable ECL signal but also introduces the photoacoustic (PA) transduce mechanism for achieving dual-signal outputting. Ultimately, the portable and miniaturized ECL-PA synergetic sensing platform based on the closed-bipolar electrode realized sensitive let-7a detection in a wide linear range from 10-9 to 10-2 nM with a low detection limit of 3.3 × 10-10 nM and also demonstrated good selectivity, excellent stability, and high reliability. The successful application of an innovative signal transduction mechanism and dexterous coupling modality will provide new insights for advancing the development of flexible analytical devices.
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Técnicas Biossensoriais , Neoplasias Pulmonares , Humanos , Polímeros/química , Reprodutibilidade dos Testes , Medições Luminescentes , Técnicas Eletroquímicas , Pirenos , Neoplasias Pulmonares/diagnósticoRESUMO
A fluorescence quenching enhanced immunoassay has been developed to achieve ultrasensitive recognition of human epididymal 4 (HE4) modifying the fluorescence quencher. The carboxymethyl cellulose sodium-functionalized Nb2C MXene nanocomposite (CMC@MXene) was firstly introduced to quench the fluorescence signal of the luminophore Tb-Norfloxacin coordination polymer nanoparticles (Tb-NFX CPNPs). The Nb2C MXene nanocomposite as fluorescent nanoquencher inhibits the electron transfer between Tb and NFX to quench the fluorescent signal by coordinating the strongly electronegative carboxyl group on CMC with Tb (III) of Tb-NFX complex. Simultaneously, due to the superior photothermal conversion capability of CMC@MXene, the fluorescence signal has been further weakened by the photothermal effect driven non-radiative decay of the excited state under near-infrared laser irradiation. The constructed fluorescent biosensor based on CMC@MXene probe finally realized the enhanced fluorescence quenching effect, and achieved ultra-high sensitivity and selective detection of HE4, exhibiting a wide linear relationship with HE4 concentration on the logarithmic axis in the range of 10-5 to 10 ng/mL and a low detection limit of 3.3 fg/mL (S/N = 3). This work not only provides an enhanced fluorescent signal quenching method for the detection of HE4, but also provides novel insights for the design of fluorescent sensor toward different biomolecules.
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Carboximetilcelulose Sódica , Norfloxacino , Humanos , Fluorescência , Corantes , Raios InfravermelhosRESUMO
Based on the highly specific interaction between concanavalin A (Con A) and glucose (Glu), a competitive electrochemiluminescence (ECL) biosensor was constructed for ultrasensitive detection of Con A. Nanocomposites with excellent electrocatalytic and photothermal properties were obtained by covalently bonding zinc oxide quantum dots (ZnO QDs) to vanadium carbide MXene (V2C MXene) surfaces. The modification of ZnO QDs hinders the aggregation of V2C MXene and increases the catalytic activity of oxygen reduction reaction, thus amplifying the luminol cathodic emission. In addition, the excellent photothermal performance of the V2C MXene-ZnO QDs can convert light energy into heat energy under the irradiation of 808 nm near infrared laser, thus increasing the temperature of the reaction system and accelerating the electron transfer process to realize the synergistic amplified homogeneous ECL system. This innovative work not only enriches the fundamental research on multifunctional MXene nanomaterials for biosensing, but also provides an effective strategy for ECL signal amplification.
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Técnicas Biossensoriais , Concanavalina A , Eletroquímica , Eletroquímica/métodos , Transdução de Sinais , Concanavalina A/análise , Nitritos/química , Elementos de Transição/química , Pontos Quânticos , Óxido de Zinco/química , Humanos , Soro/químicaRESUMO
An electrochemiluminescent (ECL)-photoacoustic (PA) dual-signal output biosensor based on the modular optimization and wireless nature of a bipolar electrode (BPE) was constructed. To further simplify the detection process, the BPE structure was designed as three separate units: anode ECL collection, cathode catalytic amplification, and intermediate functional sensing units. Specifically, the anode unit was placed with Eosin Yellow, a cheap and effective ECL reagent, and the cathode unit was a laser-induced polyoxometalate-graphene electrode, which was helpful to enhance the anode ECL signal. The intermediate functional sensing unit consisted of a temperature-sensitive conductive film. Further, using a carbon nano-onion nanocomposite with excellent absorption performance in the near-infrared region as a signal tag not only leads to changes in the electrical conductivity of the film through heat transfer and thus affects the ECL signal but also produces a strong PA response. With this design, PA and ECL signals can be output simultaneously. This work not only realizes multiple modularization processes in the design of sensors but also implements the diversification of signal output modes, which will enrich the joint research field of ECL detection technology and other new detection methods.
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Técnicas Biossensoriais , Grafite , Neoplasias Ovarianas , Ânions , Técnicas Biossensoriais/métodos , Carbono , Técnicas Eletroquímicas/métodos , Eletrodos , Amarelo de Eosina-(YS) , Feminino , Grafite/química , Humanos , Medições Luminescentes/métodos , Cebolas , Neoplasias Ovarianas/diagnóstico , PolieletrólitosRESUMO
Microglia are essential for maintenance of normal brain function, with dysregulation contributing to numerous neurological diseases. Protocols have been developed to derive microglia-like cells from human induced pluripotent stem cells (hiPSCs). However, primary microglia display major differences in morphology and gene expression when grown in culture, including down-regulation of signature microglial genes. Thus, in vitro differentiated microglia may not accurately represent resting primary microglia. To address this issue, we transplanted microglial precursors derived in vitro from hiPSCs into neonatal mouse brains and found that the cells acquired characteristic microglial morphology and gene expression signatures that closely resembled primary human microglia. Single-cell RNA-sequencing analysis of transplanted microglia showed similar cellular heterogeneity as primary human cells. Thus, hiPSCs-derived microglia transplanted into the neonatal mouse brain assume a phenotype and gene expression signature resembling that of resting microglia residing in the human brain, making chimeras a superior tool to study microglia in human disease.
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Encéfalo/fisiologia , Células-Tronco Pluripotentes Induzidas/transplante , Microglia/transplante , Animais , Encéfalo/metabolismo , Encéfalo/cirurgia , Expressão Gênica , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Camundongos , Microglia/metabolismo , FenótipoRESUMO
A dual-readout immunosensor coupled with electrochemical impedance and temperature signal was successfully proposed to detect autoimmune hepatitis markers (ASGPR). Nb2C MXene with excellent conductivity, abundant surface functional groups, and extraordinary photothermal conversion efficiency, was designed to be a multifunctional biological probe, whose specific binding with antigen enhanced steric hindrance to generate electrochemical impedance signal, and at the same time, it had a strong optical response in the near-infrared band to achieve temperature output. In addition, poly(N-isopropyl acrylamide) (PNIPAM) was a temperature-sensitive polymer, which was adopted as the sensing matrix. When the multifunctional probe was specifically bound to the antigen, under 808-nm laser irradiation, the captured Nb2C MXene achieved photothermal conversion to increase the electrode surface temperature, and the conformation of PNIPAM changed from a free spiral to a spherical shape, further realizing double amplification of the EIS signal. Under the optimized experimental conditions, the impedance values and the temperature changes increased proportionally with the increase of the ASGPR concentration from 10-5 to 1 ng/mL, and the detection limit of the immunosensor was 3.3 × 10-6 ng/mL. The established dual-readout immunosensor exhibited good selectivity and acceptable stability and provided an effective detection method for autoimmune hepatitis marker detection.
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Técnicas Biossensoriais , Hepatite Autoimune , Técnicas Biossensoriais/métodos , Eletrodos , Hepatite Autoimune/diagnóstico , Humanos , Imunoensaio/métodos , Polímeros/químicaRESUMO
Theanine, a unique non-proteinogenic amino acid, is an important component of tea, as it confers the umami taste and relaxation effect of tea as a beverage. Theanine is primarily synthesized in tea roots and is subsequently transported to young shoots, which are harvested for tea production. Currently, the mechanism for theanine transport in the tea plant remains unknown. Here, by screening a yeast mutant library, followed by functional analyses, we identified the glutamine permease, GNP1 as a specific transporter for theanine in yeast. Although there is no GNP1 homolog in the tea plant, we assessed the theanine transport ability of nine tea plant amino acid permease (AAP) family members, with six exhibiting transport activity. We further determined that CsAAP1, CsAAP2, CsAAP4, CsAAP5, CsAAP6, and CsAAP8 exhibited moderate theanine affinities and transport was H+ -dependent. The tissue-specific expression of these six CsAAPs in leaves, vascular tissues, and the root suggested their broad roles in theanine loading and unloading from the vascular system, and in targeting to sink tissues. Furthermore, expression of these CsAAPs was shown to be seasonally regulated, coincident with theanine transport within the tea plant. Finally, CsAAP1 expression in the root was highly correlated with root-to-bud transport of theanine, in seven tea plant cultivars. Taken together, these findings support the hypothesis that members of the CsAAP family transport theanine and participate in its root-to-shoot delivery in the tea plant.
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Camellia sinensis/metabolismo , Sistemas de Transporte de Aminoácidos/metabolismo , Glutamatos/metabolismo , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismoRESUMO
The registration system of medical device Master Files is established to solve the problem that the outsourcing suppliers are not willing to cooperate with the device applicants in the process of providing medical device application documents. After a brief introduction of Master Files systems established by foreign regulatory agencies, this article focuses on the research of establishing a medical device Master Files registration system in China. The results show that the establishment of Chinese Master Files registration system can both improve the standardization and convenience of outsourcing activities of medical devices, and satisfy the needs of the development of medical device industry and regulatory system. At the same time, the probability of additional risk caused by the implementation of the system is low. Therefore, it is expected that the benefits of the system to promote public health outweigh the potential risks, which demonstrates that establishment of the system has important application values.
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Indústrias , China , Padrões de ReferênciaRESUMO
A self-enhanced electrochemiluminescent ratiometric immunoassay for zearalenone is described. A system composed of N-aminobutyl-N-ethylisoluminol (ABEI) and glutathione (GSH) produces a strong electrochemiluminescence (ECL) at an applied potential of 0.8 V, probably because of short electron transfer distance and reduced energy loss. The method also uses octahedral anatase mesocrystals (OAM) with a large specific surface facilitating immobilization of ABEI and GSH. Helical carbon nanotubes, possessing a large specific surface, superior mechanical stability, and excellent electrical conductivity which serve as a solid support, greatly enhanced the loading capacity for g-C3N4 nanosheets and horseradish peroxidase-labeled anti-antibody. The peroxidase accelerates the decomposition of H2O2 to produce reactive oxygen species (ROSs), amplifying the blue ECL of ABEI and the green ECL of g-C3N4. The ratiometric sandwich immunoassay (performed by the ratio of ECL intensity at - 1.3 V and 0.8 V) allows for sensitive and reliable determination of ZEN in a wide linear range from 1.0 × 10-4 ng/mL to 10 ng/mL. The method was successfully applied to the analysis of corn hazelnut samples for ZEN. Graphical abstract Schematic presentation of a self-enhanced electrochemiluminescent ratiometric immunosensor based on octahedral anatase mesocrystals (OAM) supported ABEI-glutathione (GSH) and g-C3N4 functionalized helical carbon nanotubes (HCNT) for zearalenone (ZEN) determination.
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An impedimetric immunoassay was designed for ultrasensitive determination of zearalenone (ZEN). It is making use of the peroxidase-like activity of strip-shaped Co3O4 (ssCo3O4) which catalyzes the oxidation of 4-chloro-1-naphthol to produce an insoluble precipitate in the presence of H2O2. The precipitate is electrically nonconductive and accumulates on the electrode, thereby retarding the electron transfer from the redox probe ferro/ferricyanide to the surface of electrode. This amplifies the impedimetric signal in accordance with logarithm of the concentration of ZEN. The electrode was further modified with TiO2 mesocrystals (TiO2 MCs) which improve the capture of more analytes and increase the performance of the immunoassay. Under optimized experimental condition, the impedimetric signal increased linearly with the logarithm of the ZEN concentration range between 0.1 fg·mL-1 to 10 pg·mL-1. The detection limit is of 33 ag· mL-1. Graphical abstractThis work describes an impedimetric immunoassay based on the use of strip-shaped Co3O4 that catalyzes the production of an insoluble precipitate in the presence of H2O2 on the surface of a glassy carbon electrode. The effect was used for signal amplification in an electrochemical immunoassay for zearalenone.
Assuntos
Cobalto/química , Imunoensaio , Óxidos/química , Peroxidase/química , Fitas Reagentes/química , Zearalenona/análise , Cobalto/metabolismo , Eletrodos , Humanos , Oxirredução , Óxidos/metabolismo , Tamanho da Partícula , Peroxidase/metabolismo , Fitas Reagentes/metabolismo , Propriedades de Superfície , Zearalenona/metabolismoRESUMO
An ultrasensitive competitive-type electrochemiluminescence immunoassay for the mycotoxin zearalenone is described. The method is based on the use of (a) a mimotope peptide that was selected from a phage displayed peptide library and used to substitute ZEN for designing the competitive assay; (b) NiFe2O4 nanotubes with large specific surface area loaded with the ECL probe Ru(bpy)32+; and (c) poly(vinylpyrrolidone) (PVP)-assisted synthesis of TiO2 mesocrystals that acts as the sensing platform and support for antibody immobilization. Under the optimized conditions and at an ECL working potential of 1.1 V, a linear response is found for ZEN in the 0.1 to 1.0 × 10-5 ng·mL-1 concentration range with a detection limit as low as 3.3 fg·mL-1. Graphical abstract An ultrasensitive competitive-type electrochemiluminescence (ECL) immunosensor based on mimotope peptide was constructed for the detection of Zearalenone.
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In response to phosphate (Pi) deficiency, it has been shown that micro-RNAs (miRNAs) and mRNAs are transported through the phloem for delivery to sink tissues. Growing evidence also indicates that long non-coding RNAs (lncRNAs) are critical regulators of Pi homeostasis in plants. However, whether lncRNAs are present in and move through the phloem, in response to Pi deficiency, remains to be established. Here, using cucumber as a model plant, we show that lncRNAs are enriched in the phloem translocation stream and respond, systemically, to an imposed Pi-stress. A well-known lncRNA, IPS1, the target mimic (TM) of miRNA399, accumulates to a high level in the phloem, but is not responsive to early Pi deficiency. An additional 24 miRNA TMs were also detected in the phloem translocation stream; among them miRNA171 TMs and miR166 TMs were induced in response to an imposed Pi stress. Grafting studies identified 22 lncRNAs which move systemically into developing leaves and root tips. A CU-rich PTB motif was further identified in these mobile lncRNAs. Our findings revealed that lncRNAs respond to Pi deficiency, non-cell-autonomously, and may act as systemic signaling agents to coordinate early Pi deficiency signaling, at the whole-plant level.
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Floema/metabolismo , Fosfatos/deficiência , Transporte de RNA , RNA Longo não Codificante/genética , RNA de Plantas/genética , Sequência de Bases , Cucumis sativus/genética , Regulação da Expressão Gênica de Plantas , Motivos de Nucleotídeos/genética , Especificidade de Órgãos/genética , Proteínas de Plantas/metabolismo , RNA Longo não Codificante/metabolismo , RNA de Plantas/metabolismo , Regulação para Cima/genéticaRESUMO
Post-translational modification (PTM) of nuclear receptor superfamily members regulates various aspects of their biology to include sub-cellular localization, the repertoire of protein-binding partners, as well as their stability and mode of degradation. The nuclear receptor pregnane X receptor (PXR, NR1I2) is a master-regulator of the drug-inducible gene expression in liver and intestine. The PXR-mediated gene activation program is primarily recognized to increase drug metabolism, drug transport, and drug efflux pathways in these tissues. The activation of PXR also has important implications in significant human diseases including inflammatory bowel disease and cancer. Our recent investigations reveal that PXR is modified by multiple PTMs to include phosphorylation, SUMOylation, and ubiquitination. Using both primary cultures of hepatocytes and cell-based assays, we show here that PXR is modified through acetylation on lysine residues. Further, we show that increased acetylation of PXR stimulates its increased SUMO-modification to support active transcriptional suppression. Pharmacologic inhibition of lysine de-acetylation using trichostatin A (TSA) alters the sub-cellular localization of PXR in cultured hepatocytes, and also has a profound impact upon PXR transactivation capacity. Both the acetylation and SUMOylation status of the PXR protein is affected by its ability to associate with the lysine de-acetylating enzyme histone de-acetylase (HDAC)3 in a complex with silencing mediator of retinoic acid and thyroid hormone receptor (SMRT). Taken together, our data support a model in which a SUMO-acetyl 'switch' occurs such that acetylation of PXR likely stimulates SUMO-modification of PXR to promote the active repression of PXR-target gene expression. This article is part of a Special Issue entitled: Xenobiotic nuclear receptors: New Tricks for An Old Dog, edited by Dr. Wen Xie.
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Hepatócitos/metabolismo , Histona Desacetilases/metabolismo , Lisina/metabolismo , Correpressor 2 de Receptor Nuclear/metabolismo , Processamento de Proteína Pós-Traducional , Receptores de Esteroides/química , Acetilação , Sequência de Aminoácidos , Animais , Linhagem Celular , Genes Reporter , Hepatócitos/citologia , Hepatócitos/efeitos dos fármacos , Histona Desacetilases/genética , Ácidos Hidroxâmicos/farmacologia , Luciferases/genética , Luciferases/metabolismo , Lisina/química , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Correpressor 2 de Receptor Nuclear/genética , Receptor de Pregnano X , Cultura Primária de Células , Receptores de Esteroides/genética , Receptores de Esteroides/metabolismo , Sumoilação , Ativação Transcricional/efeitos dos fármacos , UbiquitinaçãoRESUMO
In this work, we first exposed that the application of p-type semiconductor, silver iodide-chitosan nanoparticle (SICNP), acted as peroxidase mimetic to catalyze the bioprecipitation reaction for signal-amplification photocathodic immunosensing of human interleukin-6 (IL-6). After immobilization of captured antibody onto a polyethylenimine-functionalized carbon nitride (CN) matrix, SICNPs as photoactive tags and peroxidase mimetics were labeled on secondary antibodies, which were subsequently introduced onto the sensing interface to construct sandwich immunoassay platform through antigen-antibody specific recognition. Due to the matched energy levels between CN and AgI, the photocurrent intensity and photostability of SICNP were dramatically improved with rapid separation and transportation of photogenerated carriers. Moreover, the insoluble product in effective biocatalytic precipitation reaction served as electron acceptor to scavenge the photoexcited electron, leading to great amplification of the photocurrent signal of SICNP again. With the help of multiamplification processes, this photocathodic immunosensor presented a turn-on photoelectrochemical performance for IL-6, which showed wide linear dynamic range from 10(-6) to 10 pg/mL with the ultralow detection limit of 0.737 ag/mL. This work also performed the promising application of SICNP in developing an ultrasensitive, cost-effective, and enzyme-free photocathodic immunosensor for biomarkers.
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Anticorpos/imunologia , Biocatálise , Quitosana/química , Imunoensaio/métodos , Interleucina-6/imunologia , Iodetos/química , Nanopartículas/química , Processos Fotoquímicos , Compostos de Prata/química , Anticorpos Imobilizados/imunologia , Reações Antígeno-Anticorpo , Catálise , Eletrodos , Humanos , Imunoensaio/instrumentaçãoRESUMO
It is a great challenge to fabricate multiplex and convenient photoelectrochemical biosensors for ultrasensitive determination of biomarkers. Herein, a fascinating potentiometric addressable photoelectrochemical biosensor was reported for double biomarkers' detection by varying the applied bias in the detection process. In this biosensor, the nanocomposite of cube anatase TiO2 mesocrystals and polyamidoamine dendrimers modified a dual disk electrode as an excellent photoelectrochemical sensing matrix. Subsequently, two important biomarkers in serum for prostate cancer, prostate-specific antigen and human interleukin-6, were immobilized onto the different disks of modified electrode via glutaraldehyde bridges. Then another two photosensitizers, graphitic-carbon-nitride-labeled and CS-AgI-labeled different antibodies, were self-assembled onto the electrode surface by a corresponding competitive immune recognition reaction. The change in photocurrent with the target antigen concentration at different critical voltages enables us to selectively and quantitatively determine targets. The results demonstrated that this potentiometric addressable photoelectrochemical biosensing strategy not only has great promise as a new point-of-care diagnostic tool for early detection of prostate cancer but also can be conveniently expanded to multiplex biosensing by simply change biomarkers. More importantly, this work provides an unambiguous operating guideline of multiplex photoelectrochemical immunoassay.
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Biomarcadores/análise , Técnicas Biossensoriais/métodos , Interleucina-6/análise , Calicreínas/análise , Potenciometria/métodos , Antígeno Prostático Específico/análise , Dendrímeros/química , Eletrodos , Humanos , Limite de Detecção , Nanocompostos/química , Poliaminas/química , Titânio/químicaRESUMO
A visible light responsive photocatalytic hybrid with excellent photoelectrochemical activity was first fabricated via the self-assembly of Au nanorods onto poly(l-cysteine) modified graphitic carbon nitride nanosheets. Herein, layered structural graphitic carbon nitride nanosheets with a proper band gap, high stability, and nontoxicity, as a photoactive material, demonstrate a high photocatalytic activity. Furthermore, the incorporation of multifunctional Au nanorods gave the hybrid a Schottky barrier and localized surface plasmonic resonance, which considerably enhanced the separation of the photo-excited electrons and holes, resulting in increased photoelectrochemical performance. As a proof of concept, mercapto-beta-cyclodextrin as a bionic recognition device was introduced into the hybrid to selectively detect naringin on the basis of the dramatic decreasing of photocurrent. The visible-light driven photoelectrochemical sensor exhibited excellent analytical performance, including high sensitivity, good selectivity and wide linear range from 1 × 10(-4) to 1 × 10(-10) M.
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Herein, simple molecular recognition sites for formaldehyde were designed on electrospun polymer nanofibers. In order to improve the conductivity of the electrospun polymer nanofibers, carbon nanotubes were introduced into the resulting nanofibers. By employing these functionalized nanocomposite fibers to fabricate a biomimetic sensor platform, an obvious change caused by recognition between recognition sites and formaldehyde molecules was monitored through electrochemical impedance spectroscopy (EIS). The experimental conditions were optimized and then a quantitative method for formaldehyde sensing in low concentration was established. The relative results demonstrated that the sensor based on biomimetic recognition nanofibers displays an excellent recognition capacity toward formaldehyde. The linear response range of the sensor was between 1 × 10(-6) mol L(-1) and 1 × 10(-2) mol L(-1), with the detection limit of 8 × 10(-7) mol L(-1). The presented research provided a fast, feasible and sensitive method for formaldehyde with good anti-interference capabilities and good stability, which could meet the practical requirement for formaldehyde assay.
Assuntos
Materiais Biomiméticos/química , Técnicas Biossensoriais/métodos , Espectroscopia Dielétrica/métodos , Formaldeído/análise , Limite de Detecção , Nanocompostos/química , Nanofibras/química , Nanotubos de Carbono/químicaRESUMO
A ternary hybrid was developed through interaction between a hierarchical-ordered TiO2 and a thiol group that was obtained by in situ chemical polymerization of L-cysteine on the carbon nanohorn (CNH) superstructure modified electrode. Herein, unique-ordered TiO2 superstructures with quasi-octahedral shape that possess high crystallinity, high porosity, oriented subunit alignment, very large specific surface area, and superior photocatalytic activity were first introduced as a photosensitizer element in the photoelectrochemical determination. Additionally, the assembly of hierarchical-structured CNHs was used to provide an excellent electron-transport matrix to capture and transport an electron from excited anatase to the electrode rapidly, hampering the electron-hole recombination effectively, resulting in improved photoelectrochemical response and higher photocatalytic activity in the visible light region. Owing to the dependence of the photocurrent signal on the concentration of electron donor, 4-methylimidozal, which can act as a photogenerated hole scavenger, an exquisite photoelectrochemical sensor was successfully fabricated with a wide linear range from 1 × 10(-4) to 1 × 10(-10) M, and the detection limit was down to 30 pM. The low applied potential of 0.2 V was beneficial to the elimination of interference from other reductive species that coexisted in the real samples. More importantly, the mesocrystal was first introduced in the fabricating of a biosensor, which not only opens up a new avenue for biosensors manufactured based on mesocrystal materials but also provides beneficial lessons in the research fields ranging from solar cells to photocatalysis.