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Solid-liquid-gas reactions are ubiquitous and are encountered in both nature and industrial processes1-4. A comprehensive description of gas transport in liquid and following reactions at the solid-liquid-gas interface, which is substantial in regard to achieving enhanced triple-phase reactions, remains unavailable. Here, we report a real-time observation of the accelerated etching of gold nanorods with oxygen nanobubbles in aqueous hydrobromic acid using liquid-cell transmission electron microscopy. Our observations reveal that when an oxygen nanobubble is close to a nanorod below the critical distance (~1 nm), the local etching rate is significantly enhanced by over one order of magnitude. Molecular dynamics simulation results show that the strong attractive van der Waals interaction between the gold nanorod and oxygen molecules facilitates the transport of oxygen through the thin liquid layer to the gold surface and thus plays a crucial role in increasing the etching rate. This result sheds light on the rational design of solid-liquid-gas reactions for enhanced activities.
Assuntos
Ouro , Água , Microscopia Eletrônica de Transmissão , Oxigênio , Propriedades de SuperfícieRESUMO
BACKGROUND: Increasing evidence suggests that heroin addiction may be related to the dysfunction among the triple brain network (default mode network [DMN], salience network [SN] and executive control network [ECN]). However, the characteristics of glucose metabolism and metabolic connectivity among core regions of the triple brain network remain unknown. Therefore, we hypothesized that individuals with heroin dependence would show abnormal glucose metabolism and accompanied abnormal metabolic connectivity within the triple brain network. METHODS: Individuals with heroin dependence and healthy controls matched for age and sex underwent integrated positron emission tomography/magnetic resonance imaging (PET/MRI). Differences in glucose metabolism and metabolic connectivity among the DMN, SN and ECN were analyzed based on 18F-fluorodeoxyglucose PET and resting-state fMRI data. RESULTS: We included 36 individuals with heroin dependence and 30 matched healthy controls in our study. The heroin dependence group showed a significant reduction of glucose metabolism in the bilateral anterior insula (AI) and inferior parietal lobule (IPL), and a significantly decreased metabolic connectivity between the right AI and the left dorsolateral prefrontal cortex (DLPFC). The daily dose of methadone was negatively correlated with glucose metabolism of the right AI and right IPL. LIMITATIONS: The results revealed the glucose metabolism alterations and metabolic connectivity only within the triple brain network in individuals with heroin dependence; additional brain networks should be investigated in future studies. Although methadone is an opioid with a similar neurophysiological mechanism as heroin, the specific chronic effects of methadone on cerebral metabolism and metabolic connectivity should also be investigated in future studies. CONCLUSION: Our findings suggest that long-term opioid use might, to some extent, be associated with reduced synergistic ability between the SN and ECN, which may be associated with the dysfunction of cognitive control. In particular, the right AI, which showed hypometabolism and related reduction in SN-ECN metabolic connectivity, should receive increasing attention in future studies.
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Dependência de Heroína , Imageamento por Ressonância Magnética , Humanos , Dependência de Heroína/diagnóstico por imagem , Analgésicos Opioides , Glucose , Metadona , Tomografia por Emissão de PósitronsRESUMO
Bladder cancer (BC) is one of the most common cancers in the world, with high morbidity and mortality. It is essential to develop a non-invasive, highly accurate, and simple method for BC diagnosis. This work proposed a fluorescent biosensor based on inorganic nanoflares combined with a DNAzyme walker for the simultaneous detection of BC exosomal microRNAs (miRNAs). This biosensor was constructed on the Au nanoparticle (AuNP) modified with the carbon dot (CD)-labeled substrates and DNAzyme strands (AuNP@CDs inorganic nanoflares-DNAzyme, APCD). In the presence of target miRNAs, DNAzyme was activated and then cleaved the CD-labeled substrates and automatically walked along the AuNP, allowing fluorescence recovery. Due to the structure and functional composition, the APCD biosensors demonstrated high sensitivity and specificity, with the reached limit of detection for a single miRNA at the femtomolar level and wide linear range from 50 fM to 10 nM. Furthermore, the simultaneous analysis of BC-related exosomal miR-133b and miR-135b in clinical serum specimens was achieved and consistent with qRT-PCR, suggesting it is a potential method for the diagnosis of BC and other cancers.
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Técnicas Biossensoriais , DNA Catalítico , Nanopartículas Metálicas , MicroRNAs , Neoplasias da Bexiga Urinária , Técnicas Biossensoriais/métodos , DNA Catalítico/química , Ouro/química , Humanos , Limite de Detecção , Nanopartículas Metálicas/química , MicroRNAs/análise , Neoplasias da Bexiga Urinária/diagnóstico , Neoplasias da Bexiga Urinária/genéticaRESUMO
Glioblastoma (GBM) is the most fatal and common type of primary malignant tumors in central nervous system. Chemotherapy drugs are difficult to reach the encephalic region effectively due to blood-brain barrier (BBB), but functional nanoparticle drug carriers can help to solve the problem. Herein, we developed a controllable drug carrier called temozolomide magnetic temperature-sensitive liposomes (TMZ/Fe-TSL) to investigate its feasibility and molecular mechanisms on GBM. Our research found TMZ/Fe-TSL exposed to alternating magnetic field (AMF) could induce significantly GBM cell death and promote the production of ROS. It also showed that the expression of NLRP3, CASP1 and N-GSDMD was upregulated compared to the control group, while the expression of CASP3 showed a reverse change. The results indicated that TMZ/Fe-TSL exposed to the AMF was capable of inducing GBM cells death. And the way and mechanisms of cell death may involve in ROS and pyroptosis, but not apoptosis.
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Neoplasias Encefálicas , Glioblastoma , Apoptose , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/metabolismo , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos , Glioblastoma/metabolismo , Humanos , Lipossomos/farmacologia , Fenômenos Magnéticos , Piroptose , Espécies Reativas de Oxigênio , Temozolomida/farmacologia , Temozolomida/uso terapêutico , TemperaturaRESUMO
The noninvasive continuous analysis of human sweat is of great significance for improved healthcare diagnostics and treatment in the future, for which a wearable potentiometry-based ion-selective electrode (ISE) has attracted increasing attention, particularly involving ion detection. Note that traditional solid-state ISE electrodes are rigid ion-to-electron transducers that are not conformal to soft human skin and cannot function under stretched states. Here, we demonstrated that vertically aligned mushroom-like gold nanowires (v-AuNW) could serve as stretchable and wearable ion-to-electron transducers for multiplexed, in situ potentiometric analysis of pH, Na+, and K+ in sweat. By modifying v-AuNW electrodes with polyaniline, Na ionophore X, and a valinomycin-based selective membrane, we could specifically detect pH, Na+, and K+, respectively, with high selectivity, reproducibility, and stability. Importantly, the electrochemical performance could be maintained even under 30% strain and during stretch-release cycles without the need of extrinsic structural design. Furthermore, our stretchable v-AuNW ISEs could be seamlessly integrated with a flexible printed circuit board, enabling wireless on-body detection of pH, Na+, and K+ with fast response and negligible cross-talk, indicating considerable promise for noninvasive wearable sweat analysis.
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Técnicas Biossensoriais , Ouro/química , Nanofios/química , Suor/química , Dispositivos Eletrônicos Vestíveis , Eletrodos , Humanos , Concentração de Íons de HidrogênioRESUMO
Essential genes are vitally important to the survival and reproduction of organisms. Many machine learning methods have been widely employed to predict essential genes and have obtained satisfactory results. However, most of these methods are supervised methods and may not obtain the desired result when the labeled data are insufficient. In this paper, we proposed a learning with local and global consistency (LGC) method-based classifier, which was employed to predict the essential genes of 41 prokaryotes. LGC is a graph-based semi-supervised learning method that can construct a prediction model using finite label and constraint information. The performance of the proposed classifier was evaluated by employing intra-organism prediction and leave-one-species-out validation. The average AUC value of 41 organisms in intra-organisms prediction was 0.723 when the labeled sample ratio was 0.5. The results of this study indicate that the proposed method can achieve acceptable prediction performance with limited labeled data. Additionally, the results demonstrate that this method has good universality.
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Genes Essenciais/genética , Células Procarióticas/metabolismo , Aprendizado de Máquina Supervisionado , Área Sob a Curva , Bases de Dados Genéticas , Curva ROCRESUMO
This study aimed to investigate the potential effects of gold nanoparticles (Au-NPs) on rat cortical neurons exposed to oxygen-glucose deprivation/reperfusion (OGD/R) and to elucidate the corresponding mechanisms. Primary rat cortical neurons were exposed to OGD/R, which is commonly used in vitro to mimic ischemic injury, and then treated with 5- or 20-nm Au-NPs. We then evaluated cell viability, apoptosis, oxidative stress, and mitochondrial respiration in these neurons. We found that 20-nm Au-NPs increased cell viability, alleviated neuronal apoptosis and oxidative stress, and improved mitochondrial respiration after OGD/R injury, while opposite effects were observed for 5-nm Au-NPs. In terms of the underlying mechanisms, we found that Au-NPs could regulate Akt signaling. Taken together, these results show that 20-nm Au-NPs can protect primary cortical neurons against OGD/R injury, possibly by decreasing apoptosis and oxidative stress, while activating Akt signaling and mitochondrial pathways. Our results suggest that Au-NPs may be potential therapeutic agents for ischemic stroke.
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Glucose/metabolismo , Ouro/uso terapêutico , Nanopartículas Metálicas/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , Oxigênio/metabolismo , Traumatismo por Reperfusão/tratamento farmacológico , Animais , Antioxidantes/efeitos adversos , Antioxidantes/química , Antioxidantes/uso terapêutico , Apoptose/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Córtex Cerebral/efeitos dos fármacos , Glicogênio Sintase Quinase 3 beta/metabolismo , Ouro/efeitos adversos , Ouro/química , Inflamação/tratamento farmacológico , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Nanopartículas Metálicas/efeitos adversos , Nanopartículas Metálicas/química , Mitocôndrias/efeitos dos fármacos , Neurônios/citologia , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/efeitos adversos , Fármacos Neuroprotetores/química , Estresse Oxidativo/efeitos dos fármacos , Tamanho da Partícula , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacosRESUMO
BACKGROUND: Exosomes are potential markers for several diseases and health problems. Type 1 diabetes (T1D) has increasingly been reported in children and the world T1D has become the main type of diabetes in children. This study aimed to understand the function of urinary exosomal miRNAs in T1D in children. METHODS: We collected urinary samples from 30 healthy controls and 30 T1D in children. All exosomes were isolated with a combined centrifugation and were characterized by electron microscopy and western blot. The small RNA sequence was used to detect the urinary exosomal miRNAs, and miRNA markers were validated by real-time quantitative PCR. Two exosome diagnostic miRNAs were confirmed by receiver operating characteristic analyses. RESULTS: In this study, we found higher urinary exosomal miR-424 and miR-218 expression in T1D in children than in healthy controls. Urinary exosomal miR-424 and miR-218 showed better accuracy for T1D diagnose in children. CONCLUSIONS: Our results suggest that urinary exosomal miR-424 and miR-218 are biomarkers for T1D detection in children; miR-424 and miR-218 may be predictive of T1D prognosis in children.
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Biomarcadores/metabolismo , Diabetes Mellitus Tipo 1/genética , Exossomos/genética , MicroRNAs/genética , Biomarcadores/urina , Criança , Diabetes Mellitus Tipo 1/diagnóstico , Diabetes Mellitus Tipo 1/urina , Exossomos/metabolismo , Exossomos/ultraestrutura , Feminino , Perfilação da Expressão Gênica/métodos , Hemoglobinas Glicadas/análise , Humanos , Masculino , MicroRNAs/urina , Microscopia Eletrônica de Transmissão , Prognóstico , Curva ROC , Análise de Sequência de RNA/métodosRESUMO
PURPOSE: To create a standard Western Chinese normal functional brain database for quantitative analysis using 2-deoxy-2-[18F] fluoro-d-glucose (18F-FDG) positron emission tomography (PET) images and MIMneuro software. METHODS: 78 healthy right-handed Chinese volunteers from Tangdu Hospital were scanned using 18F-FDG PET to evaluate brain metabolism between March and October 2016. All PET images were processed using MIMneuro software to create a normal database platform. The platform included anatomical optimization to facilitate spatial localization of abnormalities and a statistical comparison with normal cases utilizing the Z-scores, which represent the number of standard deviations from the mean of the normal controls in the database. RESULTS: The novel Chinese brain metabolism database platform including 78 healthy volunteers (male: female 40:38; age 3-78 years, mean age, 45 years) was constructed based on the MIMneuro software, which increased the diagnostic confidence in the test patient by quantifying and emphasizing the abnormality. The BrainAlignTM deformation algorithm of MIMneuro matched the size, shape, and orientation of the patient's brain scan to a template brain for comparison against a database of normal controls. The quantitative analysis performed on a voxel and regional level was useful in assessing the areas of abnormalities. CONCLUSIONS: A novel Chinese 18F-FDG PET-based normal brain function database was created to highlight the local regions of abnormal metabolic activity through quantitative comparisons against the normal database. The Z-scores obtained by MIMneuro potentially aid in visualizing and quantifying the subtle lesions on 18FDG-PET scan images as observed in a patient diagnosed with epilepsy.
Assuntos
Encéfalo/diagnóstico por imagem , Bases de Dados Factuais , Epilepsia/diagnóstico por imagem , Fluordesoxiglucose F18 , Processamento de Imagem Assistida por Computador , Tomografia por Emissão de Pósitrons , Adolescente , Adulto , Idoso , Encéfalo/metabolismo , Criança , Pré-Escolar , China , Bases de Dados Factuais/estatística & dados numéricos , Epilepsia/metabolismo , Feminino , Humanos , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Imagem Multimodal , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/estatística & dados numéricos , Tomografia por Emissão de Pósitrons/estatística & dados numéricos , Adulto JovemRESUMO
Lateral flow assay strips (LFASs) with Au nanoparticles (NPs) have been widely used as a probe for biomarkers in point-of-care testing; however, there still remain challenges in detection sensitivity and quantitative analysis. In this study, we developed a surface-enhanced Raman scattering (SERS)-based LFAS for quantitative analysis of a biomarker in the low concentration range. Moreover, apart from conventional Au NPs, three other types of citrate-capped Au-Ag bimetallic NPs: Au core with Ag shell NPs (Au@Ag NPs), rattle-like Au core in Ag-Au shell NPs (Au@Ag-Au NPs) and Ag-Au NPs were prepared and functionalized, and their solution-based SERS activities were comprehensively studied by experimental measurement and theoretical analysis. The results clearly indicated that the citrate-capped Au@Ag-Au NPs exhibited the highest SERS activity among the probes tested. Au@Ag-Au NPs were used as both optical and SERS probes in a SERS-based LFAS. In the presence of the analyte at high concentrations, a purple color appeared in the test zone. Highly sensitive and quantitative analysis was realized by measurement of SERS signals from the test lines. One of the most specific markers for cardiac injury, cardiac troponin I (cTnI), was chosen as the detection model. The detection limit of the SERS-based LFAS for cardiac troponin I was 0.09 ng/mL, lowered by nearly 50 times compared with visual results, and could be further lowered by optimization. These results demonstrated that the SERS-based LFAS using citrate-capped Au@Ag-Au NPs as probes can be a powerful tool for highly sensitive and quantitative detection of biomarkers. Graphical abstract A surface-enhanced Raman scattering (SERS)-based lateral flow assay strip using rattle-like Au core in Ag-Au shell (Au@Ag-Au) nanoparticles as probes was developed for quantitative analysis of a biomarker, with a detection limit nearly 50 times lower than that of visual assessment. C control line, T test line.
Assuntos
Ouro/química , Nanopartículas Metálicas/química , Fitas Reagentes/análise , Prata/química , Análise Espectral Raman/instrumentação , Troponina I/sangue , Anticorpos Imobilizados/química , Desenho de Equipamento , Humanos , Limite de Detecção , Nanopartículas Metálicas/ultraestrutura , Testes Imediatos , Análise Espectral Raman/métodosRESUMO
BACKGROUND: Methamphetamine (METH) is a psychostimulant with high abuse liability that affects the monoamine neurotransmitter systems, particularly the dopamine system. Currently there are no effective medications for the treatment of METH abuse to restore METH-induced dopaminergic dysfunction. The Jitai tablet (JTT), a commercial traditional Chinese medicinal preparation, has been shown to modulate the dopaminergic function both in heroin addicts and in morphine-dependent rats. The purpose of this study was to investigate, in a rodent model, whether JTT can protect against METH-induced neurotoxicity, and/or restore METH-damaged dopaminergic function. METHODS: Immunohistochemical staining and/or autoradiography staining were used to detect tyrosine hydroxylase (TH) expression in the substantia nigra, and to examine the levels of dopamine transporter (DAT), dopamine D2 receptor (D2R) and TH levels in the striatum. Using a stereotyped behavior rating scale, we evaluated the inhibitory effect of JTT on METH-induced behavioral sensitization. RESULTS: Repeated METH administration induced obvious stereotyped behavior and neurotoxicity on the dopaminergic system. Pre-treatment with JTT significantly attenuated METH-induced stereotyped responses, and interdicted METH-induced changes in the levels of DAT, D2R and TH expression. Treatment with JTT after METH administration restored DAT, D2R and TH expression to normal levels. CONCLUSIONS: Our results indicated that JTT protects against METH-induced neurotoxicity and restores the dopaminergic function, and thus might be a potential treatment for the dopaminergic deficits associated with METH abuse.
Assuntos
Dopamina/metabolismo , Medicamentos de Ervas Chinesas/administração & dosagem , Metanfetamina/toxicidade , Fármacos Neuroprotetores/administração & dosagem , Síndromes Neurotóxicas/tratamento farmacológico , Animais , Comportamento Animal/efeitos dos fármacos , Humanos , Masculino , Medicina Tradicional Chinesa , Síndromes Neurotóxicas/genética , Síndromes Neurotóxicas/metabolismo , Síndromes Neurotóxicas/psicologia , Ratos , Ratos Wistar , Receptores de Dopamina D2/genética , Receptores de Dopamina D2/metabolismo , Substância Negra/efeitos dos fármacos , Substância Negra/enzimologia , Comprimidos/administração & dosagem , Tirosina 3-Mono-Oxigenase/genética , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
Thermal decomposition, as the main synthetic procedure for the synthesis of magnetic nanoparticles (NPs), is facing several problems, such as high reaction temperatures and time consumption. An improved a microwave-assisted thermal decomposition procedure has been developed by which monodisperse Fe3 O4 NPs could be rapidly produced at a low aging temperature with high yield (90.1 %). The as-synthesized NPs show excellent inductive heating and MRI properties in vitro. In contrast, Fe3 O4 NPs synthesized by classical thermal decomposition were obtained in very low yield (20.3 %) with an overall poor quality. It was found for the first time that, besides precursors and solvents, magnetic NPs themselves could be heated by microwave irradiation during the synthetic process. These findings were demonstrated by a series of microwave-heating experiments, Raman spectroscopy and vector-network analysis, indicating that the initially formed magnetic Fe3 O4 particles were able to transform microwave energy into heat directly and, thus, contribute to the nanoparticle growth.
RESUMO
Sum frequency generation (SFG) vibrational spectroscopy has been widely employed to investigate molecular structures of biological surfaces and interfaces including model cell membranes. A variety of lipid monolayers or bilayers serving as model cell membranes and their interactions with many different molecules have been extensively studied using SFG. Here, we conducted an in-depth investigation on polarization-dependent SFG signals collected from interfacial lipid monolayers using different experimental geometries, i.e., the prism geometry (total internal reflection) and the window geometry (external reflection). The different SFG spectral features of interfacial lipid monolayers detected using different experimental geometries are due to the interplay between the varied Fresnel coefficients and second-order nonlinear susceptibility tensor terms of different vibrational modes (i.e., ss and as modes of methyl groups), which were analyzed in detail in this study. Therefore, understanding the interplay between the interfacial Fresnel coefficients and χ((2)) tensors is a prerequisite for correctly understanding the SFG spectral features with respect to different experimental geometries. More importantly, the derived information in this paper should not be limited to the methyl groups with a C3v symmetry; valid extension to interfacial functional groups with different molecular symmetries and even chiral interfaces could be expected.
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The latest social VR technologies have enabled users to attend traditional media and arts performances together while being geographically removed, making such experiences accessible despite budget, distance, and other restrictions. In this work, we aim at improving the way remote performances are shared by designing and evaluating a VR theatre lobby which serves as a space for users to gather, interact, and relive the common experience of watching a virtual opera. We conducted an initial test with experts ($\mathrm{N}=10$, i.e., designers and opera enthusiasts) in pairs using our VR lobby prototype, developed based on the theoretical lobby design concept. A unique aspect of our experience is its highly realistic representation of users in the virtual space. The test results guided refinements to the VR lobby structure and implementation, aiming to improve the user experience and align it more closely with the social VR lobby's intended purpose. With the enhanced prototype, we ran a between-subject controlled study ($\mathrm{N}=40$) to compare the user experience in the social VR lobby between individuals and paired participants. To do so, we designed and validated a questionnaire to measure the user experience in the VR lobby. Results of our mixed-methods analysis, including interviews, questionnaire results, and user behavior, reveal the strength of our social VR lobby in connecting with other users, consuming the opera in a deeper manner, and exploring new possibilities beyond what is common in real life. All supplemental materials are available at https://github.com/cwi-dis/IEEEVR2024-VRLobby.
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Individuals with opioid use disorder (OUD) have been reported to show abnormal brain metabolism and impaired coupling among brain networks such as the default mode network (DMN), salience network (SN), and executive control network (ECN). However, the characteristics of brain glucose metabolism and its related functions in the brain networks in individuals with OUD remain unknown. Thirty-six individuals with OUD and thirty matched healthy controls (HCs) were recruited in this integrated positron emission tomography/magnetic resonance imaging (PET/MRI) study. Differences in glucose metabolism were analyzed by using 18F-fluorodeoxyglucose (18F-FDG), and the corresponding coupling characteristics of the individuals with OUD were also analyzed. The individuals with OUD showed widespread bilateral hypometabolism in the middle temporal gyrus (MTG), superior temporal gyrus, angular gyrus, supramarginal gyrus, inferior parietal lobe, Rolandic operculum, and left insula, but obvious hypermetabolism in the brainstem and left cerebellum. Meanwhile, in individuals with OUD, the hypometabolism of right MTG which is included in the DMN was accompanied by decreased coupling with the left superior frontal gyrus and right superior parietal gyrus which are included in the ECN. Furthermore, individuals with OUD showed a positive correlation between the duration of heroin use and glucose metabolism of the left MTG. The individuals with OUD were characterized by widespread bilateral hypometabolism in the temporal and parietal regions but obvious hypermetabolism in the brainstem and left cerebellum. The results suggest that the hypometabolism in the temporal and parietal regions might be related to DMN dysfunction and the hypermetabolism in the brainstem and left cerebellum may be compensate for other brain regions showing hypometabolism. In particular, hypometabolism in the self-referential-related DMN regions in OUD might attenuate their relationships with the inhibitory-control-related ECN regions. These findings highlight the importance of evaluating the metabolic and functional profiles of the right MTG in future studies on the treatment of OUD.
Assuntos
Imageamento por Ressonância Magnética , Transtornos Relacionados ao Uso de Opioides , Humanos , Encéfalo/metabolismo , Tomografia por Emissão de Pósitrons , Glucose/metabolismo , Transtornos Relacionados ao Uso de Opioides/diagnóstico por imagemRESUMO
The rapid and sensitive detection of pathogenic viruses is important for controlling pandemics. Herein, a rapid, ultrasensitive, optical biosensing scheme was developed to detect avian influenza virus H9N2 using a genetically engineered filamentous M13 phage probe. The M13 phage was genetically engineered to bear an H9N2-binding peptide (H9N2BP) at the tip and a gold nanoparticle (AuNP)-binding peptide (AuBP) on the sidewall to form an engineered phage nanofiber, M13@H9N2BP@AuBP. Simulated modelling showed that M13@H9N2BP@AuBP enabled a 40-fold enhancement of the electric field enhancement in surface plasmon resonance (SPR) compared to conventional AuNPs. Experimentally, this signal enhancement scheme was employed for detecting H9N2 particles with a sensitivity down to 6.3 copies/mL (1.04 × 10-5 fM). The phage-based SPR scheme can detect H9N2 viruses in real allantoic samples within 10 min, even at very low concentrations beyond the detection limit of quantitative polymerase chain reaction (qPCR). Moreover, after capturing the H9N2 viruses on the sensor chip, the H9N2-binding phage nanofibers can be quantitatively converted into plaques that are visible to the naked eye for further quantification, thereby allowing us to enumerate the H9N2 virus particles through a second mode to cross-validate the SPR results. This novel phage-based biosensing strategy can be employed to detect other pathogens because the H9N2-binding peptides can be easily switched with other pathogen-binding peptides using phage display technology.
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Bacteriófagos , Técnicas Biossensoriais , Vírus da Influenza A Subtipo H9N2 , Influenza Aviária , Nanopartículas Metálicas , Nanofibras , Animais , Ouro , Influenza Aviária/diagnóstico , PeptídeosRESUMO
Gold nanoshells currently attract increasing research interests due to the important role in many subjects. For practical applications, random arrangement of the nanoparticles is often unfavored so that the assembly of gold nanoshells is becoming a central issue. We here proposed to utilize time-variant magnetic field to direct the assembly of gold nanoshells. It was discovered that the alternating magnetic field can mediate the vortex-like assembly of gold nanoshells. The mechanism was explored and thought to be relative with the electric field of induction which caused the thermal gradient on the substrate and the electric force. The vortexlike structure as well as the assembly mechanism will play an important role in research and application of gold nanomaterials.
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Ouro/química , Nanoconchas/química , Campos Magnéticos , Tamanho da Partícula , Propriedades de SuperfícieRESUMO
Based on the study of apoptosis-induced and anti-proliferation behavior of silver nanoparticles (AgNPs) on cancer cells, the attractively therapeutic effect and potential application of AgNPs in anti-cancer field was gradually revealed. Here we investigated the effect of 10 nm silver nanoparticles (AgNPs) on human glioma U251 cells upon the combination treatment of ionizing radiation (IR) treatment with magnetic hyperthermia (MHT). AgNPs showed both radio and thermo sensitivity on U251 cells from the surviving fraction curve. Besides, we found both X-rays and heat could enhance the content of cells uptake of AgNPs. As the amount of intracellular AgNPs accumulated, the apoptosis rate of U251 cells enhanced. Furthermore, we established a simplified model for calculating cell survival rate and demonstrated that after RT, MHT and RT combined with MHT, AgNPs could significantly inhibited cancer cell proliferation. Our results revealed that AgNPs could have a potential application in enhancing effect of RT with MHT combination therapy induced killing of cancer cells.
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Glioma/patologia , Glioma/terapia , Hipertermia Induzida/métodos , Magnetoterapia/métodos , Nanopartículas Metálicas/uso terapêutico , Nanocápsulas/administração & dosagem , Radioterapia Conformacional/métodos , Prata/uso terapêutico , Linhagem Celular Tumoral , Terapia Combinada , HumanosRESUMO
Achieving metal nanoparticles with high peroxidase activity and visible-light plasmonic property for lateral flow immunoassay has attracted extensive attention in the industry. However, the major challenge lies in establishing a general and robust preparation strategy. In this contribution, we developed a citrate-capped trimetallic Au@Ag-Pt nanorattle by employing seed-mediated growth and galvanic replacement reaction under a convenient condition, which can be translated directly to industrialized production. The rattle-like architecture empowers the Au@Ag-Pt NPs peroxidase-like activity while retaining the plasmonic property with intense color in the visible-light range. According to testing requirements, Au@Ag-Pt NPs-LFIA provides two colorimetric modes: low-sensitivity mode based on the color from their intrinsic plasmonic property and the high-sensitivity mode based on the nanozyme-triggered chromogenic reaction. Human cardiac troponin I (cTnI), one of the most specific markers for cardiac injury, was chosen as the detection model. Mainly, ultrasensitive colorimetric detection of human cTnI was successfully achieved as low as â¼20 pg mL-1. This strategy is robust to guarantee the stability and repeatability of the peroxidase activity without exact control, which can directly dock with the industrialized production of traditional LFIA strips and be readily adapted for on-demand clinical diagnosis.
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Técnicas Biossensoriais , Nanopartículas Metálicas , Colorimetria , Ouro , Humanos , Imunoensaio , Limite de Detecção , Peroxidases , Troponina IRESUMO
Pancreatic cancer has led to an extremely high mortality rate because of its insidious onset and lack of early clinical symptoms. Effective early diagnosis is essential to improve the treatment of pancreatic cancer. Tumor-secreted extracellular vesicles (EVs) have attracted great interest as potential tumor biomarkers. However, most of the methods for detecting serum EVs have some general problems such as cumbersome, time-consuming extraction steps, and high cost, which limit greatly the research on cancer detection based on EVs. Herein, we report a light-initiated chemiluminescent assay (LICA) method using photosensitive beads for direct detection of EVs in serum enriched with ephrin type-A receptor 2 (EphA2), which show high expression in pancreatic cancer patients. Combining with a serum biomarker CA19-9, pancreatic cancer patients could be distinguished rapidly by sensitive detection of EphA2-EVs from serum without any purification. This developed method could be extended to improve the diagnosis efficiency for other cancers and gain an insight into EV detection.