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1.
Anal Methods ; 16(8): 1281-1287, 2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38327233

RESUMO

MiRNAs are critical regulators of target gene expression in many biological processes and are considered promising biomarkers for diseases. In this study, we developed a simple, specific, and sensitive miRNA detection method based on proximity ligation reaction, which is easy to operate. The method uses a pair of target-specific DNA probes immobilized on the same gold nanoparticles (AuNPs), which hybridize to the target miRNA. Hybridization brings the probes close together, allowing the formation of a continuous DNA sequence that can be amplified by Quantitative Real-time PCR (qPCR). This method eliminates the need for complex reverse transcription design and achieves high specificity for discriminating single base mismatches between miRNAs through a simple procedure. This method can sensitively measure three different miRNAs with a detection limit of 20 aM, providing high versatility and sensitivity, even distinguishing single-base variations among members of the miR-200 family with high selectivity. Due to its high selectivity and sensitivity, this method has important implications for the investigation of miRNA biological functions and related biomedical research.


Assuntos
Nanopartículas Metálicas , MicroRNAs , MicroRNAs/genética , MicroRNAs/análise , Ouro , Ácidos Nucleicos Imobilizados , Limite de Detecção
2.
Anal Chem ; 95(6): 3499-3506, 2023 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-36718639

RESUMO

The immobilization of DNA to surfaces is required for numerous biosensing applications related to the capture of target DNA sequences, proteins, or small-molecule analytes from solution. For these applications to be successful, the chemistry of DNA immobilization should be efficient, reproducible, and stable and should allow the immobilized DNA to adopt a secondary structure required for association with its respective target molecule. To develop and characterize surface immobilization chemistry to meet this challenge, it is invaluable to have a quantitative, surface-sensitive method that can report the interfacial chemistry at each step, while also being capable of determining the structure, stability, and activity of the tethered DNA product. In this work, we develop a method to immobilize DNA to silica, glass, or other oxide surfaces by carrying out the reactions in porous silica particles. Due to the high specific surface area of porous silica, the local concentrations of surface-immobilized molecules within the particle are sufficiently high that interfacial chemistry can be monitored at each step of the process with confocal Raman microscopy, providing a unique capability to assess the molecular composition, structure, yield, and surface coverage of these reactions. We employ this methodology to investigate the steps for immobilizing thiolated-DNA to thiol-modified silica surfaces through sequential Michael addition reactions with the cross-linker 1,4-phenylene-bismaleimide. A key advantage of employing a phenyl-bismaleimide over a comparable alkyl coupling reagent is the efficient conversion of the initial phenyl-thiosuccinimide to a more stable succinamic acid thioether linkage. This transformation was confirmed by in situ Raman spectroscopy measurements, and the resulting succinamic acid thioether product exhibited greater than 95% retention of surface-immobilized DNA after 12 days at room temperature in aqueous buffer. Confocal Raman microscopy was also used to assess the conformational freedom of surface-immobilized DNA by comparing the structure of a 23-mer DNA hairpin sequence under duplex-forming and unfolding conditions. We find that the immobilized DNA hairpin can undergo reversible intramolecular duplex formation based on the changes in frequencies and intensities of the phosphate backbone and base-specific vibrational modes that are informative of the hybridization state of DNA.


Assuntos
Ácidos Nucleicos Imobilizados , Dióxido de Silício , Dióxido de Silício/química , DNA/química , Hibridização de Ácido Nucleico , Microscopia Confocal , Propriedades de Superfície
3.
Anal Biochem ; 658: 114928, 2022 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-36162448

RESUMO

In the present work, an aptasensing method based on integration of RNA on Cu-MOF was developed for detection of C-Reactive Protein (CRP). Cu-MOF showed stimulated fluorescence and mimetic peroxidase enzymatic activity at the time and can be used as dual-signal transduction. CRP binding RNA was used as a highly selective recognition element and immobilized on the Cu-MOF. The immobilized RNA can block the peroxidase activity and fluorescence of the signal traducer probe. Adding CRP to the RNA/Cu-MOF will release RNA from the surface of Cu-MOF and recover both the stimulated fluorescence and peroxidase activity. A biosensor was built for detection of CRP using the two modes of transduction, either colorimetry or fluorometry. A dynamic linear range was obtained from 0.1 to 50 ng mL -1with a limit of detection (LOD) as small as 40 pg mL -1was calculated in fluorescence mode and 240 pg mL -1 as LOD in colorimetry mode. The LODs are lower than the LOD of nephelometric techniques used in clinical practice and is comparable to the normal clinical cutoff value in high-sensitivity CRP assays (1 µg/mL). The aptasensor was successfully applied for detection of CRP in Covid-19 patients with spike recoveries between 84 and 102% and RSD from 0.94% to 2.05%.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , COVID-19 , Humanos , Proteína C-Reativa , Ácidos Nucleicos Imobilizados , Técnicas Biossensoriais/métodos , Limite de Detecção , Peroxidase , RNA
4.
ACS Appl Mater Interfaces ; 14(26): 29483-29490, 2022 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-35700238

RESUMO

A highly precise and sensitive technology that enables DNA amplification/detection from minimal amounts of nucleic acid is expected to find applicability in genetic testing involving small amounts of samples. The use of a free enzyme in conventional DNA amplification techniques, such as the polymerase chain reaction (PCR), frequently causes side reactions (i.e., nonspecific DNA amplification) when ≤103 substrate DNA molecules are present, thereby preventing selective amplification of the target DNA. To address this issue, we have developed a novel DNA amplification system, mesoporous silica-enhanced PCR (MSE-PCR), which involves the immobilization of a thermostable DNA polymerase from Thermococcus kodakaraensis (KOD DNA polymerase) into highly ordered nanopores of the mesoporous silica to control the reaction environment around the enzyme. In the MSE-PCR system using immobilized KOD DNA polymerase, such nonspecific DNA amplification was remarkably inhibited under the same conditions. Furthermore, the optimization of mesoporous silica pore sizes enabled selective and efficient DNA amplification from DNA substrates at the single-molecule level, i.e., one ten-thousandth of the amount of substrate DNA required for a DNA amplification reaction using a free enzyme. The results obtained in this study have shown that the nanopores of mesoporous silica can inhibit nonspecific reactions in DNA amplification, thereby considerably improving the specificity and sensitivity of the DNA polymerase reaction.


Assuntos
Enzimas Imobilizadas , Dióxido de Silício , DNA , DNA Polimerase Dirigida por DNA/química , Enzimas Imobilizadas/genética , Ácidos Nucleicos Imobilizados/química , Reação em Cadeia da Polimerase/métodos , Dióxido de Silício/química
5.
J Am Chem Soc ; 144(7): 3174-3181, 2022 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-35143189

RESUMO

The therapeutic use of small interfering RNAs (siRNAs) as gene regulation agents has been limited by their poor stability and delivery. Although arranging siRNAs into a spherical nucleic acid (SNA) architecture to form siRNA-SNAs increases their stability and uptake, prototypical siRNA-SNAs consist of a hybridized architecture that causes guide strand dissociation from passenger strands, which limits the delivery of active siRNA duplexes. In this study, a new SNA design that directly attaches both siRNA strands to the SNA core through a single hairpin-shaped molecule to prevent guide strand dissociation is introduced and investigated. This hairpin-like architecture increases the number of siRNA duplexes that can be loaded onto an SNA by 4-fold compared to the original hybridized siRNA-SNA architecture. As a result, the hairpin-like siRNA-SNAs exhibit a 6-fold longer half-life in serum and decreased cytotoxicity. In addition, the hairpin-like siRNA-SNA produces more durable gene knockdown than the hybridized siRNA-SNA. This study shows how the chemistry used to immobilize siRNA on nanoparticles can markedly enhance biological function, and it establishes the hairpin-like architecture as a next-generation SNA construct that will be useful in life science and medical research.


Assuntos
Ácidos Nucleicos Imobilizados/farmacologia , RNA Interferente Pequeno/farmacologia , Linhagem Celular Tumoral , Inativação Gênica/efeitos dos fármacos , Ouro/química , Humanos , Ácidos Nucleicos Imobilizados/química , Ácidos Nucleicos Imobilizados/toxicidade , Sequências Repetidas Invertidas , Nanopartículas Metálicas/química , Nanopartículas Metálicas/toxicidade , Hibridização de Ácido Nucleico , RNA Interferente Pequeno/química , RNA Interferente Pequeno/toxicidade
6.
J Mater Chem B ; 10(3): 450-455, 2022 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-34981801

RESUMO

The simple and sensitive detection of protein is of great significance in biological research and medical diagnosis. However, the commonly-used methods, such as enzyme-linked immunosorbent assay (ELISA), usually rely on signal tags labeled on the antibody, which limits the sensitivity and stability. Herein, we have designed and constructed a colorimetric immunosensor in this work for the analysis of protein by taking advantage of 2D metal-organic framework (2D-MOF) nanomaterials as enzyme mimics. The nanomaterial shows a strong peroxidase mimetic activity, and good selectivity after it is modified with a specific aptamer. Therefore, taking carcinoembryonic antigen (CEA) as an example, this immunosensor achieves a good detection performance with a linear range from 1 pg mL-1 to 1000 ng mL-1 and a limit of detection (LOD) of 0.742 pg mL-1. Moreover, the sensor can successfully distinguish the human serum of colorectal cancer patients from healthy people, which suggests that this sensor has great potential in clinical applications. More importantly, the mass production, low cost, stability and ease of transport of the MOFs nanomaterials, as well as the ability for visual detection will make this sensor suitable for point-of-care (POC) testing in remote or resource-poor areas.


Assuntos
Antígeno Carcinoembrionário/sangue , Colorimetria/métodos , Imunoensaio/métodos , Estruturas Metalorgânicas/química , Nanoestruturas/química , Anticorpos Imobilizados/imunologia , Aptâmeros de Nucleotídeos/química , Benzidinas/química , Biomarcadores/sangue , Antígeno Carcinoembrionário/imunologia , Catálise , Compostos Cromogênicos/química , Neoplasias Colorretais/sangue , Humanos , Ácidos Nucleicos Imobilizados/química , Limite de Detecção
7.
Int J Mol Sci ; 23(1)2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-35008982

RESUMO

Nucleic acid aptamers specific to S-protein and its receptor binding domain (RBD) of SARS-CoV-2 (severe acute respiratory syndrome-related coronavirus 2) virions are of high interest as potential inhibitors of viral infection and recognizing elements in biosensors. Development of specific therapy and biosensors is complicated by an emergence of new viral strains bearing amino acid substitutions and probable differences in glycosylation sites. Here, we studied affinity of a set of aptamers to two Wuhan-type RBD of S-protein expressed in Chinese hamster ovary cell line and Pichia pastoris that differ in glycosylation patterns. The expression system for the RBD protein has significant effects, both on values of dissociation constants and relative efficacy of the aptamer binding. We propose glycosylation of the RBD as the main force for observed differences. Moreover, affinity of a several aptamers was affected by a site of biotinylation. Thus, the robustness of modified aptamers toward new virus variants should be carefully tested.


Assuntos
Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/metabolismo , Ácidos Nucleicos Imobilizados/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo , Animais , Sítios de Ligação , Células CHO , Cricetulus , Glicosilação , Ligação Proteica , Domínios Proteicos , Domínios e Motivos de Interação entre Proteínas , Processamento de Proteína Pós-Traducional , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , SARS-CoV-2 , Saccharomycetales/genética
8.
J Phys Chem Lett ; 13(5): 1249-1257, 2022 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-35089049

RESUMO

Single-molecule Förster resonance energy transfer (smFRET) is widely utilized to investigate the structural heterogeneity and dynamics of biomolecules. However, it has been difficult to simultaneously achieve a wide observation time window, a high structure resolution, and a high time resolution with the current smFRET methods. Herein, we introduce a new method utilizing two-dimensional fluorescence lifetime correlation spectroscopy (2D FLCS) and surface immobilization techniques. This method, scanning 2D FLCS, enables us to examine the structural heterogeneity and dynamics of immobilized biomolecules on a time scale from microsecond to subsecond by slowly scanning the sample stage at the rate of ∼1 µm/s. Application to the DNA Holliday junction (HJ) complex under various [Mg2+] conditions demonstrates that scanning 2D FLCS enables tracking reaction kinetics from 25 µs to 30 ms with a time resolution as high as 1 µs. Furthermore, the high structure resolution of scanning 2D FLCS allows us to unveil the ensemble nature of each isomer state and the heterogeneity of the dynamics of the HJ.


Assuntos
DNA Cruciforme , DNA/química , Espectrometria de Fluorescência/métodos , Corantes Fluorescentes/química , Ácidos Nucleicos Imobilizados/química , Isomerismo , Cinética , Rodaminas/química , Fatores de Tempo
9.
ACS Appl Mater Interfaces ; 14(4): 5615-5623, 2022 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-35050582

RESUMO

A simple fluorescence and electrochemical dual-channel biosensor based on bifunctional Zr(IV)-based metal-organic framework (Zr-MOF) was proposed to detect Ochratoxin A (OTA). The bifunctional Zr-MOF, with photoluminescence properties and enormous electroactive ligands, was exploited to load OTA-specific aptamers for designing signal probes, greatly simplifying the probe-fabrication process and improving sensing reliability. Upon specific recognition of aptamer toward OTA, the anchored probe was released from the sensing interface into the reaction solution. In this circumstance, the increased amount of the signal probe in reaction solution led to an enhanced fluorescence response, while the decreased amount of the signal probe on the sensing interface resulted in a diminished electrochemical response. According to the dual-channel signal change with increasing OTA concentration, the visual fluorescence strategy was established for intuitive OTA detection, and meanwhile, sensitive electrochemical assay with a detection limit of 0.024 pg/mL was also achieved with the help of one-step electrodeposition as a sensing platform. Moreover, the proposed dual-channel assay has been successfully applied to determine OTA levels in corn samples with rapid response, superior accuracy, and high anti-interference capability, providing a promising method for food safety monitoring.


Assuntos
Técnicas Biossensoriais/métodos , Estruturas Metalorgânicas/química , Ocratoxinas/análise , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/instrumentação , DNA/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Contaminação de Alimentos/análise , Ouro/química , Ácidos Nucleicos Imobilizados/química , Limite de Detecção , Ocratoxinas/química , Zea mays/química , Zircônio/química
10.
J Am Chem Soc ; 144(4): 1498-1502, 2022 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-34928591

RESUMO

Several applications in health diagnostics, food, safety, and environmental monitoring require rapid, simple, selective, and quantitatively accurate viral load monitoring. Here, we introduce the first label-free biosensing method that rapidly detects and quantifies intact virus in human saliva with single-virion resolution. Using pseudotype SARS-CoV-2 as a representative target, we immobilize aptamers with the ability to differentiate active from inactive virions on a photonic crystal, where the virions are captured through affinity with the spike protein displayed on the outer surface. Once captured, the intrinsic scattering of the virions is amplified and detected through interferometric imaging. Our approach analyzes the motion trajectory of each captured virion, enabling highly selective recognition against nontarget virions, while providing a limit of detection of 1 × 103 copies/mL at room temperature. The approach offers an alternative to enzymatic amplification assays for point-of-collection diagnostics.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , DNA/química , Ácidos Nucleicos Imobilizados/química , SARS-CoV-2/isolamento & purificação , Técnicas Biossensoriais/instrumentação , Humanos , Limite de Detecção , Microscopia/métodos , Óptica e Fotônica/instrumentação , Óptica e Fotônica/métodos , SARS-CoV-2/química , Saliva/virologia , Glicoproteína da Espícula de Coronavírus/química
11.
Mikrochim Acta ; 188(11): 397, 2021 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-34716495

RESUMO

A simple nanoplatform based on molybdenum disulfide (MoS2) nanosheets, a fluorescence quencher (signal off), and a hybridization chain reaction (HCR) signal amplification (signal on) used for the enzyme-free, label-free, and low-background signal quantification of microRNA-21 in plasma exosome is reported. According to the sequence of microRNA-21, carboxy-fluorescein (FAM)-labeled hybridization probe 1 (FAM-H1) and hybridization probes 2 (FAM-H2) were designed with excitation maxima at 488 nm and emission maxima at 518 nm. MoS2 nanosheets could adsorb FAM-H1 and FAM-H2 and quenched their fluorescence signals to reduce the background signal. However, HCR was triggered when microRNA-21 was present. Consequently, HCR products containing a large number of FAM fluorophores can emit a strong fluorescence at 518 nm and could realize the detection of microRNA-21 as low as 6 pmol/L and had a wide linear relation of 0.01-25 nmol/L. This assay has the ability of single-base mismatch recognition and could identify microRNA-21 with high specificity. Most importantly, this approach was successfully applied to the detection of plasma exosomal microRNA-21 in patients with lung cancer, and it is proposed that other targets can also be detected by changing the FAM-H1 and FAM-H2 corresponding to the target sequence. Thus, a novel, hands-on strategy for liquid biopsy was proposed and has a potential application value in the early diagnosis of lung cancer.


Assuntos
Exossomos/química , Neoplasias Pulmonares/sangue , MicroRNAs/sangue , Sondas de DNA/química , Sondas de DNA/genética , Dissulfetos/química , Corantes Fluorescentes/química , Humanos , Ácidos Nucleicos Imobilizados/química , Ácidos Nucleicos Imobilizados/genética , Limite de Detecção , Neoplasias Pulmonares/diagnóstico , MicroRNAs/genética , Molibdênio/química , Nanoestruturas/química , Hibridização de Ácido Nucleico , Espectrometria de Fluorescência
12.
Mikrochim Acta ; 188(11): 398, 2021 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-34716815

RESUMO

A simple carbon nanodot-based electrogenerated chemiluminescence biosensor is described for sensitive and selective detection of microRNA-21 (miRNA-21), a biomarker of several pathologies including cardiovascular diseases (CVDs). The photoluminescent carbon nanodots (CNDs) were obtained using a new synthesis method, simply by treating tiger nut milk in a microwave reactor. The synthesis is environmentally friendly, simple, and efficient. The optical properties and morphological characteristics of the CNDs were exhaustively investigated, confirming that they have oxygen and nitrogen functional groups on their surfaces and exhibit excitation-dependent fluorescence emission, as well as photostability. They act as co-reactant agents in the anodic electrochemiluminescence (ECL) of [Ru(bpy)3]2+, producing different signals for the probe (single-stranded DNA) and the hybridized target (double-stranded DNA). These results paved the way for the development of a sensitive ECL biosensor for the detection of miRNA-21. This was developed by immobilization of a thiolated oligonucleotide, fully complementary to the miRNA-21 sequence, on the disposable gold electrode. The target miRNA-21 was hybridized with the probe on the electrode surface, and the hybridization was detected by the enhancement of the [Ru(bpy)3]2+/DNA ECL signal using CNDs. The biosensor shows a linear response to miRNA-21 concentration up to 100.0 pM with a detection limit of 0.721 fM. The method does not require complex labeling steps, and has a rapid response. It was successfully used to detect miRNA-21 directly in serum samples from heart failure patients without previous RNA extraction neither amplification process.


Assuntos
Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Substâncias Luminescentes/química , Medições Luminescentes/métodos , MicroRNAs/sangue , Pontos Quânticos/química , Técnicas Biossensoriais/instrumentação , Carbono/química , Complexos de Coordenação/química , Técnicas Eletroquímicas/instrumentação , Eletrodos , Ouro/química , Insuficiência Cardíaca/sangue , Humanos , Ácidos Nucleicos Imobilizados/genética , Limite de Detecção , Medições Luminescentes/instrumentação , Masculino , MicroRNAs/genética , Hibridização de Ácido Nucleico , Oligodesoxirribonucleotídeos/química , Oligodesoxirribonucleotídeos/genética , Compostos de Rutênio/química
13.
Chem Commun (Camb) ; 57(87): 11465-11468, 2021 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-34651618

RESUMO

Detection and characterization of DNA damage plays a critical role in genotoxicity testing, drug screening, and environmental health. We developed a fully integrated origami paper-based analytical device (oPAD) for measuring DNA damage. This simple device allows on-paper cell lysis, DNA extraction, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) reaction and signal readout with simple operation steps, enabling rapid (within 30 min) and high throughput assessment of multiple DNA damages induced by exogenous chemical agents.


Assuntos
Dano ao DNA , DNA/análise , Papel , Animais , Linhagem Celular , DNA/química , DNA Nucleotidilexotransferase/química , Fluoresceínas/química , Corantes Fluorescentes/química , Ácidos Nucleicos Imobilizados/análise , Ácidos Nucleicos Imobilizados/química , Marcação In Situ das Extremidades Cortadas , Microscopia Confocal/instrumentação , Microscopia Confocal/métodos , Microscopia de Fluorescência/instrumentação , Microscopia de Fluorescência/métodos , Peixe-Zebra
14.
ACS Appl Mater Interfaces ; 13(42): 49754-49761, 2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34657424

RESUMO

A reliable and sensitive detection approach for SARS-CoV 2 is essential for timely infection diagnosis and transmission prevention. Here, a two-dimensional (2D) metal-organic framework (MOF)-based photoelectrochemical (PEC) aptasensor with high sensitivity and stability for SARS-CoV 2 spike glycoprotein (S protein) detection was developed. The PEC aptasensor was constructed by a plasmon-enhanced photoactive material (namely, Au NPs/Yb-TCPP) with a specific DNA aptamer against S protein. The Au NPs/Yb-TCPP fabricated by in situ growth of Au NPs on the surface of 2D Yb-TCPP nanosheets showed a high electron-hole (e-h) separation efficiency due to the enhancement effect of plasmon, resulting in excellent photoelectric performance. The modified DNA aptamer on the surface of Au NPs/Yb-TCPP can bind with S protein with high selectivity, thus decreasing the photocurrent of the system due to the high steric hindrance and low conductivity of the S protein. The established PEC aptasensor demonstrated a highly sensitive detection for S protein with a linear response range of 0.5-8 µg/mL with a detection limit of 72 ng/mL. This work presented a promising way for the detection of SARS-CoV 2, which may conduce to the impetus of clinic diagnostics.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Estruturas Metalorgânicas/química , SARS-CoV-2/química , Glicoproteína da Espícula de Coronavírus/análise , Sequência de Bases , Técnicas Biossensoriais/instrumentação , COVID-19/diagnóstico , DNA/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Ouro/química , Ouro/efeitos da radiação , Humanos , Ácidos Nucleicos Imobilizados/química , Luz , Limite de Detecção , Nanopartículas Metálicas/química , Nanopartículas Metálicas/efeitos da radiação , Faringe/virologia , Processos Fotoquímicos , Porfirinas/química , Glicoproteína da Espícula de Coronavírus/química , Itérbio/química
15.
Mikrochim Acta ; 188(11): 396, 2021 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-34714421

RESUMO

Rapid and sensitive detection of enteropathogenic Escherichia coli (EPEC) in fluids with complex background is an important task for safety quality control in the field of medicine, environment, and food. In this study, a gold foil paper-based aptasensor was developed for the detection of enteropathogenic EPEC O26:K60 with surface-enhanced Raman spectroscopy (SERS) and magnetic separation technology mediated by Fe3O4@Au composite. The gold foil paper was firstly modified with thiolated capture probe and SERS tag. The thiolated aptamer probe for EPEC was immobilized onto a Fe3O4@Au composite. In the presence of EPEC, highly specific recognition between the aptamer probe and EPEC made the Fe3O4@Au composite partially dissociated from the gold foil paper. This led to a decreased Raman intensity response, which showed an obvious negative linear correlation with increasing concentration of EPEC over a wide concentration range from 10 to 107 CFU/mL under an excitation wavelength of 633 nm. The detection limit was about 2.86 CFU/mL in a buffer solution and a licorice extractum and the detection time was only 2.5 h. The results demonstrate that the gold foil paper-based aptasensor can be an excellent biosensing platform that offers a reliable, rapid, and sensitive alternative for EPEC detection.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Escherichia coli Enteropatogênica/isolamento & purificação , Ouro/química , Papel , Ácidos Borônicos/química , Escherichia coli Enteropatogênica/química , Glycyrrhiza/microbiologia , Ácidos Nucleicos Imobilizados/química , Limite de Detecção , Fenômenos Magnéticos , Nanopartículas de Magnetita/química , Nanocompostos/química , Análise Espectral Raman , Compostos de Sulfidrila/química
16.
Mikrochim Acta ; 188(10): 326, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34494176

RESUMO

Plasmonic nanosensors for label-free detection of DNA require excellent sensing resolution, which is crucial when monitoring short DNA sequences, as these induce tiny peak shifts, compared to large biomolecules. We report a versatile and simple strategy for plasmonic sensor signal enhancement by assembling multiple (four) plasmonic sensors in series. This approach provided a fourfold signal enhancement, increased signal-to-noise ratio, and improved sensitivity for DNA detection. The response of multiple sensors based on AuNSpheres was also compared with  AuNRods, the latter showing better sensing resolution. The amplification system based on AuNR was integrated into  a microfluidic sequential injection platform and applied to the monitoring of DNA, specifically from environmental invasive species-zebra mussels. DNA from zebra mussels was log concentration-dependent from 1 to 1 × 106 pM, reaching a detection limit of 2.0 pM. In situ tests were also successfully applied to real samples, within less than 45 min, using DNA extracted from zebra mussel meat. The plasmonic nanosensors' signal can be used as a binary output (yes/no) to assess the presence of those invasive species. Even though these genosensors were applied to the monitoring of DNA in environmental samples, they potentially offer advantage in a wide range of fields, such as disease diagnostics.


Assuntos
DNA/análise , Técnicas Analíticas Microfluídicas/métodos , Ressonância de Plasmônio de Superfície/métodos , Animais , DNA/genética , Sondas de DNA/química , Sondas de DNA/genética , Dreissena/química , Ouro/química , Ácidos Nucleicos Imobilizados/química , Ácidos Nucleicos Imobilizados/genética , Dispositivos Lab-On-A-Chip , Técnicas Analíticas Microfluídicas/instrumentação , Nanosferas/química , Nanotubos/química , Hibridização de Ácido Nucleico , Alimentos Marinhos/análise
17.
ACS Appl Mater Interfaces ; 13(36): 43668-43675, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34473482

RESUMO

The efficient recognition of circulating tumor cells (CTCs) with an aptamer probe confers numerous benefits; however, the stability and binding affinity of aptamers are significantly hampered in real biological sample matrices. Inspired by the efficient preying mechanism by multiplex tubing feet and endoskeletons of sea urchins, we engineered a superefficient biomimetic single-CTC recognition platform by conjugating dual-multivalent-aptamers (DMAs) Sgc8 and SYL3C onto AuNPs to form a sea urchin-like nanoprobe (sea urchin-DMA-AuNPs). Aptamers Sgc8 and SYL3C selectively bind with the biomarker proteins PTK7 and EpCAM expressed on the surface of CTCs. CTCs were captured with 100% efficiency, followed by sorting on a specially designed multifunctional microfluidic configuration, integrating a single-CTC separation unit and a hydrodynamic filtrating purification unit. After sorting, background-free analysis of biomarker proteins in single CTCs was undertaken with inductively coupled plasma mass spectrometry by measuring the amount of 197Au isotope in sea urchin-DMA-AuNPs. With respect to a single-aptamer nanoprobe/-interface, the dual-aptamer nanoprobe improves the binding efficiency by more than 200% (Kd < 0.35 nM). The microchip facilitates the recognition of single CTCs with a sorting separation rate of 93.6% at a flow rate of 60 µL min-1, and it exhibits 73.8 ± 5.0% measurement efficiency for single CTCs. The present strategy ensures the manipulation and detection of a single CTC in 100 µL of whole blood within 1 h.


Assuntos
Aptâmeros de Nucleotídeos/química , Separação Celular/métodos , Ácidos Nucleicos Imobilizados/química , Dispositivos Lab-On-A-Chip , Nanopartículas Metálicas/química , Células Neoplásicas Circulantes/química , Materiais Biomiméticos/química , Moléculas de Adesão Celular/química , Linhagem Celular Tumoral , Molécula de Adesão da Célula Epitelial/química , Ouro/química , Humanos , Espectrometria de Massas , Técnicas Analíticas Microfluídicas/métodos , Receptores Proteína Tirosina Quinases/química
18.
ACS Appl Mater Interfaces ; 13(38): 45291-45299, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34542269

RESUMO

Dynamic imaging of cell surface pH is extremely challenging due to the slight changes in pH and the fast diffusion of secreted acid to the extracellular environment. In this work, we construct a novel metal-organic framework (MOF)-shell-confined i-motif-based pH probe (MOFC-i) strategy that enables sensitive and dynamic imaging of cell surface pH. The CY3- and CY5-labeled i-motif, which is hybridized via its short complementary chain with two-base mismatches, is optimized for sensing at physiological pH. After efficiently anchoring the optimized pH probes onto the cell membrane with the aid of cholesterol groups, a biocompatible microporous MOF shell is then formed around the cell by cross-linking ZIF-8 nanoparticles via tannic acid. The microporous MOF shell can confine secreted acid without inhibiting the normal physiological activities of cells; thus, the MOFC-i strategy can be used to monitor dynamic changes in the cell surface pH of living cells. Furthermore, this method can not only clearly distinguish the different metabolic behaviors of cancer cells and normal cells but also reveal drug effects on the cell surface pH or metabolism, providing promising prospects in pH-related diagnostics and drug screening.


Assuntos
Membrana Celular/metabolismo , Sondas de DNA/química , DNA de Cadeia Simples/química , Corantes Fluorescentes/química , Imidazóis/química , Estruturas Metalorgânicas/química , Carbocianinas/química , Membrana Celular/efeitos dos fármacos , DNA Complementar/química , Estradiol/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Ácidos Nucleicos Imobilizados , Células MCF-7 , Motivos de Nucleotídeos , Piruvatos/farmacologia
19.
ACS Appl Mater Interfaces ; 13(38): 45214-45223, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34524789

RESUMO

Accurate and sensitive fluorescence imaging of intracellular miRNA is essential for understanding the mechanism underlying some physiological and pathological events, as well as the prevention and diagnosis of diseases. Herein, a highly sensitive ratiometric fluorescent nanoprobe for intracellular miRNA imaging was fabricated by integrating a Ru-SiO2@polydopamine (Ru-SiO2@PDA) nanoplatform with a near-infrared light (NIR)-assisted DNA strand displacement signal amplification strategy. The Ru-SiO2@PDA spheres have excellent biosafety, high photothermal effect, and unique photophysical properties that can both emit a stable red fluorescence and well quench the fluorophores getting closer to them. So, when the fuel DNA and carboxyfluorescein (FAM)-labeled signal DNA are co-assembled on their outer surfaces, the FAM's green fluorescence is quenched, and a low ratiometric signal is obtained. However, in the presence of miRNA, the target displaces the signal DNA from the capture DNA, releasing the signal DNA far away from the Ru-SiO2@PDA. Then, the green fluorescence recovers and leads to an enhanced Igreen/Ired value. Under NIR light irradiation, the Ru-SiO2@PDA increases the local temperature around the probe and triggers the release of fuel DNA, which thus recycles the target miRNA and effectively amplifies the ratiometric signal. Using A549 cells as a model, the nanoprobe realizes the highly sensitive ratiometric fluorescence imaging of miRNA let-7a, as well as its in vivo up- and down-regulation expressions. It provides a facile tool for highly sensitive and accurate intracellular miRNA detection through one-step incubation and may pave a new avenue for single-cell analysis.


Assuntos
Corantes Fluorescentes/química , MicroRNAs/análise , Nanopartículas/química , Células A549 , DNA/química , DNA/genética , Regulação para Baixo , Humanos , Ácidos Nucleicos Imobilizados/química , Ácidos Nucleicos Imobilizados/genética , Indóis/química , Raios Infravermelhos , Limite de Detecção , MicroRNAs/genética , MicroRNAs/metabolismo , Microscopia Confocal , Microscopia de Fluorescência , Hibridização de Ácido Nucleico , Polímeros/química , Rutênio/química , Dióxido de Silício/química , Regulação para Cima
20.
Mikrochim Acta ; 188(10): 333, 2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34498149

RESUMO

Nucleic acid amplification tests (NAATs) are powerful tools for the Japanese encephalitis virus (JEV). We demonstrated highly sensitive, specific, and rapid detection of JEV by colorimetric reverse-transcription loop-mediated isothermal amplification (cRT-LAMP). Under optimized conditions, the RT-LAMP assay results showed that the limit of detection was approximately equivalent to 1 RNA genome copy/µL with an assay time of 30 min. The assay was highly specific to JEV when tested with other mosquito-borne virus panels (Zika virus and dengue virus types 2-4). The ability to detect JEV directly from crude human sample matrices (serum and urine) demonstrated the suitability of our JEV RT-LAMP for widespread clinical application. The JEV RT-LAMP provides combination of  rapid colorimetric determination of true-positive JEV RT-LAMP amplicons with our recently developed JEV-nanobarcodes, measured at absorbance wavelenght of 530 (A530) and 650 (A650), which have a limit of detection of 23.3 ng/µL. The AuNP:polyA10-JEV RT-LAMP nanobarcodes exhibited superior capability for stabilizing the true-positive JEV RT-LAMP amplicons against salt-induced AuNP aggregation, which improved the evaluation of true/false positive signals in the assay. These advances enable to expand the use of RT-LAMP for point-of-care tests, which will greatly bolster JEV clinical programs. The JEV RT-LAMP nanobarcode assay targeting the envelope (E) gene and MgSO4 induced AuNP aggregation, indicated by an instant pink-to-violet colorimetric read-out.


Assuntos
Colorimetria/métodos , Vírus da Encefalite Japonesa (Espécie)/química , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , RNA Viral/análise , Animais , Sequência de Bases , Sangue/virologia , Ouro/química , Humanos , Ácidos Nucleicos Imobilizados/química , Limite de Detecção , Nanopartículas Metálicas/química , Poli A/química , RNA Viral/sangue , RNA Viral/urina , Suínos , Urina/virologia
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