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Herein, we developed a bio-functionalized solution-immersed silicon (SIS) sensor at the single-cell level to identify Erwinia amylovora (E. amylovora), a highly infectious bacterial pathogen responsible for fire blight, which is notorious for its rapid spread and destructive impact on apple and pear orchards. This method allows for ultra-sensitive measurements without pre-amplification or labeling compared to conventional methods. To detect a single cell of E. amylovora, we used Lipopolysaccharide Transporter E (LptE), which is involved in the assembly of lipopolysaccharide (LPS) at the surface of the outer membrane of E. amylovora, as a capture agent. We confirmed that LptE interacts with E. amylovora via LPS through in-house ELISA analysis, then used it to construct the sensor chip by immobilizing the capture molecule on the sensor surface modified with 3'-Aminopropyl triethoxysilane (APTES) and glutaraldehyde (GA). The LptE-based SIS sensor exhibited the sensitive and specific detection of the target bacterial cell in real time. The dose-response curve shows a linearity (R2 > 0.992) with wide dynamic ranges from 1 to 107 cells/mL for the target bacterial pathogen. The sensor showed the value change (dΨ) of approximately 0.008° for growing overlayer thickness induced from a single-cell E. amylovora, while no change in the control bacterial cell (Bacillus subtilis) was observed, or negligible change, if any. Furthermore, the bacterial sensor demonstrated a potential for the continuous detection of E. amylovora through simple surface regeneration, enabling its reusability. Taken together, our system has the potential to be applied in fields where early symptoms are not observed and where single-cell or ultra-sensitive detection is required, such as plant bacterial pathogen detection, foodborne pathogen monitoring and analysis, and pathogenic microbial diagnosis.
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Erwinia amylovora , Lipopolissacarídeos , Bacillus subtilis , Ensaio de Imunoadsorção EnzimáticaRESUMO
We have developed a membrane filter-assisted cell-based biosensing platform by using a polyester membrane as a three-dimensional (3D) cell culture scaffold in which cells can be grown by physical attachment. The membrane was simply treated with ethanol to increase surficial hydrophobicity, inducing the stable settlement of cells via gravity. The 3D membrane scaffold was able to provide a relatively longer cell incubation time (up to 16 days) as compared to a common two-dimensional (2D) cell culture environment. For a practical application, we fabricated a cylindrical cartridge to support the scaffold membranes stacked inside the cartridge, enabling not only the maintenance of a certain volume of culture media but also the simple exchange of media in a flow-through manner. The cartridge-type cell-based analytical system was exemplified for pathogen detection by measuring the quantities of toll-like receptor 1 (TLR1) induced by applying a lysate of P. aeruginosa and live E. coli, respectively, providing a fast, convenient colorimetric TLR1 immunoassay. The color images of membranes were digitized to obtain the response signals. We expect the method to further be applied as an alternative tool to animal testing in various research areas such as cosmetic toxicity and drug efficiency.
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Técnicas Biossensoriais , Escherichia coli , Animais , Técnicas de Cultura de Células , ImunoensaioRESUMO
The purpose of this study is to assess the effect of autoclave sterilization on the cyclic fatigue and torsional fracture resistance of ProTaper Universal (PTU), K3XF, HyFlex EDM (EDM), and TF adaptive (TFA). Sixty instruments from each file type were divided into two categories for cyclic fatigue group (CGr) and torsional fracture group (TGr). CGr and TGr were divided into three subgroups, respectively, consisting of ten instruments from each file type. Cyclic fatigue fracture test was performed using artificial canal made of stainless steel, and the mean number of cycles to failure (NCF) were determined. CGr1, the files were tested to establish baseline for NCF; CGr2, the files were tested cyclic fatigue after 10 cycles of autoclave; CGr3, instruments were autoclaved after being cycled to 25, 50, and 75% of corresponding NCF determined in CGr1, followed by cyclic fatigue test. The torsional fracture test was performed without autoclave (TGr1), after 3-cycle autoclave (TGr2), and 7-cycle autoclave (TGr3), respectively, which evaluated maximum torque and angular deflection. NCF, maximum torque and angular deflection were compared using one-way ANOVA with Bonferroni test. Two-way ANOVA was performed to determine the interaction between 'autoclave treatment' and 'type of NiTi file'. EDM showed highest NCF within the same autoclave treatment. TFA presented the lowest maximum torque and the highest angular deflection, and PTU presented the lowest angular deflection. Within the same NiTi file systems, most of NCF, maximum torque and angular deflection of tested files were not significantly influenced by autoclave condition.
Assuntos
Instrumentos Odontológicos , Preparo de Canal Radicular , Ligas Dentárias , Desenho de Equipamento , Falha de Equipamento , Teste de Materiais , Esterilização , Estresse Mecânico , TitânioRESUMO
An electrochemical immunosensor employs antibodies as capture and detection means to produce electrical charges for the quantitative analysis of target molecules. This sensor type can be utilized as a miniaturized device for the detection of point-of-care testing (POCT). Achieving high-performance analysis regarding sensitivity has been one of the key issues with developing this type of biosensor system. Many modern nanotechnology efforts allowed for the development of innovative electrochemical biosensors with high sensitivity by employing various nanomaterials that facilitate the electron transfer and carrying capacity of signal tracers in combination with surface modification and bioconjugation techniques. In this review, we introduce novel nanomaterials (e.g., carbon nanotube, graphene, indium tin oxide, nanowire and metallic nanoparticles) in order to construct a high-performance electrode. Also, we describe how to increase the number of signal tracers by employing nanomaterials as carriers and making the polymeric enzyme complex associated with redox cycling for signal amplification. The pros and cons of each method are considered throughout this review. We expect that these reviewed strategies for signal enhancement will be applied to the next versions of lateral-flow paper chromatography and microfluidic immunosensor, which are considered the most practical POCT biosensor platforms.
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Técnicas Eletroquímicas , Técnicas Biossensoriais , Ouro , Imunoensaio , Nanopartículas MetálicasRESUMO
Herein, we present a facile and simple strategy for in situ synthesis of functionalized carbon nanoparticles (CNPs) via direct pyrolysis of ethylenediaminetetraacetic acid (EDTA) on silicon surface. The CNPs were incorporated in hybrid planar n-Si and poly(3,4-etyhlenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) solar cells to improve device performance. We demonstrate that the CNPs-incorporated devices showed increased electrical conductivity (reduced series resistance) and minority carrier lifetime (better charge carrier collection) than those of the cells without CNPs due to the existence of electrically conductive sp 2-hybridized carbon at the heterojunction interfaces. With an optimal concentration of CNPs, the hybrid solar cells exhibited power conversion efficiency up to 11.95%, with an open-circuit voltage of 614 mV, short-circuit current density of 26.34 mA cm-2, and fill factor of 73.93%. These results indicate that our approach is promising for the development of highly efficient organic-inorganic hybrid solar cells.
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Antibodies with rapid reaction kinetics (high association and dissociation rates), named reversible antibodies, are used to perform continuous monitoring of sensitive disease biomarkers. In cases of acute myocardial infarction (AMI), continuous monitoring and early diagnosis are important. Human myoglobin (Myo) is a useful biomarker for AMI during the early stage after the onset of symptoms. In this study, a single-chain variable fragment (scFv) specific to Myo was derived from an IgG antibody that has rapid reaction kinetics. Enzyme-linked immunosorbent assay revealed that recombinant scFv exhibited 3.8-fold reduced affinity compared with the parent IgG antibody based on the antibody concentration necessary for 50% of the maximum signal. The scFv retained the rapid reaction kinetic mode with average kon and koff of 2.63 × 10(5) M(-1) Sec(-1) and 3.25 × 10(-3) Sec(-1) , respectively, which were reduced to 10- and 2.3-fold compared with those of the parent antibody. The equilibrium constant for the association of the scFv (KA = 8.09 × 10(7) M(-1) ) was 4.6-fold lower than that of its parent IgG antibody. This scFv may be a starting point for further mutagenesis/kinetic and structural analyses providing valuable insight into the mechanism of reversible antibodies.
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Mutagênese , Mioglobina/imunologia , Anticorpos de Cadeia Única/genética , Anticorpos de Cadeia Única/imunologia , Sequência de Aminoácidos , Clonagem Molecular , Ensaio de Imunoadsorção Enzimática , Humanos , Cinética , Dados de Sequência Molecular , Anticorpos de Cadeia Única/químicaRESUMO
Myoglobin is an early biomarker for acute myocardial infarction. Recently, we isolated the antibody IgG-Myo2-7ds, which exhibits unique rapid reaction kinetics toward human myoglobin antigen. Antibodies with rapid dissociation kinetics are thought to be premature IgG forms that are produced during the early stage of in vivo immunization. In the present study, we identified the epitope region of the IgG-Myo2-7ds antibody to be the C-terminal region of myoglobin, which corresponds to 144-154 aa. The Fab fragment was directly purified by papain cleavage and protein G affinity chromatography and demonstrated kinetics of an association constant of 4.02 × 10(4) M(-1) s(-1) and a dissociation constant of 2.28 × 10(-2) s(-1), which retained the unique reaction kinetics of intact IgG-Myo2-7ds antibodies. Because a rapid dissociation antibody can be utilized for antibody recycling, the results from this study would provide a platform for the development of antibody engineering in potential diagnostic areas such as a continuous monitoring system for heart disease.
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Fragmentos Fab das Imunoglobulinas/isolamento & purificação , Fragmentos Fab das Imunoglobulinas/metabolismo , Mioglobina/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/imunologia , Cromatografia de Afinidade/métodos , Ensaio de Imunoadsorção Enzimática , Mapeamento de Epitopos , Epitopos/imunologia , Humanos , Fragmentos Fab das Imunoglobulinas/imunologia , Cinética , Camundongos , Dados de Sequência Molecular , Mioglobina/genética , Mioglobina/metabolismoRESUMO
A label-free immunosensing method based on the conformational change of calcium-binding protein (CBP) depending on analyte concentration was explored for semi-continuous analysis of free Ca(2+). Glucose-galactose-binding protein as a CBP and produced as a recombinant protein by Escherichia coli was used as the immunogen to produce monoclonal antibodies by hybridoma technology. We finally screened the 3-6F cell clone, which produced the desired antibody specific to a particular structural conformation of the protein that occurred only upon CBP-calcium complex formation. To construct an immunosensor, the antibody was immobilized via a secondary antibody on an Octet Red optical fiber-based label-free sensor. Calcium analysis was conducted on the sensor in combination with CBP previously added to the aqueous sample, which distinguished the sensor signal according to the analyte concentration. The immunosensor produced a signal in real time with a response time of approximately 15 min and could be reused for analyses of different samples in a semi-continuous manner. The minimum detection limit of the analyte under optimal conditions was 0.09 mM and the upper limit was about 5 mM (log-logit transformed standard curve linearity: R(2) > 98%). In sample tests with milk, the analytical performance of the sensor was highly correlated (R(2) > 99%) with that of the reference system based on the KMnO4 titration method (ISO 12081). Although the sensor showed cross-reactivity at high concentrations (>1 mM) of cations including zinc, iron, manganese, and copper, these ionic components were not traceable (<0.01 mM) in milk.
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Proteínas de Ligação ao Cálcio/metabolismo , Cálcio/análise , Tecnologia de Fibra Óptica/métodos , Imunoensaio/métodos , Leite/química , Proteínas de Transporte de Monossacarídeos/metabolismo , Proteínas Periplásmicas de Ligação/metabolismo , Animais , Anticorpos Imobilizados/imunologia , Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/química , Proteínas de Ligação ao Cálcio/imunologia , Camundongos , Proteínas de Transporte de Monossacarídeos/química , Proteínas de Transporte de Monossacarídeos/imunologia , Fibras Ópticas , Proteínas Periplásmicas de Ligação/química , Proteínas Periplásmicas de Ligação/imunologia , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismoRESUMO
Myoglobin is one of the early biomarkers for acute myocardial infarction. Recently, we have screened an antibody with unique rapid reaction kinetics toward human myoglobin antigen. Antibodies with rapid reaction kinetics are thought to be an early IgG form produced during early stage of in vivo immunization. We produced a recombinant scFv fragment for the premature antibody from Escherichia coli using refolding technology. The scFv gene was constructed by connection of the V(H)-V(L) sequence with a (Gly4Ser)3 linker. The scFv fragment without the pelB leader sequence was expressed at a high level, but the solubility was extremely low. A high concentration of 8 M urea was used for denaturation. The dilution refolding process in the presence of arginine and the redox reagents GSH and GSSH successfully produced a soluble scFv protein. The resultant refolded scFv protein showed association and dissociation values of 9.32 × 10â»4 M⻹·s⻹ and 6.29 × 10⻳ s⻹, respectively, with an affinity value exceeding 107 M⻹ (k(on)/k(off)), maintaining the original rapid reaction kinetics of the premature antibody. The refolded scFv could provide a platform for protein engineering for the clinical application for diagnosis of heart disease and the development of a continuous biosensor.
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Mioglobina/imunologia , Redobramento de Proteína , Anticorpos de Cadeia Única/química , Humanos , CinéticaRESUMO
Zinc-air battery (ZAB) technology is considered one of the promising candidates to complement the existing lithium-ion batteries for future large-scale high-energy-storage demands. The scientific literature reveals many efforts for the ZAB chemistries, materials design, and limited accounts for cell design principles with apparently superior performances for liquid and solid-state electrolytes. However, along with the difficulty of forming robust solid-electrolyte interphases, the discrepancy in testing methods and assessment metrics severely challenges the realistic evaluation/comparison and commercialization of ZABs. Here, strategies to formulate reversible zinc anodes are proposed and specific cell-level energy metrics (100-500 Wh kg-1 ) and realistic long-cycling operations are realized. Stabilizing anode/electrolyte interfaces results in a cumulative capacity of 25 Ah cm-2 and Coulomb efficiency of >99.9% for 5000 plating/stripping cycles. Using 1-10 Ah scale (≈500 Wh kg-1 at cell level) solid-state zinc-air pouch cells, scale-up insights for Ah-level ZABs that can progress from lab-scale research to practical production are also offered.
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To ensure the operational stability of transistor-based biosensors in aqueous electrolytes during multiple measurements, effective electrode passivation is crucially important for reliable and reproducible device performances. This paper presents a highly effective and efficient electrode passivation method using a facile solution-processed self-assembled multilayer (SAML) with excellent insulation property to achieve operational stability and reproducibility of electrolyte-gated transistor (EGT) biosensors. The SAML is created by the consecutive self-assembly of three different molecular layers of 1,10-decanedithiol, vinyl-polyhedral oligomeric silsesquioxane, and 1-octadecanethiol. This passivation enables EGT to operate stably in phosphate-buffered saline (PBS) during repeated measurements over multiple cycles without short-circuiting. The SAML-passivated EGT biosensor is fabricated with a solution-processed In2O3 thin film as an amorphous oxide semiconductor working both as a semiconducting channel in the transistor and as a functionalizable biological interface for a bioreceptor. The SAML-passivated EGT including In2O3 thin film is demonstrated for the detection of Tau protein as a biomarker of Alzheimer's disease while employing a Tau-specific DNA aptamer as a bioreceptor and a PBS solution with a low ionic strength to diminish the charge-screening (Debye length) effect. The SAML-passivated EGT biosensor functionalized with the Tau-specific DNA aptamer exhibits ultrasensitive, quantitative, and reliable detection of Tau protein from 1 × 10-15 to 1 × 10-10 M, covering a much larger range than clinical needs, via changes in different transistor parameters. Therefore, the SAML-based passivation method can be effectively and efficiently utilized for operationally stable and reproducible transistor-based biosensors. Furthermore, this presented strategy can be extensively adapted for advanced biomedical devices and bioelectronics in aqueous or physiological environments.
Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Proteínas tau , Transistores Eletrônicos , Reprodutibilidade dos Testes , Técnicas Biossensoriais/métodos , Eletrodos , Eletrólitos , ÁguaRESUMO
The rational design of wide-temperature operating Zn-air batteries is crucial for their practical applications. However, the fundamental challenges remain; the limitation of the sluggish oxygen redox kinetics, insufficient active sites, and poor efficiency/cycle lifespan. Here we present heterointerface-promoted sulfur-deficient cobalt-tin-sulfur (CoS1-δ/SnS2-δ) trifunctional electrocatalysts by a facile solvothermal solution-phase approach. The CoS1-δ/SnS2-δ displays superb trifunctional activities, precisely a record-level oxygen bifunctional activity of 0.57 V (E1/2 = 0.90 V and Ej=10 = 1.47 V) and a hydrogen evolution overpotential (41 mV), outperforming those of Pt/C and RuO2. Theoretical calculations reveal the modulation of the electronic structures and d-band centers that endorse fast electron/proton transport for the hetero-interface and avoid the strong adsorption of intermediate species. The alkaline Zn-air batteries with CoS1-δ/SnS2-δ manifest record-high power density of 249 mW cm-2 and long-cycle life for >1000 cycles under harsh operations of 20 mA cm-2, surpassing those of Pt/C + RuO2 and previous state-of-the-art catalysts. Furthermore, the solid-state flexible Zn-air battery also displays remarkable performance with an energy density of 1077 Wh kg-1, >690 cycles for 50 mA cm-2, and a wide operating temperature from +80 to -40 °C with 85% capacity retention, which provides insights for practical Zn-air batteries.
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In this study, a novel mammalian cell receptor-based immuno-analytical method was developed for the detection of food-poisoning microorganisms by employing toll-like receptors (TLRs) as sensing elements. Upon infection with bacterium, the host cells respond by expressing TLRs, particularly TLR1, TLR2, and TLR4, on the outer membrane surfaces. To demonstrate the potential of using this method for detection of foodborne bacteria, we initially selected two model sensing systems, expression of TLR1 on a cell line, A549, for Escherichia coli and TLR2 on a cell line, RAW264.7, for Shigella sonnei (S. sonnei). Each TLR was detected using antibodies specific to the respective marker. We also found that the addition of immunoassay for the pathogen captured by the TLRs on the mammalian cells significantly enhanced the detection capability. A dual-analytical system for S. sonnei was constructed and successfully detected an extremely low number (about 3.2 CFU per well) of the pathogenic bacterium 5.1 h after infection. This detection time was 2.5 h earlier than the time required for detection using the conventional immunoassay. To endow the specificity of detection, the target bacterium was immuno-magnetically concentrated by a factor of 50 prior to infection. This further shortened the response to approximately 3.4 h, which was less than half of the time needed when the conventional method was used. Such enhanced performance could basically result from synergistic effects of bacterial dose increase and subsequent autocrine signaling on TLRs' up-regulation upon infection with live bacterium. This TLR-based immuno-sensing approach may also be expanded to monitor infection of the body, provided scanning of the signal is feasible.
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Técnicas Biossensoriais/métodos , Escherichia coli/isolamento & purificação , Imunoensaio/métodos , Shigella sonnei/isolamento & purificação , Receptores Toll-Like/metabolismo , Animais , Linhagem Celular , Escherichia coli/imunologia , Escherichia coli/fisiologia , Regulação da Expressão Gênica/imunologia , Humanos , Imunidade Inata , Imãs/química , Shigella sonnei/imunologia , Shigella sonnei/fisiologiaRESUMO
In this study, rapidly reversible antibodies were produced and the binding kinetics, stability, and utility as an analytical binder were evaluated. The number of times the animals were immunized with the antigen (myoglobin as marker for acute myocardial infarction [AMI]) was limited to two, increasing the chances of producing premature antibodies that rapidly reacted with the binding partner in both association and dissociation. The rate constants were higher than 1×10(6)M(-1)s(-1) and 1×10(-3)s(-1), respectively, and the affinity exceeded 10(8)M(-1). They responded to an abrupt environmental change (acidic pH in this study) where the reaction kinetics was changed to slow binding, particularly for dissociation, resulting in a 10-fold increase in affinity. The binding characteristic before and after the transition were stable at 37°C for longer than 1 month, suggesting that the rapidly reversible antibody was the intermediate of the slow binder. The rapid kinetic antibody was used as the primary binder in the conventional competitive immunoassay, which displayed a lower sensitivity than the transformed antibody due to its lower affinity. We further demonstrated that, on combination with a microfluidic label-free sensor, the reaction could be continuously monitored in serum medium by recycling the same antibody without employing the regeneration step.
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Anticorpos/metabolismo , Imunoensaio/métodos , Animais , Anticorpos/análise , Formação de Anticorpos , Técnicas Biossensoriais , Hibridomas/imunologia , Concentração de Íons de Hidrogênio , Camundongos , Camundongos Endogâmicos BALB C , Infarto do Miocárdio/diagnóstico , Infarto do Miocárdio/imunologia , Mioglobina/sangueRESUMO
Acute myocardial infarction is a typical disorder that requires continuous monitoring for early detection of potential life-threatening situations. To this end, we used different methods to screen for rapidly reversible antibodies, among 22 hybridoma clones, against cardiac troponin I (cTnI), which is a specific marker indicating the disease. The dissociation rates of antibodies were underestimated by up to a factor of 1000 because of bivalent binding when tested with the antigen immobilized on solid surfaces. This effect was also observed in a sandwich immunoassay, in which the detection antibody cross-linked with various antigen molecules already bound to the capture antibody. Although multiple binding events contributed to enhanced detection capability, it was difficult to recycle the immunosensor. We then devised a screening system by arranging the test antibody for the capture binder immobilized on a label-free sensor. This enabled us to select fast reactive antibodies of which one (clone 24) was shown to be recyclable, even in serum-containing medium. Using this antibody, repetitive detection of cTnI with a rapid response time (half-life of dissociation: about 4min on average) and high detection capability (0.1ng/ml) was achieved, which is very important for detection in a clinical setting.
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Anticorpos Monoclonais/imunologia , Imunoensaio , Miocárdio/metabolismo , Troponina I/sangue , Anticorpos Imobilizados/química , Anticorpos Imobilizados/imunologia , Complexo Antígeno-Anticorpo , Técnicas Biossensoriais , Meia-Vida , Humanos , Cinética , Técnicas Analíticas Microfluídicas/instrumentação , Troponina I/imunologiaRESUMO
Rational construction of flexible free-standing electrocatalysts featuring long-lasting durability, high efficiency, and wide temperature tolerance under harsh practical operations are fundamentally significant for commercial zinc-air batteries. Here, 3D flexible free-standing bifunctional membrane electrocatalysts composed of covalently cross-linked supramolecular polymer networks with nitrogen-deficient carbon nitride nanotubes are fabricated (referred to as PEMAC@NDCN) by a facile self-templated approach. PEMAC@NDCN demonstrates the lowest reversible oxygen bifunctional activity of 0.61 V with exceptional long-lasting durability, which outperforms those of commercial Pt/C and RuO2. Theoretical calculations and control experiments reveal the boosted electron transfer, electrolyte mass/ion transports, and abundant active surface site preferences. Moreover, the constructed alkaline Zn-air battery with PEMAC@NDCN air-cathode reveals superb power density, capacity, and discharge-charge cycling stability (over 2160 cycles) compared to the reference Pt/C + RuO2. Solid-state Zn-air batteries enable a high power density of 211 mW cm-2, energy density of 1056 Wh kg-1, stable charge-discharge cycling of 2580 cycles for 50 mA cm-2, and wide temperature tolerance from - 40 to 70 °C with retention of 86% capacity compared to room-temperature counterparts, illustrating prospects over harsh operations.
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To effectively control diabetes, a method to reliably measure glucose fluctuations in the body over given time periods needs to be developed. Current glucose monitoring systems depend on the substrate decomposition by an enzyme to detect the product; however, the enzyme activity significantly decays over time, which complicates analysis. In this study, we investigated an alternative method of glucose analysis based on antigen-antibody binding, which may be active over an extended period of time. To produce monoclonal antibodies, mice were immunized with molecular weight (M(W)) 10K dextran chemically conjugated with keyhole limpet hemocyanin. Since dextran contains glucose molecules polymerized via a 1,6-linkage, the produced antibodies had a binding selectivity that could discriminate biological glucose compounds with a 1,4-linkage. Three antibody clones with different affinities were screened using the M(W) 1K dextran-bovine serum albumin conjugates as the capture ligand. Among the antibodies tested, the antibody clone Glu 26 had the lowest affinity (K(A) = 3.56 × 10(6) M(-1)) and the most rapid dissociation (k(d) = 1.17 × 10(-2) s(-1)) with the polysaccharide immobilized on the solid surfaces. When glucose was added to the medium, the sensor signal was inversely proportional to the glucose concentration in a range between 10 and 1000 mg dL(-1), which covered the clinical range. Under the optimal conditions, the response time was about 3 min for association and 8 min for dissociation based on a 95% recovery of the final equilibrium.
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Anticorpos Monoclonais/imunologia , Técnicas Biossensoriais/métodos , Glucose/análise , Animais , Afinidade de Anticorpos , Reações Antígeno-Anticorpo , Bovinos , Dextranos/química , Hemocianinas/química , Hemocianinas/imunologia , Cinética , Ligantes , Camundongos , Soroalbumina Bovina/químicaRESUMO
Most immuno-analytical systems employ antibodies that do not readily dissociate upon binding to its partner antigen (i.e., target analyte; α2-macroglobulin as a model) and, thus, either need to be disposed of after one-time use or be reused after binding has been reset. To achieve a minimum-step analysis, an antibody that is capable of rapidly reversible binding with high affinity to an antigen was investigated in this study. This antibody was immobilized on the surface of a label-free sensor, which was combined with microfluidic channels, to demonstrate its applicability. The antibody was successively reused without a regeneration step under physiological conditions, offered specific analysis in the serum medium, and detected the analyte at concentrations as low as 0.1 ng mL(-1), which could further be enhanced by 100-fold. The sensor response reached 95% equilibrium after 8.3 and 14.9 min in average on each dose level for the concentration increase and decrease, respectively. The dynamic range covered a 5 logarithmic analyte concentration. Since the sampling size was in the nanolitre to millilitre range per day under the conditions used and the sensor may retain a long shelf-life, it could potentially be used in a clinical setting for long-term, on-line monitoring of diseases.
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Anticorpos Monoclonais/imunologia , Imunoensaio/métodos , alfa-Macroglobulinas/análise , Anticorpos Imobilizados/química , Anticorpos Imobilizados/imunologia , Anticorpos Monoclonais/química , Humanos , Técnicas Analíticas Microfluídicas/métodos , Ligação ProteicaRESUMO
Rechargeable aqueous zinc-air cells (ZACs) promise an extremely safe and high energy technology. However, they are still significantly limited by sluggish electrochemical kinetics and irreversibility originating from the parasitic reactions of the bifunctional catalysts and electrolytes. Here, we report the preferential in situ building of interfacial structures featuring the edge sites constituted by FeCo single/dual atoms with the integration of Co sites in the nitrogenized graphitic carbon frameworks (FeCo SAs@Co/N-GC) by electronic structure modulation approach. Compared to commercial Pt/C and RuO2, FeCo SAs@Co/N-GC reveals exceptional electrochemical performance, reversible redox kinetics, and durability toward oxygen reduction and evolution reactions under universal pH environments, i.e., alkaline, neutral, and acidic, due to synergistic effect at interfaces and preferred charge/mass transfer. The aqueous (alkaline, nonalkaline, and acidic electrolytes) ZACs constructed with a FeCo SAs@Co/N-GC cathode tolerate stable operations, have significant reversibility, and have the highest energy densities, outperforming those of noble metal counterparts and state-of-the-art ZACs in the ambient atmosphere. Additionally, flexible solid-state ZACs demonstrate excellent mechanical and electrochemical performances with a highest power density of 186 mW cm-2, specific capacity of 817 mAh gZn-1, energy density of 1017 Wh kgZn-1, and cycle life >680 cycles with extremely harsh operating conditions, which illustrates the great potential of triphasic catalyst for green energy storage technologies.
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This study is aimed at assessing the dimensional alterations occurring in the alveolar bone after premolar extraction in dogs with histomorphometric and histological analysis. After atraumatic premolar extraction, tooth-derived bone graft material was grafted in the extraction socket of the premolar region in the lower jaws of six dogs in two experimental groups. In the second experimental group, BM-MSCs were added together with the graft. The control was left untreated on the opposite side. After twelve weeks, all six animals were sacrificed. Differences in alveolar bone height crests lingually and buccally, and alveolar bone width at 1, 3, and 5 mm infracrestally, were examined. Histologic study revealed osteoconductive properties of tooth biomaterial. A statistically significant difference was detected between the test and control groups. In the test groups, a reduced loss of vertical and horizontal alveolar bone dimensions compared with the control group was observed. Tooth bone graft material may be considered useful for alveolar ridge preservation after tooth extraction, as it could limit the natural bone resorption process.