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Among the various hazardous substances, formaldehyde (HCHO), produced worldwide from wood furniture, dyeing auxiliaries, or as a preservative in consumer products, is harmful to human health. In this study, a sensitive room-temperature HCHO sensor, MTiNCs/Pd, has been developed by integrating Pd nanoclusters (PdNCs) into mesoporous MIL-125(Ti)-decorated TiO2 nanochannel arrays (TiNCs). Thanks to the enrichment effect of the mesoporous structure of MIL-125 and the large surface area offered by TiNCs, the resulting gas sensor accesses significantly enhanced HCHO adsorption capacity. The sufficient energetic active defects formed on PdNCs further allow an electron-extracting effect, thus effectively separating the photogenerated electrons and holes at the interface. The resulting HCHO sensor exhibits a short response/recovery time (37 s/12 s) and excellent sensitivity with a low limit of detection (4.51 ppb) under ultraviolet (UV) irradiation. More importantly, the cyclic redox reactions of Pdδ+ in PdNCs facilitated the regeneration of O2-(ads), thus ensuring a stable and excellent gas sensing performance even under a high-humidity environment. As a proof-of-principle of this design, a wearable gas sensing band is developed for the real-time and on-site detection of HCHO in cigarette smoke, with the potential as an independent device for environmental monitoring and other smart sensing systems.
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Surface-enhanced Raman scattering (SERS) spectroscopy is an effective technique that can reveal molecular structure and molecular interaction details. Semiconductor-based SERS platforms exhibit multifaceted tunability and unique selectivity to target molecules as well as high spectral reproducibility. However, the detection sensitivity of semiconductors is impeded by inferior SERS enhancement. Herein, a surface and interference co-enhanced Raman scattering (SICERS) platform based on corrugated TiO2 nanotube arrays (c-TiO2 NTs) was developed, and the coupling of structural regulation and photo-induced charge transfer (PICT) effectively optimized the SERS performance of the semiconductor substrate. Due to the regularly oscillating optical properties of the c-TiO2 NTs, well-defined interference patterns were generated and the local electric field was significantly increased, which greatly promoted both the electromagnetic mechanism and PICT processes. The c-TiO2 NTs were subsequently applied as a highly sensitive SICERS substrate to investigate the mechanism of temperature influence on enantioselective identification. This identification process is related to the existence of temperature-sensitive hydrogen bonds and π-π interaction. This work demonstrates a simply prepared, low-cost, and sensitive SERS substrate that enables better investigation into molecular identification.
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As pure antipodes may differ in biological interactions, pharmacology, and toxicity, discrimination of enantiomers is important in the pharmaceutical and agrochemical industries. Two major challenges in enantiomer determination are transducing and amplifying the distinct chiral-recognition signals. In this study, a light-sensitive organic photoelectrochemical transistor (OPECT) with homochiral character is developed for enantiomer discrimination. Demonstrated with the discrimination of glucose enantiomers, the photoelectrochemically active gate electrode is prepared by integrating Au nanoparticles (AuNPs) and a chiral Cu(II)-metal-organic framework (c-CuMOF) onto TiO2 nanotube arrays (TNT). The captured glucose enantiomers are oxidized to hydrogen peroxide (H2O2) by the oxidase-mimicking AuNPs-loaded c-CuMOF. Based on the confinement effect of the mesopocket structure of the c-CuMOF and the remarkable charge transfer ability of the 1D nanotubular architecture, variations in H2O2 yield are translated into significant changes in OPECT drain currents (ID) by inducing a catalytic precipitation reaction. Variations in ID confer a sensitive discrimination of glucose enantiomers with a limit of detection (LOD) of 0.07 µM for L-Glu and 0.05 µM for D-Glu. This enantiomer-driven gate electrode response strategy not only provides a new route for enantiomer identification, but also helps to understand the origin of the high stereoselectivity in living systems.
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Técnicas Biosensibles , Técnicas Electroquímicas , Glucosa , Oro , Peróxido de Hidrógeno , Límite de Detección , Nanopartículas del Metal , Estructuras Metalorgánicas , Estructuras Metalorgánicas/química , Técnicas Biosensibles/instrumentación , Oro/química , Técnicas Electroquímicas/instrumentación , Estereoisomerismo , Nanopartículas del Metal/química , Glucosa/análisis , Glucosa/química , Glucosa/aislamiento & purificación , Peróxido de Hidrógeno/química , Peróxido de Hidrógeno/análisis , Titanio/química , Transistores Electrónicos , Cobre/química , Luz , Monosacáridos/análisis , Monosacáridos/química , Nanotubos/químicaRESUMEN
Alternative energy sources are required due to the decline in fossil fuel resources. Therefore, devices that utilize hydrovoltaic technology and light energy have drawn widespread attention because they are emission-free and solar energy is inexhaustible. However, previous investigations mainly focused on accelerating the water evaporation rate at the electrode interface. Here, a cooperative photoelectrochemical effect on a hydrovoltaic chip is achieved using NH2-MIL-125-modified TiO2 nanotube arrays (NTs). This device demonstrated significantly improved evaporation-triggered electricity generation. Under LED illumination, the open-circuit voltage (VOC) of the NH2-MIL-125/TiO2NTs active layer of the hydrovoltaic chip was enhanced by 90.3% (up to 400.2 mV). Furthermore, the prepared hydrovoltaic chip showed good high-salinity tolerance, maintaining 74.6% of its performance even in 5 M NaCl. By introducing a Schiff-based reaction between the active layer and formaldehyde, a fully integrated flexible sensor was successfully fabricated for formaldehyde monitoring, and a low limit of detection of 5.2 × 10-9 M was achieved. This novel strategy for improving the performance of hydrovoltaic devices offers a completely new general approach to construct self-powered devices for point-of-care sensing.
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Técnicas Electroquímicas , Formaldehído , Titanio , Formaldehído/análisis , Formaldehído/química , Titanio/química , Técnicas Electroquímicas/métodos , Técnicas Electroquímicas/instrumentación , Nanotubos/química , Salinidad , Procesos Fotoquímicos , Electrodos , Límite de DetecciónRESUMEN
The development of sensitive, selective, and rapid methods to detect bacteria in complex media is essential to ensuring human health. Virulence factors, particularly pore-forming toxins (PFTs) secreted by pathogenic bacteria, play a crucial role in bacterial diseases and serve as indicators of disease severity. In this study, a nanochannel-based label-free electrochemical sensing platform was developed for the detection of specific pathogenic bacteria based on their secreted PFTs. In this design, wood substrate channels were functionalized with a Fe-based metal-organic framework (FeMOF) and then protected with a layer of phosphatidylcholine (PC)-based phospholipid membrane (PM) that serves as a peroxidase mimetic and a channel gatekeeper, respectively. Using Staphylococcus aureus (S. aureus) as the model bacteria, the PC-specific PFTs secreted by S. aureus perforate the PM layer. Now exposed to the FeMOF, uncharged 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) molecules in the electrolyte undergo oxidation to cationic products (ABTSâ¢+). The measured transmembrane ionic current indicates the presence of S. aureus and methicillin-resistant S. aureus (MRSA) with a low detection limit of 3 cfu mL-1. Besides excellent specificity, this sensing approach exhibits satisfactory performance for the detection of target bacteria in the complex media of food.
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Toxinas Bacterianas , Técnicas Biosensibles , Técnicas Electroquímicas , Toxinas Bacterianas/metabolismo , Toxinas Bacterianas/análisis , Estructuras Metalorgánicas/química , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Peroxidasa/metabolismo , Peroxidasa/química , Staphylococcus aureus/aislamiento & purificación , Staphylococcus aureus/metabolismoRESUMEN
Chemiresistive gas sensors based on metal oxides have been widely applied in industrial monitoring, medical diagnosis, environmental pollutant detection, and food safety. To further enhance the gas sensing performance, researchers have worked to modify the structure and function of the material so that it can adapt to different gas types and environmental conditions. Among the numerous gas-sensitive materials, n-type TiO2 semiconductors are a focus of attention for their high stability, excellent biosafety, controllable carrier concentration, and low manufacturing cost. This Perspective first introduces the sensing mechanism of TiO2 nanostructures and composite TiO2-based nanomaterials and then analyzes the relationship between their gas-sensitive properties and their structure and composition, focusing also on technical issues such as doping, heterojunctions, and functional applications. The applications and challenges of TiO2-based nanostructured gas sensors in food safety, medical diagnosis, environmental detection, and other fields are also summarized in detail. Finally, in the context of their practical application challenges, future development technologies and new sensing concepts are explored, providing new ideas and directions for the development of multifunctional intelligent gas sensors in various application fields.
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Gases , Nanoestructuras , Titanio , Titanio/química , Gases/análisis , Gases/química , Nanoestructuras/química , Humanos , SemiconductoresRESUMEN
In all their applications, gas sensors should satisfy several requirements, including low cost, reduced energy consumption, fast response/recovery, high sensitivity, and reliability in a broad humidity range. Unfortunately, the fast response/recovery and sensing reliability under high humidity conditions are often still missing, especially those working at room temperature. In this study, a humidity-resistant gas sensor with an ultrafast response/recovery rate was designed by integrating a defect-rich semiconducting sensing interface and a self-assembled monolayer (SAM) with controllable wettability. As a proof-of-concept application, ammonia (NH3), one of the atmospheric and indoor pollutants, was selected as the target gas. The decoration of interconnected defective CeO2 nanowires on spaced TiO2 nanotube arrays (NTAs) provided superior NH3 sensing performances. Moreover, we showed that manipulating the functional end group of SAMs is an efficient and simple method to adjust the wettability, by which 86% sensitivity retention with an ultrafast response (within 5 s) and a low limit of detection (45 ppb) were achieved even at 75% relative humidity and room temperature. This work provides a new route toward the comprehensive design and application of metal oxide semiconductors for trace gas monitoring under harsh conditions, such as those of agricultural, environmental, and industrial fields.
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Amoníaco , Nanotubos , Humedad , Reproducibilidad de los Resultados , HumectabilidadRESUMEN
BACKGROUND: Proteases secreted by Trichinella spiralis intestinal infective larvae (IIL) play an important role in larval invasion and pathogenesis. However, the mechanism through which proteases mediate larval invasion of intestinal epithelial cells (IECs) remains unclear. A novel T. spiralis trypsin (TsTryp) was identified in IIL excretory/secretory (ES) proteins. It was an early and highly expressed protease at IIL stage, and had the potential as an early diagnostic antigen. The aim of this study was to investigate the biological characteristics of this novel TsTryp, its role in larval invasion of gut epithelium, and the mechanisms involved. METHODOLOGY/PRINCIPAL FINDING: TsTryp with C-terminal domain was cloned and expressed in Escherichia coli BL21 (DE3), and the rTsTryp had the enzymatic activity of natural trypsin, but it could not directly degrade gut tight junctions (TJs) proteins. qPCR and western blotting showed that TsTryp was highly expressed at the invasive IIL stage. Immunofluorescence assay (IFA), ELISA and Far Western blotting revealed that rTsTryp specifically bound to IECs, and confocal microscopy showed that the binding of rTsTryp with IECs was mainly localized in the cytomembrane. Co-immunoprecipitation (Co-IP) confirmed that rTsTryp bound to protease activated receptors 2 (PAR2) in Caco-2 cells. rTsTryp binding to PAR2 resulted in decreased expression levels of ZO-1 and occludin and increased paracellular permeability in Caco-2 monolayers by activating the extracellular regulated protein kinases 1/2 (ERK1/2) pathway. rTsTryp decreased TJs expression and increased epithelial permeability, which could be abrogated by the PAR2 antagonist AZ3451 and ERK1/2 inhibitor PD98059. rTsTryp facilitated larval invasion of IECs, and anti-rTsTryp antibodies inhibited invasion. Both inhibitors impeded larval invasion and alleviated intestinal inflammation in vitro and in vivo. CONCLUSIONS: TsTryp binding to PAR2 activated the ERK1/2 pathway, decreased the expression of gut TJs proteins, disrupted epithelial integrity and barrier function, and consequently mediated larval invasion of the gut mucosa. Therefore, rTsTryp could be regarded as a potential vaccine target for blocking T. spiralis invasion and infection.
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Receptor PAR-2 , Trichinella spiralis , Triquinelosis , Animales , Humanos , Ratones , Células CACO-2 , Epitelio/metabolismo , Proteínas del Helminto/metabolismo , Larva/fisiología , Sistema de Señalización de MAP Quinasas , Ratones Endogámicos BALB C , Proteínas Quinasas , Trichinella spiralis/metabolismo , Trichinella spiralis/patogenicidad , Triquinelosis/genética , Triquinelosis/metabolismo , Tripsina/metabolismo , Receptor PAR-2/metabolismoRESUMEN
BACKGROUND: Gut epithelium is the first natural barrier against Trichinella spiralis larval invasion, but the mechanism by which larval penetration of gut epithelium is not completely elucidated. Previous studies showed that proteases secreted by T. spiralis intestinal infective larvae (IIL) degraded tight junctions (TJs) proteins of gut epithelium and mediated larval invasion. A new T. spiralis serine proteinase (TsSPc) was identified in the IIL surface proteins and ES proteins, rTsSPc bound to the intestinal epithelial cell (IECs) and promoted larval invasion of IECs. The aim of this study was to characterize the interacted proteins of TsSPc and IECs, and to investigate the molecular mechanisms of TsSPc mediating larval invasion of gut mucosa. METHODOLOGY/PRINCIPAL FINDING: IIFT results showed natural TsSPc was detected in infected murine intestine at 6, 12 hours post infection (hpi) and 3 dpi. The results of GST pull-down, mass spectrometry (MS) and Co-IP indicated that rTsSPc bound and interacted specifically with receptor for activated protein C kinase 1 (RACK1) in Caco-2 cells. rTsSPc did not directly hydrolyze the TJs proteins. qPCR and Western blot showed that rTsSPc up-regulated RACK1 expression, activated MAPK/ERK1/2 pathway, reduced the expression levels of gut TJs (occludin and claudin-1) and adherent protein E-cad, increased the paracellular permeability and damaged the integrity of intestinal epithelial barrier. Moreover, the RACK1 inhibitor HO and ERK1/2 pathway inhibitor PD98059 abolished the rTsSPc activating ERK1/2 pathway, they also inhibited and abrogated the rTsSPc down-regulating expression of occludin, claudin-1 and E-cad in Caco-2 monolayer and infected murine intestine, impeded larval invasion and improved intestinal epithelial integrity and barrier function, reduced intestinal worm burdens and alleviated intestinal inflammation. CONCLUSIONS: rTsSPc bound to RACK1 receptor in gut epithelium, activated MAPK/ERK1/2 pathway, decreased the expression of gut epithelial TJs proteins and disrupted the epithelial integrity, consequently mediated T. spiralis larval invasion of gut epithelium. The results are valuable to understand T. spiralis invasion mechanism, and TsSPc might be regarded as a vaccine target against T. spiralis invasion and infection.
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Trichinella spiralis , Triquinelosis , Humanos , Animales , Ratones , Larva/fisiología , Serina Proteasas/genética , Células CACO-2 , Claudina-1/metabolismo , Sistema de Señalización de MAP Quinasas , Ocludina/metabolismo , Proteínas del Helminto/metabolismo , Células Epiteliales/metabolismo , Ratones Endogámicos BALB C , Mucosa Intestinal/metabolismo , Receptores de Cinasa C Activada/metabolismo , Proteínas de Neoplasias/genéticaRESUMEN
OBJECTIVES: To understand the growth and development status and differences between small for gestational age (SGA) and appropriate for gestational age (AGA) preterm infants during corrected ages 0-24 months, and to provide a basis for early health interventions for preterm infants. METHODS: A retrospective study was conducted, selecting 824 preterm infants who received regular health care at the Guangzhou Women and Children's Medical Center from July 2019 to July 2022, including 144 SGA and 680 AGA infants. The growth data of SGA and AGA groups at birth and corrected ages 0-24 months were analyzed and compared. RESULTS: The SGA group had significantly lower weight and length than the AGA group at corrected ages 0-18 months (P<0.05), while there were no significant differences between the two groups at corrected age 24 months (P>0.05). At corrected age 24 months, 85% (34/40) of SGA and 79% (74/94) of AGA preterm infants achieved catch-up growth. Stratified analysis by gestational age showed that there were significant differences in weight and length at corrected ages 0-9 months between the SGA subgroup with gestational age <34 weeks and the AGA subgroups with gestational age <34 weeks and 34 weeks (P<0.05). In addition, the weight and length of the SGA subgroup with gestational age 34 weeks showed significant differences compared to the AGA subgroups with gestational age <34 weeks and 34 weeks at corrected ages 0-18 months and corrected ages 0-12 months, respectively (P<0.05). Catch-up growth for SGA infants with gestational age <34 weeks and 34 weeks mainly occurred at corrected ages 0-12 months and corrected ages 0-18 months, respectively. CONCLUSIONS: SGA infants exhibit delayed early-life physical growth compared to AGA infants, but can achieve a higher proportion of catch-up growth by corrected age 24 months than AGA infants. Catch-up growth can be achieved earlier in SGA infants with a gestational age of <34 weeks compared to those with 34 weeks.
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Recien Nacido Prematuro , Recién Nacido Pequeño para la Edad Gestacional , Recién Nacido , Niño , Lactante , Femenino , Humanos , Preescolar , Edad Gestacional , Estudios Longitudinales , Estudios RetrospectivosRESUMEN
Adenosine triphosphate (ATP) universally exists in all living organisms and holds a paramount role as a fundamental energy molecule in daily life. The abnormal concentration of ATP is closely related to many diseases, making the highly efficient detection of ATP very urgent. In this study, a dual-mode sensing system was developed to detect ATP sensitively and selectively via both DPV and fluorescence (FL) techniques, based on the strong interaction of ATP and Zn (II) nodes of zeolitic imidazolate framework-90 (ZIF-90). The disassembly of ZIF-90 further induced the subsequent release of pre-loaded rhodamine B (RhB). Benefitting from the robust host-guest recognition of ß-cyclodextrin (ß-CD) towards RhB, an enzyme-free and highly specific DPV detection strategy was established with the linear detecting range of 10.0-1.0 × 108 pM and the limit of detection (LOD) as low as 0.13 pM. Meanwhile, the FL sensing mode based on RhB exhibits comparable sensing performance with the linearity range of 10.0-1.0 × 107 pM and the LOD of 0.29 pM. Furthermore, the enzyme-free ATP sensing system exhibit outstanding long-term storage stability. The two-mode sensing platform was successfully applied to detect the ATP in human serum samples with the yielded result highly agree with the results of commercial ELISA kits. This dual-mode sensing platform is inspiring and paves the road for developing high-performance biosensor, demonstrating enormous potential for vitro diagnosis and practice clinic.
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Estructuras Metalorgánicas , Nanopartículas , Zeolitas , Humanos , Adenosina Trifosfato , Ensayo de Inmunoadsorción Enzimática , Límite de DetecciónRESUMEN
Large-capacity energy storage devices are attracting widespread research attention. However, the decreased capacity of these devices due to cold weather is a huge obstacle for their practical use. In this study, an electrochemical self-adaptive reconstructed Cux S/Cu(OH)2 -based symmetric energy storage device is proposed. This device provides a satisfactorily enhanced photothermal capacity under solar irradiation. After electrochemical reconstruction treatment, the morphological structure is rearranged and the Cux S component is partially converted to electrochemically active Cu(OH)2 with the introduction of a large number of active sites. The resulting Cux S/Cu(OH)2 electrode provides a significant capacitance of 115.2 F cm-2 at 5 mA cm-2 . More importantly, its wide working potential range and superior photo-to-thermal conversion ability endow Cux S/Cu(OH)2 with superb performance as full-purpose photothermally enhanced capacitance electrodes. Under solar irradiation, the surface temperature of Cux S/Cu(OH)2 is elevated by 76.6 °C in only 30 s, and the capacitance is boosted to 230.4% of the original capacitance at a low temperature. Furthermore, the assembled symmetric energy storage device also delivers a photothermal capacitance enhancement of 200.3% under 15 min solar irradiation.
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Previous studies showed that Trichinella spiralis galectin (Tsgal) facilitates larval invasion of intestinal epithelium cells (IECs). However, IEC proteins binding with Tsgal were not identified, and the mechanism by which Tsgal promotes larval invasion is not clear. Toll-like receptors (TLRs) are protein receptors responsible for recognition of pathogens. The aim of this study was to investigate whether recombinant Tsgal (rTsgal) binds to TLR-4, activates inflammatory pathway in gut epithelium and mediates T. spiralis invasion. Indirect immunofluorescence (IIF), GST pull-down and co-immunoprecipitation (Co-IP) assays confirmed specific binding between rTsgal and TLR-4 in Caco-2 cells. qPCR and Western blotting showed that binding of rTsgal with TLR-4 up-regulated the TLR-4 transcription and expression in Caco-2 cells, and activated p-NF-κB p65 and p-ERK1/2. Activation of inflammatory pathway TLR-4/MAPK-NF-κB by rTsgal up-regulated pro-inflammatory cytokines (IL-1ß and IL-6) and down-regulated anti-inflammatory cytokine TGF-ß in Caco-2 cells, and induced intestinal inflammation. TAK-242 (TLR-4 inhibitor) and PDTC (NF-κB inhibitor) significantly inhibited the activation of TLR-4 and MAPK-NF-κB pathway. Moreover, the two inhibitors also inhibited IL-1ß and IL-6 expression, and increased TGF-ß expression in Caco-2 cells. In T. spiralis infected mice, the two inhibitors also inhibited the activation of TLR-4/MAPK-NF-κB pathway, ameliorated intestinal inflammation, impeded larval invasion of gut mucosa and reduced intestinal adult burdens. The results showed that rTsgal binding to TLR-4 in gut epithelium activated MAPK-NF-κB signaling pathway, induced the expression of TLR-4 and pro-inflammatory cytokines, and mediated larval invasion. Tsgal might be regarded as a candidate molecular target of vaccine against T. spiralis enteral invasive stage.
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Trichinella spiralis , Ratones , Animales , Humanos , Trichinella spiralis/fisiología , Receptor Toll-Like 4/genética , FN-kappa B/metabolismo , Células CACO-2 , Larva/fisiología , Galectinas , Interleucina-6 , Mucosa Intestinal/metabolismo , Citocinas/metabolismo , Inflamación/veterinaria , Factor de Crecimiento Transformador betaRESUMEN
In this study, we developed a gas sensing platform that can sensitively and specifically detect trace H2S in a high-humidity atmosphere at RT. Upon integrating a carbon nitride (C3N4) nanofilm and molybdenum dioxide (MoO2) nanosheets onto nanojungle-like TiO2 nanotube arrays (TiNTs), the fabricated chemiresistor showed rapid response (38 s)/recovery (58 s) abilities and remarkable detection sensitivity for H2S at concentrations down to 2 ppb, with an estimated detection limit of 1.13 ppb at RT and room-environmental light (REL). Importantly, the gas sensor exhibited satisfactory H2S sensing performance even in dark conditions with a response of 1.9 at 200 ppb. In this design, apart from the architectural advantages of the nanojungle-like TiNTs for accelerating the gas flow efficiency and the abundant sensing sites provided by the C3N4 film, the MoO2 nanosheets act as the essential electron pump not only for the H2S response but also for the subsequent recovery process in air. After employing the MoO2 pump onto C3N4/TiNTs, the response time and recovery time of the system are shortened to â¼35 and â¼11%, respectively. Moreover, we demonstrated the good performance of the flexible gas sensor in detecting trace H2S in human exhaled breath with good humidity resistance. These results highlight the possibility of designing chemiresistors operating in RT and REL conditions and to use these environmentally friendly TiO2-based sensors in real applications.
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Líquidos Corporales , Humanos , Temperatura , Electrones , EspiraciónRESUMEN
Formaldehyde is ubiquitously found in the environment, meaning that real-time monitoring of formaldehyde, particularly indoors, can have a significant impact on human health. However, the performance of commercially available interdigital electrode-based sensors is a compromise between active material loading and steric hindrance. In this work, a spaced TiO2 nanotube array (NTA) was exploited as a scaffold and electron collector in a formaldehyde sensor for the first time. A Sn-based metal-organic framework was successfully decorated on the inside and outside of TiO2 nanotube walls by a facile solvothermal decoration strategy. This was followed by regulated calcination, which successfully integrated the preconcentration effect of a porous Sn-based metal-organic framework (SnMOF) structure and highly active SnO2 nanocrystals into the spaced TiO2 NTA to form a Schottky heterojunction-type gas sensor. This SnMOF/SnO2@TiO2 NTA sensor achieved a high room-temperature formaldehyde response (1.7 at 6 ppm) with a fast response (4.0 s) and recovery (2.5 s) times. This work provides a new platform for preparing alternatives to interdigital electrode-based sensors and offers an effective strategy for achieving target preconcentrations for gas sensing processes. The as-prepared SnMOF/SnO2@TiO2 NTA sensor demonstrated excellent sensitivity, stability, reproducibility, flexibility, and convenience, showing excellent potential as a miniaturized device for medical diagnosis, environmental monitoring, and other intelligent sensing systems.
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Estructuras Metalorgánicas , Nanotubos , Humanos , Reproducibilidad de los Resultados , Temperatura , FormaldehídoRESUMEN
Alzheimer's disease (AD) is an irreversible brain disorder, which has been found to be associated with neurotoxic amyloid-ß oligomers (AßO). The early diagnosis of AD is still a great challenge. Herein, inspired by the hierarchical channel structure of natural wood, we design and demonstrate a low-cost and sensitive wood channel-based fluidic membrane for electrochemical sensing of AßO1-42. In this design, Zn/Cu-2-methylimidazole (Zn/Cu-Hmim) with artificial peroxidase (POD)-like activity was asymmetrically fabricated at one side of the wood channels by biomimetic mineralization and a subsequent ion exchange reaction. The strong affinity between Cu(II) and AßO1-42 enables Cu(II) species in Zn/Cu-Hmim to be extracted by AßO1-42, thus suppressing the POD-like performance via Zn/Cu-Hmim disassembly. Using Zn/Cu-Hmim to catalyze the oxidation reaction of 2,2'-diazo-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) by H2O2, the current-voltage (I-V) properties of wood channels are influenced by the generated oxidation product (ABTSâ¢+), thus providing information useful for the quantitative analysis of AßO1-42. Importantly, the three aggregation states of Aß1-42 (AßM1-42, AßO1-42, and AßF1-42) can also be identified, owing to the affinity difference and available reaction sites. The proposed wood membrane provides a novel, assessable, and scalable channel device to develop sensitive electrochemical sensors; moreover, the sustainable wood materials represent alternative candidates for developing channel-structured sensing platforms.
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Enfermedad de Alzheimer , Péptidos beta-Amiloides , Péptidos beta-Amiloides/química , Peróxido de Hidrógeno , Madera/química , Enfermedad de Alzheimer/diagnóstico , Antioxidantes , Cobre/químicaRESUMEN
C-type lectin (CTL) is a protein that binds to saccharides and plays an important role in parasite adhesion, host cell invasion and immune evasion. Previous studies showed that recombinant T. spiralis C-type lectin (rTsCTL) promotes larval invasion of intestinal epithelium cells (IEC), whereas anti-rTsCTL antibodies inhibits larval invasion. Syndecan-1 (SDC-1) is a member of the heparan sulfate proteoglycan family which is mainly expressed on the surface of IEC and in extracellular matrices where they interact with a plethora of ligands. SDC-1 has a principal role in maintaining cell morphogenesis, establishing cell-cell adhesions, and regulating the gut mucosal barrier. The aim of this study was to investigate whether rTsCTL binds to SDC-1 on IEC, and the binding of rTsCTL with SDC-1 promotes larval invasion and its mechanism. IFA results show that rTsCTL and SDC-1 co-localized on Caco-2 cell membrane. GST pull-down and Co-IP verified the direct interaction between rTsCTL and SDC-1 on Caco-2 cells. qPCR and Western blotting revealed that rTsCTL binding to SDC-1 increased the expression of SDC-1 and claudin-2, and reduced the expression of occludin and claudin-1 in Caco-2 cells incubated with rTsCTL via the STAT3 pathway. ß-Xyloside (a syndecan-1 synthesis inhibitor) and Stattic (a STAT3 inhibitor) significantly inhibited rTsCTL binding to syndecan-1 in Caco-2 cells and activation of the STAT3 pathway, abrogated the effects of rTsCTL on the expression of gut tight junctions, and impeded larval invasion. The results demonstrate that binding of rTsCTL to SDC-1 on Caco-2 cells activated the STAT3 pathway, decreased gut tight junction expression, damaged the integrity of the gut epithelial barrier, and mediated T. spiralis invasion of the gut mucosa. TsCTL might be regarded as a candidate vaccine target against T. spiralis invasion and infection.
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Trichinella spiralis , Triquinelosis , Animales , Ratones , Humanos , Trichinella spiralis/fisiología , Triquinelosis/parasitología , Triquinelosis/veterinaria , Larva/fisiología , Células CACO-2 , Sindecano-1/genética , Sindecano-1/metabolismo , Mucosa Intestinal/metabolismo , Células Epiteliales/metabolismo , Ratones Endogámicos BALB CRESUMEN
Enantioselective identification of chiral molecules is regarded as one of the key issues in biological and medical sciences because of their configuration-dependent effects on biological systems. In this study, we developed an electrochemical platform based on a tandem recognition-reaction zone design in TiO2 nanochannels for the specific recognition of reducing enantiomers. In this system, MIL-125(Ti) Ti-metal-organic frameworks, in situ grown in TiO2 nanochannels, provided a homochiral recognition environment via postmodification with l-tartaric acid (l-TA); MnO2 nanosheets possessing both glucose oxidase (GOD)- and peroxidase (POD)-mimicking activities served as the target-reactive zone at the end of the nanochannels. The use of penicillamine (Pen) enantiomers as model-reducing targets facilitated the passage of d-Pen through the homochiral recognition zone, owing to its lower affinity with l-TA. The passed Pen molecules reached the responsive zone and induced a target concentration-dependent MnO2 disassembly. Such target recognition event impaired the cascade GOD- and POD-like activities of MnO2. Combining the enantioselectivity of the recognition nanochannels with the cascade enzyme-like activity of MnO2 toward glucose and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate), the quantitative identification of l- and d-Pen was achieved through the changes in transmembrane ionic current induced by the generated charged products. This recognition-reaction zone design paves an effective way for developing a promising electrochemical platform for the identification of reducing enantiomers with improved selectivity and sensitivity.
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Compuestos de Manganeso , Óxidos , Estereoisomerismo , Glucosa Oxidasa , PenicilaminaRESUMEN
BACKGROUND: A novel serine proteinase of Trichinells spiralis (TsSPc) has been identified in the excretion/secretion (ES) antigens, but its role in larval invasion is unclear. The aim of this study was to clone and express TsSPc, identify its biological and biochemical characteristics, and investigate its role on larval invasion of gut epithelium during T. spiralis infection. METHODOLOGY/PRINCIPAL FINDINGS: TsSPc has a functional domain of serine proteinase, and its tertiary structure consists of three amino acid residues (His88, Asp139 and Ser229) forming a pocket like functional domain. Recombinant TsSPc (rTsSPc) was expressed and purified. The rTsSPc has good immunogenicity. On Western blot analysis, rTsSPc was recognized by infection serum and anti-rTsSPc serum, natural TsSPc in crude and ES antigens was identified by anti-rTsSPc serum. The results of qPCR, Western blot and indirect immunofluorescence test (IIFT) showed that TsSPc was expressed at diverse stage worms, and mainly localized at cuticle, stichosome and intrauterine embryos of this nematode. The rTsSPc had enzymatic activity of native serine protease, which hydrolyzed the substrate BAEE, casein and collagen I. After site directed mutation of enzymatic active sites of TsSPc, its antigenicity did not change but the enzyme activity was fully lost. rTsSPc specifically bound to intestinal epithelium cells (IECs) and the binding sites were mainly localized in cell membrane and cytoplasm. rTsSPc accelerated larval invasion of IECs, whereas anti-rTsSPc antibodies and TsSPc-specific dsRNA obviously hindered larval invasion. CONCLUSIONS: TsSPc was a surface and secretory proteinase of the parasite, participated in larval invasion of gut epithelium, and may be considered as a candidate vaccine target molecule against Trichinella intrusion and infection.
Asunto(s)
Trichinella spiralis , Trichinella , Animales , Serina Proteasas/genética , Trichinella spiralis/genética , Serina Endopeptidasas , EpitelioRESUMEN
Glutathione (GSH) plays a vital role in many physiological processes, and its abnormal levels have been found to be associated with several diseases. In contrast to traditional methods using electron donor-containing electrolytes for photoelectrochemical (PEC) sensing, in this study, a target-driven electron donor generation in a PEC electrode was developed to detect GSH. Using well-aligned TiO2 nanotube arrays (TNTs) as the PEC substrate, mesoporous MIL-125(Ti) was grown in the TNTs through an in situ solvothermal method and subsequent two-step annealing treatment. The accommodation capacity of mesoporous MIL-125(Ti) allows a well loading of cystine and Pt nanoclusters (NCs). Taking advantage of the specific cleavage ability of disulfide bonds by GSH, cystine was converted to cysteine, which served as the electron donor for the PEC process. Benefiting from the confinement effect of mesoporous MIL-125(Ti), cysteine was effectively oxidized to cysteine sulfinic acid by the photogenerated holes. Importantly, the highly active Pt NCs decorated in the mesopores not only improved the charge transfer but also accelerated the above oxidation reaction. The synergistic effect of these factors enabled the efficient separation of the photogenerated electron-hole pairs, which induced a significant photocurrent increase and in turn led to the high-sensitivity detection of GSH. Consequently, the proposed PEC biosensor exhibited excellent performance in the detection of GSH in serum specimens. The target-driven electron donor generation designed in this study might open a new route for developing sensitive and selective PEC biosensors with application in complex biological environments.