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DNA walker, a type of dynamic DNA device that is capable of moving progressively along prescribed walking tracks, has emerged as an ideal and powerful tool for biosensing and bioimaging. However, most of the reported three-dimensional (3D) DNA walker were merely designed for the detection of a single target, and they were not capable of achieving universal applicability. Herein, we reported for the first time the development of a proximity-induced 3D bipedal DNA walker for imaging of low abundance biomolecules. As a proof of concept, miRNA-34a, a biomarker of breast cancer, is chosen as the model system to demonstrate this approach. In our design, the 3D bipedal DNA walker can be generated only by the specific recognition of two proximity probes for miRNA-34a. Meanwhile, it stochastically and autonomously traveled on 3D tracks (gold nanoparticles) via catalytic hairpin assembly (CHA), resulting in the amplified fluorescence signal. In comparison with some conventional DNA walkers that were utilized for living cell imaging, the 3D DNA walkers induced by proximity ligation assay can greatly improve and ensure the high selectivity of bioanalysis. By taking advantage of these unique features, the proximity-induced 3D bipedal DNA walker successfully realizes accurate and effective monitoring of target miRNA-34a expression levels in living cells, affording a universal, valuable, and promising platform for low-abundance cancer biomarker detection and accurate identification of cancer.
Assuntos
Ouro , MicroRNAs , MicroRNAs/análise , MicroRNAs/metabolismo , Humanos , Ouro/química , DNA/química , Nanopartículas Metálicas/química , Técnicas BiossensoriaisRESUMO
Biological imaging-guided targeted tumor therapy has been a soughtafter goal in the field of cancer diagnosis and treatment. To this end, we proposed a strategy to modulate surface plasmon resonance and endow WO3-x nanoparticles (NPs) with enzyme-like catalytic properties by doping Fe2+ in the structure of the NPs. Doping of the Fe2+ introduced oxygen vacancies into the structure of the NPs, inducing a red shift of the maximum absorption wavelength into the near-infrared II (NIR-II) region and enhancing the photoacoustic (PA) and photothermal properties of the NPs for more effective imaging-guided cancer therapy. Under NIR-II laser irradiation, the Fe-WO3-x NPs produced very strong NIR-II PA and photothermal effects, which significantly enhanced the PA imaging and photothermal treatment effects. On the other hand, Fe2+ in Fe-WO3-x could undergo Fenton reactions with H2O2 in the tumor tissue to generate ·OH for chemodynamic therapy. In addition, Fe-WO3-x can also catalyze the above reactions to produce more reactive oxygen species (ROS) and induce the oxidation of NADH to interfere with intracellular adenosine triphosphate (ATP) synthesis, thereby further improving the efficiency of cancer therapy. Specific imaging of tumor tissue and targeted synergistic therapy was achieved after ligation of a MUC1 aptamer to the surface of the Fe-WO3-x NPs by the complexing of -COOH in MUC1 with tungsten ions on the surface of the NPs. These results demonstrated that Fe-WO3-x NPs could be a promising diagnosis and therapeutic agent for cancer. Such a study opens up new avenues into the rational design of nanodiagnosis and treatment agents for NIR-II PA imaging and cancer therapy.
Assuntos
Técnicas Fotoacústicas , Ressonância de Plasmônio de Superfície , Tungstênio , Animais , Humanos , Camundongos , Tungstênio/química , Raios Infravermelhos , Óxidos/química , Neoplasias/diagnóstico por imagem , Neoplasias/terapia , Neoplasias/tratamento farmacológico , Nanopartículas/química , Nanopartículas/uso terapêutico , Linhagem Celular Tumoral , Espécies Reativas de Oxigênio/metabolismoRESUMO
Smart theranostic nanoprobes with the integration of multiple therapeutic modalities are preferred for precise diagnosis and efficient therapy of tumors. However, it remains a big challenge to arrange the imaging and two or more kinds of therapeutic agents without weakening the intended performances. In addition, most existing fluorescence (FL) imaging agents suffer from low spatiotemporal resolution due to the short emission wavelength (<900 nm). Here, novel three-in-one Ag2S quantum dot (QD)-based smart theranostic nanoprobes were proposed for in situ ratiometric NIR-II FL imaging-guided ion/gas combination therapy of tumors. Under the acidic tumor microenvironment, three-in-one Ag2S QDs underwent destructive degradation, generating toxic Ag+ and H2S. Meanwhile, their FL emission at 1270 nm was weakened. Upon introduction of a downconversion nanoparticle (DCNP) as the delivery carrier and NIR-II FL reference signal unit, the formed Ag2S QD-based theranostic nanoprobes could achieve precise diagnosis of tumors through ratiometric NIR-II FL signals. Also, the generated Ag+ and H2S enabled specific ion/gas combination therapy toward tumors. By combining the imaging and therapeutic functions, three-in-one Ag2S QDs may open a simple yet reliable avenue to design theranostic nanoprobes.
Assuntos
Imagem Óptica , Pontos Quânticos , Compostos de Prata , Pontos Quânticos/química , Compostos de Prata/química , Humanos , Animais , Camundongos , Raios Infravermelhos , Nanomedicina Teranóstica , Sulfeto de Hidrogênio/análise , Sulfeto de Hidrogênio/química , Concentração de Íons de HidrogênioRESUMO
A disease-targeting nanoplatform that integrates imaging with therapeutic activity would facilitate early diagnosis, treatment, and therapeutic monitoring. To this end, a macrophage membrane-coated Cu-WO3-x-Hydro820 (CWHM) nanoreactor was prepared. This reactor was shown to target inflammatory tissues. The reactive oxygen species (ROS) such as H2O2 and ·OH in inflammatory tissues can react with Hydro820 in the reactor to form the NIR fluorophore IR820. This process allowed photoacoustic/fluorescence dual-mode imaging of H2O2 and ·OH, and it is expected to permit visual diagnosis of inflammatory diseases. The Cu-WO3-x nanoparticles within the nanoreactor shown catalase and superoxide enzyme mimetic activity, allowing the nanoreactor to catalyze the decomposition of H2O2 and ·O2- in inflammatory cells of hepatic tissues in a mouse model of liver injury, thus alleviating the oxidative stress of damaged liver tissue. This nanoreactor illustrates a new strategy for the diagnosis and treatment of hepatitis and inflammatory liver injury.
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The sensing sensitivity was improved for silver nanoparticles (AgNPs)-based colorimetric biosensors by using the most suitable salt to induce AgNPs aggregation. As for the salt composed of low-affinity anion and monovalent cation, the cation-dependent charge screening effect was the driving force for AgNPs aggregation. Apart from the charge screening effect, both the bridging of multivalent cation to the surface ligand of AgNP and the interaction between anion and Ag contributed to inducing AgNPs aggregation. Considering the higher aggregation efficiency of AgNPs resulted in a narrower sensing range, salt composed of low-affinity anion and monovalent cation was recommended for AgNPs-based colorimetric analysis, which was confirmed by fourfold higher sensitivity of DNA-21 detection using NaF than NaCl. This work inspires further thinking on improving the sensing performance of metal nanomaterials-based sensors from the point of colloidal surface science.
Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Cloreto de Sódio , Prata , Colorimetria/métodos , Ânions , Cátions MonovalentesRESUMO
Most nanozyme-based electrochemical sensing strategies depend on the catalytic formation of electroactive substances, while the electrochemical properties of nanozymes have rarely been explored. In this study, magnetic nanoparticles encapsulated metal-organic framework served as precursors to prepare bioinspired nanozymes with both laccase-mimicking activity and electroactivity. Owing to the strong affinity between thiram (THR) and Cu(II) active sites in the nanozymes, the binding of THR inhibited nanozyme catalytic activity toward catechol (CT) oxidation and enhanced nanozyme conductivity. A lower oxidation current (ICT) of CT was accompanied by a higher oxidation signal (ICu) of Cu(II), allowing a ratiometric electrochemical response of the electroactive nanozymes toward the incoming THR. The signal ratio (ICu/ICT) displayed a good linear relationship over a THR concentration range of 10.0 nM-3.0 µM with a limit of detection of 0.15 nM, and the entire THR detection process was rapidly accomplished within 5 min. The high sensitivity and selectivity of the developed electrochemical strategy guaranteed the reliable detection of THR in fruit, vegetable, and river water samples. This study provides new insights into the development of nanozymes for electrochemical analysis.
Assuntos
Lacase , Nanopartículas , Tiram , Oxirredução , CatáliseRESUMO
Cellular trace proteins are critical for maintaining normal cell functions, with their quantitative analysis in individual cells aiding our understanding of the role of cell proteins in biological processes. This study proposes a strategy for the quantitative analysis of alpha-fetoprotein in single cells, utilizing a lysosome microenvironment initiation and a DNAzyme-assisted intracellular signal amplification technique based on electrophoretic separation. A nanoprobe targeting lysosomes was prepared, facilitating the intracellular signal amplification of alpha-fetoprotein. Following intracellular signal amplification, the levels of alpha-fetoprotein (AFP) in 20 HepG2 hepatoma cells and 20 normal HL-7702 hepatocytes were individually evaluated using microchip electrophoresis with laser-induced fluorescence detection (MCE-LIF). Results demonstrated overexpression of alpha-fetoprotein in hepatocellular carcinoma cells. This strategy represents a novel technique for single-cell protein analysis and holds significant potential as a powerful tool for such analyses.
Assuntos
Carcinoma Hepatocelular , DNA Catalítico , Eletroforese em Microchip , Neoplasias Hepáticas , Humanos , alfa-Fetoproteínas/análise , Eletroforese em Microchip/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Lisossomos/química , Carcinoma Hepatocelular/patologia , Microambiente TumoralRESUMO
By integrating near-infrared (NIR) light-dependent optical control and DNA walkers-based signal amplification, upconversion luminescence-activated DNA nanomachines hold great potential in conducting an in vivo analysis. For the typical DNA nanomachines, the immobile multivalent recognition interface greatly compromised the reaction kinetics and amplification efficiency due to the cleavage-dependent response mode. In this work, novel upconversion luminescence-activated DNA nanomachines with a fluid multivalent recognition interface were reported for rapid and sensitive in vivo imaging. As a proof-of-concept study, the photolocked DNAzyme-based walker system was anchored on the surface of phospholipid membrane-coated upconversion nanoparticles through the cholesterol-phospholipid interaction to acquire a fluid multivalent recognition interface. Upon sequential inputs of NIR light and metal ions, the formed DNA nanomachines were autonomously initiated and generated a cascade of amplified signal. Relative to the typical DNA nanomachines, the proposed ones possess an accelerated reaction rate and an improved amplification capability owing to a higher local concentration by the lateral mobility. The present work provides a versatile alternative for performing precise and highly efficient in vivo analysis.
Assuntos
Luminescência , Nanopartículas , Diagnóstico por Imagem , DNA , FosfolipídeosRESUMO
A novel biodegradable layered double hydroxide-copper selenide nanocomplex was prepared by anchoring copper selenide on manganese iron layered double hydroxide nanosheets. This nanocomplex can specifically release CuSe, Mn2+ and Fe3+ in the tumor microenvironment, which implements NIR-II photoacoustic imaging-guided synergistic cancer therapy under 1064 nm laser irradiation.
Assuntos
Neoplasias , Técnicas Fotoacústicas , Humanos , Manganês , Cobre , Neoplasias/diagnóstico por imagem , Neoplasias/tratamento farmacológico , Hidróxidos , Ferro , Microambiente TumoralRESUMO
The simultaneous quantification of multiple microRNAs (miRNA) in a single cell can help scientists understand the relationship between different miRNA groups and different types of cancers from an miRNA omics perspective at the single-cell level. However, there currently remains a challenge in developing techniques for the simultaneous absolute quantification of multiple miRNAs in single cells. Herein, we propose a framework nucleic acid (FNA)-mediated multimodal tandem multivariate signal amplification strategy for simultaneous absolute quantification of three different miRNAs in a single cell. In this study, DNA hexahedron FNAs (DHFs) and DNA tetrahedron FNAs (DTFs) were first prepared, multiple DNA hairpins and substrates were then connected to the hexahedron frame nucleic acid as the target recognition units, and three substrates with labeled FAM fluorophores on the tetrahedral frame nucleic acid served as signal output units. After the two types of FNAs entered the cell, they reacted with three different miRNAs (miRNA-155, miRNA-373, and miRNA-21) and multimodal tandem multivariate signal amplification was initiated simultaneously, reducing the detection limit of the three miRNAs to 8 × 10-15, 2 × 10-15, and 1 × 10-15 M, respectively. The detection sensitivity of the three miRNAs was simultaneously increased by six orders of magnitude, reaching the quantitative requirement of trace miRNAs in single cells. Combined with single-cell injection, membrane melting, and intracellular component separation technology on a microchip electrophoresis platform, we achieved the simultaneous absolute quantification of three different miRNAs in a single cell, thereby providing an important novel method that can be used to conduct single-cell research.
Assuntos
MicroRNAs , Ácidos Nucleicos , MicroRNAs/análise , DNA/genética , Corantes Fluorescentes , Técnicas de Amplificação de Ácido Nucleico/métodosRESUMO
Upconversion nanoparticles enable indirect activation of photodynamic therapy (PDT) using near-infrared (NIR) light, providing an excellent alternative for treating deep tumors. However, conventional NIR light-triggered PDT systems suffered from low spatiotemporal accuracy and restricted therapeutic efficiency in vivo. In this work, DNA logic circuits were functionally modified on down/upconversion nanoparticles (D/UCNPs) to construct smart down/upconversion nanomachines (D/UCNMs) for NIR light-triggered PDT toward target tumors. Upon dual inputs of tumor-associated GSH and TK1 mRNA, DNA logic circuits perform "AND" logic computation and initiate the toehold-mediated strand displacement reaction. Meanwhile, the quenched upconversion fluorescence was recovered and then the approaching photosensitizers were activated, leading to in situ output of singlet oxygen (1O2) for precise and enhanced PDT. Importantly, the biodistribution of the D/UCNMs in vivo could be visualized by second near-infrared (NIR-II) fluorescence imaging via the downconversion luminance of D/UCNPs, which further contributed to performing precise PDT. This work provides new insights into the development of precise and highly efficient PDT systems.
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A typical colorimetric sandwich-type sensor relies on dual antibodies/aptamers to specifically visualize the targets. The requirement of dual antibodies/aptamers and low signal intensity inevitably increases the design difficulty and compromises the sensing sensitivity. In this work, a novel sandwich-type aptasensor was developed using single aptamer-functionalized magnetic nanoparticles as a specific recognition unit to target cancer cells and a bimetallic metal-organic frameworks (MOFs)-based nanozymes as a colorimetric signal amplification unit. The well-defined crystalline structure of UIO-66 MOFs enabled the introduction of Fe/Zr bimetal nodes, which possessed integrated properties of the peroxidase-like nanozyme activity and direct coordinately binding to the cell surface. Such a novel construction strategy of sandwich-type aptasensors achieved simple, sensitive, and specific detection of the target cancer cells, which will inspire the development of biosensors.
Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Nanopartículas Metálicas , Estruturas Metalorgânicas , Nanopartículas , Neoplasias , Estruturas Metalorgânicas/química , Colorimetria , Aptâmeros de Nucleotídeos/química , Nanopartículas Metálicas/química , Limite de Detecção , Neoplasias/diagnósticoRESUMO
Fluorescence-assisted digital counting analysis allowed sensitive quantification of targets by measuring individual fluorescent labels. However, traditional fluorescent labels suffered from low brightness, small size, and sophisticated preparation procedures. Herein, engineering fluorescent dye-stained cancer cells with magnetic nanoparticles were proposed to construct single-cell probes for fluorescence-assisted digital counting analysis by quantifying the target-dependent binding or cleaving events. Various engineering strategies of cancer cells including biological recognition and chemical modification were developed for rationally designing single-cell probes. Introduction of suitable recognition elements into single-cell probes allowed digital quantification of each target-dependent event via counting the colored single-cell probes in the representative image taken using a confocal microscope. The reliability of the proposed digital counting strategy was corroborated by traditional optical microscopy- and flow cytometry-dependent counting technologies. The advantages of single-cell probes, including high brightness, big size, ease of preparation, and magnetic separation, contributed to the sensitive and selective analysis of targets of interest. As proof-to-concept assays, indirect analysis of exonuclease III (Exo III) activity, as well as direct quantitation of cancer cells, were investigated, and the potential in biological sample analysis was also assessed. This sensing strategy will open a new avenue for the development of biosensors.
Assuntos
Técnicas Biossensoriais , Nanopartículas , Neoplasias , Reprodutibilidade dos Testes , Espectrometria de Fluorescência , Técnicas Biossensoriais/métodos , Corantes Fluorescentes/metabolismo , Sondas de DNARESUMO
Tumor microenvironment-mediated ratiometric second near-infrared (NIR-II) fluorescence imaging and photodynamic therapy contribute to accurate diagnosis and highly efficient therapy of deep tumors. However, it is challenging to integrate these functions into one nanodrug due to the difficulty in preparing triple-emission nanoprobes. In this work, single-excitation triple-emission (wavelength at 660, 1060, and 1550 nm) down-/up-conversion nanoassemblies were prepared by conjugating dual-ligands-stabilized gold nanoclusters (cgAuNCs) into down-/up-conversion nanoparticles (D/UCNPs), which simultaneously realized ratiometric NIR-II fluorescence imaging and chemo-/photodynamic combination therapy toward tumors upon exposure to an 808 nm laser. The presence of dual ligands endowed cgAuNCs with an enhanced NIR-II fluorescence response to endogenous glutathione, allowing in situ ratiometric NIR-II fluorescence imaging of tumors using the prepared nanoassemblies. Additionally, the stabilizing ligand cyclodextrin of cgAuNCs facilitated the loading of the antitumor drug doxorubicin, and D/UCNPs could be modified with the photosensitizer methylene blue. Such a spatially separated functionalization method enabled chemo-/photodynamic combination therapy. This study provides new insights into the design of multifunctional nanoplatforms for tumor diagnosis and treatment.
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Nanopartículas , Neoplasias , Fotoquimioterapia , Humanos , Microambiente Tumoral , Ligantes , Fotoquimioterapia/métodos , Neoplasias/diagnóstico por imagem , Neoplasias/tratamento farmacológico , Imagem Óptica/métodosRESUMO
Our previous study described the mechanism of goose fatty liver formation from cell culture and transcriptome. However, how lipidome of goose liver response to overfeeding is unclear. In this study, we used the same batch of geese (control group and corn flour overfeeding group) to explore the lipidome changes and underlying metabolic mechanisms of goose fatty liver formation. Liquid chromatography-mass spectrometry (LC-MS) was provided to lipidome detection. Liver lipidomics profiles analysis was performed by principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA) and orthogonal partial least squares-discriminant analysis (OPLS-DA), different lipids were identified and annotated, and the enriched metabolic pathways were showed. The results of PCA, PLS-DA, and OPLS-DA displayed a clear separation and discrimination between control group and corn flour overfeeding group. Two hundred and fifty-one different lipids were yielded, which were involved in triglyceride (TG), diglyceride (DG), phosphatidic acids (PA), phosphatidylinositols (PI), phosphatidylethanolamines (PE), phosphatidylcholines (PC), lyso-phosphatidylcholines (LPC), monogalactosylmonoacylglycerol (MGMG), sphingolipids (SM), ceramides (Cer), and hexaglycosylceramides (Hex1Cer). Different lipids were enriched in glycerophospholipid metabolism, glycerolipid metabolism, phosphatidylinositol signaling system, inositol phosphate metabolism, glycosylphosphatidylinositol (GPI)-anchor biosynthesis and sphingolipid metabolism. In conclusion, this is the first report describing the goose fatty liver formation from lipidomics, this study might provide some insights into the underlying glucolipid metabolism disorders in the process of fatty liver formation.
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Fígado Gorduroso , Gansos , Animais , Gansos/metabolismo , Lipidômica , Galinhas/metabolismo , Fígado Gorduroso/veterinária , Fígado Gorduroso/metabolismo , Triglicerídeos/metabolismo , FosfatidilcolinasRESUMO
Slow intermolecular collisions and "always active" responses compromise the amplification efficiency and response accuracy of nonenzymatic hybridization chain reaction (HCR). In this study, a photoactivatable membrane-oriented HCR (MOHCR) system was rationally designed by binding a photocleavable initiator probe onto a target protein and then anchoring cholesterol-modified hairpin-structure fuel probes. When irradiated, the bound initiator probe was photoactivated and initiated self-assembly to generate activatable and amplified imaging. In a proof-of-concept assay, breast-cancer-derived exosomes were imaged based on the surface protein epithelial cell adhesion molecule (EpCAM). Photoactivatable responses provided precise spatiotemporal control of the MOHCR, and fluidic membranes enabled accelerated reaction kinetics. Our MOHCR system demonstrated high efficiency and accuracy in differentiating between plasma samples from breast cancer patients and healthy donors.
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Técnicas Biossensoriais , Exossomos , Neoplasias , Humanos , Exossomos/química , Cinética , Hibridização de Ácido Nucleico , Proteínas/análise , Técnicas Biossensoriais/métodosRESUMO
Elucidating the mechanism and estimating the extent of conformation change of double-stranded DNA (dsDNA) upon ultraviolet (UV) exposure are of vital importance for understanding the DNA photodamage process. The existing research was mainly focused on the lesions of single-stranded DNA (ssDNA) and involved off-site measurement of the photodamage level. In this work, short-wavelength UV (UVC) (254 nm) irradiation was demonstrated to induce the dehybridization of dsDNA due to the loss of paring capacity of photodamaged pyrimidine nucleobases. The intrinsic programmability of dsDNA enabled researchers to rationally design the on-demand dehybridization sites. The spatial conformation switch of dsDNA caused by UVC irradiation could be evolved into a label-free sensing platform for the on-site measurement of the DNA photodamage level.
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Oligonucleotídeos , Raios Ultravioleta , DNA de Cadeia Simples , DNA/genética , Dano ao DNARESUMO
Previous research in our lab showed that 10% glucose, 10% fructose, and 10% sucrose can induce lipid deposition in goose fatty liver formation process more efficiently. However, whether the overfeeding diet supplement with sugar can affect the meat quality is unclear. The aim of this research was to estimate the meat quality of geese overfed with overfeeding diet adding with different types of sugar. The results indicated there were no significant differences in the diameter of muscle fiber, the muscle fiber density, pH0, pH24, the meat color, the cooking loss, the drip loss, the shear force and the dry matter in breast muscle and thigh muscle between corn flour groups and three sugars groups (P > 0.05). The crude fat content of breast muscle in fructose group was significantly higher than that in sucrose group (P < 0.05); the inosinic acid content of leg muscle in fructose group was significantly higher than that in the sucrose group (P < 0.05); the ratios of essential amino acids to total amino acids (EAA/TAA) in the breast muscle of maize flour group, fructose group, sucrose group and glucose group were 42%, 35%, 32% or 34%;57%, 64%, 64%, and 62%, respectively; the ratios of essential amino acids to total amino acids in leg muscle of maize flour group, fructose group, sucrose group and glucose group were 31%, 33%, 35%, and 34%, respectively. The contents of C16:1 and C18:1 n-9c in breast muscle in fructose group were significantly higher than that in sucrose group (P < 0.05). Compared with maize flour group, the contents of C18:0 and C20:0 were lower in leg muscle of sugar group (P < 0.05). Compared with the maize flour group, the activities of hydrogen peroxide (H2O2) and glutathione peroxidase (GSH-PX) in breast muscle were higher than those of sucrose group (P < 0.05), the total antioxidant capacity (T-AOC) levels in breast muscle was higher than that of fructose group and sucrose group (P < 0.05). Cluster analysis and principal component analysis (PCA) showed that there was no difference in meat quality between maize flour and sugar group. In conclusion, the overfeeding with maize flour supplement with 10% sugar had no evident influence on the meat quality.
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Peróxido de Hidrogênio , Açúcares , Animais , Galinhas , Carne/análise , Gansos/fisiologia , Frutose , Glucose , Aminoácidos/análise , Aminoácidos Essenciais , SacaroseRESUMO
Messenger ribonucleic acids (mRNAs) comprise a class of small nucleic acids carrying genetic information, which exhibit very important role in medical research and diagnosis. If only the mean mRNA expression levels of the mRNA population are considered in medical research, important information linking mRNA expression and cellular function may be lost. Single-cell analysis provides valuable insights into studying its heterogeneity, signaling, and stochastic gene expression. In this study, a "bunge bedstraw herb"-type DNA machine based on DNAzyme catalyzing coupled clamping hybrid chain reaction (c-HCR) is presented. In the DNA machine, a bunge bedstraw herb-type DNA structure was first formed by hybridizing a core junction scaffold cruciform probe to a hairpin probe that can trigger the c-HCR via a target molecule in four directions. This approach can reduce the detection limit of mRNA to 5 × 10-15 M. Absolute quantification of survivin mRNA in individual cells was achieved using the DNA machine on a microfluidic chip electrophoresis platform. The reported method represents an unprecedented single-cell analysis platform for single-cell biology studies.
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Técnicas Biossensoriais , DNA Catalítico , Galium , Técnicas Biossensoriais/métodos , DNA/química , DNA/genética , DNA Catalítico/química , Galium/genética , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico/métodos , Hibridização de Ácido Nucleico/métodos , RNA Mensageiro/análise , RNA Mensageiro/genética , Survivina/genéticaRESUMO
The interaction between light and biological tissues in the second near-infrared (NIR-II) window is weak, which can effectively reduce the scattering and absorption of incoming light by biological tissues and enhance the resolution and sensing ability of in vivo photoacoustic (PA) imaging. In particular, tissues that carry blood and water produce the lowest PA background in the wavelength range of 1050 to 1150 nm. However, the development of the NIR-II PA probe for the above window faces great challenges. To tackle this challenge, the reduction-reoxidation of an organic dye was used to develop a PA imaging probe (Hydro-1048) as the first NIR-II PA probe of a hydroxy radical (·OH) for molecular imaging in deep tissue. The ·OH oxidized the C-N single bond in Hydro-1048 to double bonds, which formed Et-1065. This conversion extended the conjugate system of the molecule and shifted the absorption peak from 520 to 1065 nm, which resulted in a strong PA signal after irradiation with a 1065 nm laser. At a detection limit of 0.6 nM, a good linear relationship within the range of 5-1000 nM was obtained for the PA signal intensity versus the concentration of ·OH. The developed NIR-II PA probe can be used for the noninvasive high-resolution imaging of ·OH in deep tissue, and the PA imaging of ·OH can also be used to visually monitor in situ pathological processes related to hepatitis.