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1.
Molecules ; 26(5)2021 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-33800379

RESUMO

Membrane proteins such as G protein-coupled receptors (GPCRs) exert fundamental biological functions and are involved in a multitude of physiological responses, making these receptors ideal drug targets. Drug discovery programs targeting GPCRs have been greatly facilitated by the emergence of high-resolution structures and the resulting opportunities to identify new chemical entities through structure-based drug design. To enable the determination of high-resolution structures of GPCRs, most receptors have to be engineered to overcome intrinsic hurdles such as their poor stability and low expression levels. In recent years, multiple engineering approaches have been developed to specifically address the technical difficulties of working with GPCRs, which are now beginning to make more challenging receptors accessible to detailed studies. Importantly, successfully engineered GPCRs are not only valuable in X-ray crystallography, but further enable biophysical studies with nuclear magnetic resonance spectroscopy, surface plasmon resonance, native mass spectrometry, and fluorescence anisotropy measurements, all of which are important for the detailed mechanistic understanding, which is the prerequisite for successful drug design. Here, we summarize engineering strategies based on directed evolution to reduce workload and enable biophysical experiments of particularly challenging GPCRs.


Assuntos
Engenharia de Proteínas/métodos , Receptores Acoplados a Proteínas G/genética , Cristalografia por Raios X/métodos , Desenho de Fármacos , Descoberta de Drogas/métodos , Proteínas de Ligação ao GTP/metabolismo , Humanos , Espectroscopia de Ressonância Magnética/métodos , Modelos Moleculares , Conformação Proteica , Receptores Acoplados a Proteínas G/metabolismo , Ressonância de Plasmônio de Superfície/métodos
2.
Commun Biol ; 4(1): 70, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33452375

RESUMO

The proliferation and transmission of viruses has become a threat to worldwide biosecurity, as exemplified by the current COVID-19 pandemic. Early diagnosis of viral infection and disease control have always been critical. Virus detection can be achieved based on various plasmonic phenomena, including propagating surface plasmon resonance (SPR), localized SPR, surface-enhanced Raman scattering, surface-enhanced fluorescence and surface-enhanced infrared absorption spectroscopy. The present review covers all available information on plasmonic-based virus detection, and collected data on these sensors based on several parameters. These data will assist the audience in advancing research and development of a new generation of versatile virus biosensors.


Assuntos
/diagnóstico , Pandemias , Análise Espectral Raman/métodos , Ressonância de Plasmônio de Superfície/métodos , /virologia , Humanos , Nanoestruturas/química , Espectrometria de Fluorescência/métodos , Espectrofotometria Infravermelho/métodos
3.
Int J Mol Sci ; 22(2)2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33467468

RESUMO

The bottom-up design of smart nanodevices largely depends on the accuracy by which each of the inherent nanometric components can be functionally designed with predictive methods. Here, we present a rationally designed, self-assembled nanochip capable of capturing a target protein by means of pre-selected binding sites. The sensing elements comprise computationally evolved peptides, designed to target an arbitrarily selected binding site on the surface of beta-2-Microglobulin (ß2m), a globular protein that lacks well-defined pockets. The nanopatterned surface was generated by an atomic force microscopy (AFM)-based, tip force-driven nanolithography technique termed nanografting to construct laterally confined self-assembled nanopatches of single stranded (ss)DNA. These were subsequently associated with an ssDNA-peptide conjugate by means of DNA-directed immobilization, therefore allowing control of the peptide's spatial orientation. We characterized the sensitivity of such peptide-containing systems against ß2m in solution by means of AFM-based differential topographic imaging and surface plasmon resonance (SPR) spectroscopy. Our results show that the confined peptides are capable of specifically capturing ß2m from the surface-liquid interface with micromolar affinity, hence providing a viable proof-of-concept for our approach to peptide design.


Assuntos
Biologia Computacional/métodos , DNA de Cadeia Simples/metabolismo , Peptídeos/metabolismo , Microglobulina beta-2/metabolismo , Sítios de Ligação/genética , Técnicas Biossensoriais/métodos , DNA de Cadeia Simples/química , DNA de Cadeia Simples/genética , Humanos , Cinética , Microscopia de Força Atômica/métodos , Simulação de Dinâmica Molecular , Peptídeos/química , Peptídeos/genética , Ligação Proteica , Ressonância de Plasmônio de Superfície/métodos , Microglobulina beta-2/química , Microglobulina beta-2/genética
4.
Molecules ; 26(3)2021 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-33498632

RESUMO

Through a simple 1,3-cycloaddition reaction, three BODIPY-peptide conjugates that target the extracellular domain of the epidermal growth factor receptor (EGFR) were prepared and their ability for binding to EGFR was investigated. The peptide ligands K(N3)LARLLT and its cyclic analog cyclo(K(N3)larllt, previously shown to have high affinity for binding to the extracellular domain of EGFR, were conjugated to alkynyl-functionalized BODIPY dyes 1 and 2 via a copper-catalyzed click reaction. This reaction produced conjugates 3, 4, and 5 in high yields (70-82%). In vitro studies using human carcinoma HEp2 cells that overexpress EGFR demonstrated high cellular uptake, particularly for the cyclic peptide conjugate 5, and low cytotoxicity in light (~1 J·cm-2) and darkness. Surface plasmon resonance (SPR) results show binding affinity of the three BODIPY-peptide conjugates for EGFR, particularly for 5 bearing the cyclic peptide. Competitive binding studies using three cell lines with different expressions of EGFR show that 5 binds specifically to EGFR-overexpressing colon cancer cells. Among the three conjugates, 5 bearing the cyclic peptide exhibited the highest affinity for binding to the EGFR protein.


Assuntos
Compostos de Boro/química , Boro/química , Corantes Fluorescentes/química , Peptídeos Cíclicos/química , Porfobilinogênio/análogos & derivados , Linhagem Celular Tumoral , Receptores ErbB/metabolismo , Humanos , Ligantes , Porfobilinogênio/química , Ligação Proteica , Ressonância de Plasmônio de Superfície/métodos
5.
Anal Bioanal Chem ; 413(4): 1225-1236, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33404749

RESUMO

In this work, a surface plasmon resonance (SPR)-based assay for the quantification of antineoplastic drug irinotecan in human plasma samples has been developed for the first time. The selective binding of irinotecan with an aptamer receptor, operating in human plasma, allowed to set-up a novel analytical methodology to detect the drug in the analytical range of interest by using SPR as detection technique. After hybridizing the aptamer to the sensing platform and optimizing the sample preparation procedure, a quantitative assay was validated according to FDA regulatory guidelines. The analytical working range was found between 100 and 7500 ng mL-1 with negligible interferences from plasma components and co-medication associated with the administration of irinotecan. The utility of the new SPR assay was confirmed by analyzing plasma samples in parallel with LC-MS as reference technique, providing a new analytical tool for the therapeutic drug monitoring of irinotecan in patients under chemotherapy regimens.


Assuntos
Antineoplásicos/sangue , Aptâmeros de Nucleotídeos/química , Irinotecano/sangue , Ressonância de Plasmônio de Superfície/métodos , Monitoramento de Medicamentos/métodos , Humanos , Limite de Detecção , Hibridização de Ácido Nucleico/métodos
6.
Anal Chem ; 93(2): 828-833, 2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33319993

RESUMO

A variety of surface plasmon resonance (SPR) sensing devices have been extensively used in biochemical detection for their characteristics of label-free, highly sensitive, and faster detecting. Among them, the spectrum-based SPR sensing devices have offered us great advantages in high-throughput sensing due to their large dynamic range and the possibility of detection resolution similar to that offered by angle interrogation. This paper demonstrates a spectrum-based SPR imaging sensing system with fast wavelength scanning capability achieved by an acousto-optic tunable filter (AOTF) and a low-cost and speckle-free halogen lamp implemented as the SPR excitation source. Especially, we developed a novel four-parameter-based spectral curve readjusting (4-PSCR) method for data processing, which offered us a faster and more accurate spectral data curve fitting process than the traditional polynomial fitting method. With the configuration, we have also conducted an SPR high-throughput detection of the novel coronavirus (COVID-19) spike protein, proving its application possibility in the screening of COVID-19 with high accuracy. We believe that the higher sensitivity and accuracy of the system have made it readily used in biochemical imaging and detecting applications.


Assuntos
Glicoproteína da Espícula de Coronavírus/análise , Ressonância de Plasmônio de Superfície/métodos , Algoritmos , /virologia , Humanos , Limite de Detecção , Óptica e Fotônica , /metabolismo , Glicoproteína da Espícula de Coronavírus/metabolismo , Ressonância de Plasmônio de Superfície/instrumentação , Temperatura
7.
Methods Mol Biol ; 2237: 55-67, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33237408

RESUMO

The coupling of surface plasmon resonance imaging (SPRi) with mass spectrometry (MS) offers a very promising multidimensional analysis. This system takes advantage of the two well-established techniques: SPR, which allows for the analysis of biomolecular interactions through the determination of kinetic and thermodynamic constants, and MS, which can characterize biological structures from mass measurements and fragmentation experiments. Here, a protocol for the coupling of SPRi with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is described using a biochip grafted by antibodies in an array format. Interaction between ß-lactoglobulin antibodies and the protein antigen is detected and analyzed by SPRi. Then, the arrayed biochip which fitted a commercially MALDI target was inserted in a MALDI source, and mass spectra were recorded directly from the biochip surface from each antibody spot, showing protein ions attributed to the corresponding specific protein antigens.


Assuntos
Antígenos/análise , Espectrometria de Massas/métodos , Análise Serial de Proteínas/métodos , Ressonância de Plasmônio de Superfície/métodos , Antígenos/imunologia , Imunoensaio/instrumentação , Imunoensaio/métodos , Dispositivos Lab-On-A-Chip , Espectrometria de Massas/instrumentação , Análise Serial de Proteínas/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação
8.
Molecules ; 26(1)2020 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-33374387

RESUMO

The novel coronavirus disease (2019-nCoV) has been affecting global health since the end of 2019, and there is no sign that the epidemic is abating. Targeting the interaction between the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein and the human angiotensin-converting enzyme 2 (ACE2) receptor is a promising therapeutic strategy. In this study, surface plasmon resonance (SPR) was used as the primary method to screen a library of 960 compounds. A compound 02B05 (demethylzeylasteral, CAS number: 107316-88-1) that had high affinities for S-RBD and ACE2 was discovered, and binding affinities (KD, µM) of 02B05-ACE2 and 02B05-S-RBD were 1.736 and 1.039 µM, respectively. The results of a competition experiment showed that 02B05 could effectively block the binding of S-RBD to ACE2 protein. Furthermore, pseudovirus infection assay revealed that 02B05 could inhibit entry of SARS-CoV-2 pseudovirus into 293T cells to a certain extent at nontoxic concentration. The compoundobtained in this study serve as references for the design of drugs which have potential in the treatment of COVID-19 and can thus accelerate the process of developing effective drugs to treat SARS-CoV-2 infections.


Assuntos
/metabolismo , Domínios e Motivos de Interação entre Proteínas/efeitos dos fármacos , Ressonância de Plasmônio de Superfície/métodos , Triterpenos/farmacologia , Proteínas Virais/metabolismo , Células HEK293 , Humanos , Ligação Proteica
9.
PLoS One ; 15(9): e0239632, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32970749

RESUMO

In recent years, there has been growing concern among consumers about pesticide contamination in fruits. Therefore, rapid, reliable, and consistent detection methods for OPPs, especially dimethoate, are crucially needed. The existing quantitative methods for detecting dimethoate are not suitable for rapid measuring system such as the dimethoate samples from two channels. Hence this paper examines the utilization of a dual-channel system for utilize the absorption variations of the Localized Surface Plasmon Resonance (LSPR) bands of gold nanoparticles (AuNPs) were investigate for detection of dimethoate. Under optimized conditions, the relationship between concentrations of dimethoate and absorbance ratios (A(520)/A(640)) was linearly found in the concentration range of 10-100 nM. Result from the experiment shows that both channels exhibit a linear correlation coefficient as high as 0.97 and a limit of detection (LOD) as low as 5.5 nM. This LSPR detection system was characterized by testing the dimethoate in apple samples and the recovery rates were found to be in the range of 85.90% to 107.37%. The proposed dual-channel LSPR system for detecting dimethoate creating a new approach for detecting organophosphate insecticide in agricultural fields. It could lay the foundation for designing a high-throughput analysis of the insecticides using a wavelength division multiplexing switch (WDMS).


Assuntos
Produtos Agrícolas/normas , Dimetoato/análise , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Frutas/normas , Inseticidas/análise , Ressonância de Plasmônio de Superfície/métodos , Produtos Agrícolas/química , Análise de Alimentos/normas , Frutas/química , Sensibilidade e Especificidade , Ressonância de Plasmônio de Superfície/normas
10.
Nat Commun ; 11(1): 4772, 2020 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-32973145

RESUMO

Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for vibrational spectroscopy as it provides several orders of magnitude higher sensitivity than inherently weak spontaneous Raman scattering by exciting localized surface plasmon resonance (LSPR) on metal substrates. However, SERS can be unreliable for biomedical use since it sacrifices reproducibility, uniformity, biocompatibility, and durability due to its strong dependence on "hot spots", large photothermal heat generation, and easy oxidization. Here, we demonstrate the design, fabrication, and use of a metal-free (i.e., LSPR-free), topologically tailored nanostructure composed of porous carbon nanowires in an array as a SERS substrate to overcome all these problems. Specifically, it offers not only high signal enhancement (~106) due to its strong broadband charge-transfer resonance, but also extraordinarily high reproducibility due to the absence of hot spots, high durability due to no oxidization, and high compatibility to biomolecules due to its fluorescence quenching capability.


Assuntos
Carbono/química , Nanofios/química , Análise Espectral Raman/métodos , Fluorescência , Porosidade , Reprodutibilidade dos Testes , Ressonância de Plasmônio de Superfície/métodos , Propriedades de Superfície
11.
ACS Sens ; 5(9): 2663-2678, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32786383

RESUMO

The global sanitary crisis caused by the emergence of the respiratory virus SARS-CoV-2 and the COVID-19 outbreak has revealed the urgent need for rapid, accurate, and affordable diagnostic tests to broadly and massively monitor the population in order to properly manage and control the spread of the pandemic. Current diagnostic techniques essentially rely on polymerase chain reaction (PCR) tests, which provide the required sensitivity and specificity. However, its relatively long time-to-result, including sample transport to a specialized laboratory, delays massive detection. Rapid lateral flow tests (both antigen and serological tests) are a remarkable alternative for rapid point-of-care diagnostics, but they exhibit critical limitations as they do not always achieve the required sensitivity for reliable diagnostics and surveillance. Next-generation diagnostic tools capable of overcoming all the above limitations are in demand, and optical biosensors are an excellent option to surpass such critical issues. Label-free nanophotonic biosensors offer high sensitivity and operational robustness with an enormous potential for integration in compact autonomous devices to be delivered out-of-the-lab at the point-of-care (POC). Taking the current COVID-19 pandemic as a critical case scenario, we provide an overview of the diagnostic techniques for respiratory viruses and analyze how nanophotonic biosensors can contribute to improving such diagnostics. We review the ongoing published work using this biosensor technology for intact virus detection, nucleic acid detection or serological tests, and the key factors for bringing nanophotonic POC biosensors to accurate and effective COVID-19 diagnosis on the short term.


Assuntos
Betacoronavirus , Infecções por Coronavirus/diagnóstico , Nanoestruturas/química , Pneumonia Viral/diagnóstico , Ressonância de Plasmônio de Superfície/métodos , Antígenos Virais/análise , Betacoronavirus/química , Betacoronavirus/isolamento & purificação , Técnicas de Laboratório Clínico , Genoma Viral , Humanos , Imunoensaio/métodos , Nanoestruturas/efeitos da radiação , Pandemias , Testes Sorológicos/métodos
12.
Sensors (Basel) ; 20(17)2020 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-32842601

RESUMO

The global burden of coronavirus disease 2019 (COVID-19) to public health and global economy has stressed the need for rapid and simple diagnostic methods. From this perspective, plasmonic-based biosensing can manage the threat of infectious diseases by providing timely virus monitoring. In recent years, many plasmonics' platforms have embraced the challenge of offering on-site strategies to complement traditional diagnostic methods relying on the polymerase chain reaction (PCR) and enzyme-linked immunosorbent assays (ELISA). This review compiled recent progress on the development of novel plasmonic sensing schemes for the effective control of virus-related diseases. A special focus was set on the utilization of plasmonic nanostructures in combination with other detection formats involving colorimetric, fluorescence, luminescence, or Raman scattering enhancement. The quantification of different viruses (e.g., hepatitis virus, influenza virus, norovirus, dengue virus, Ebola virus, Zika virus) with particular attention to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) was reviewed from the perspective of the biomarker and the biological receptor immobilized on the sensor chip. Technological limitations including selectivity, stability, and monitoring in biological matrices were also reviewed for different plasmonic-sensing approaches.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas Biossensoriais , Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , Ressonância de Plasmônio de Superfície/métodos , Betacoronavirus/patogenicidade , Colorimetria , Infecções por Coronavirus/virologia , Fluorescência , Humanos , Nanoestruturas/química , Pandemias , Pneumonia Viral/virologia , Análise Espectral Raman
13.
Food Chem ; 332: 127431, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32645668

RESUMO

Illegal usage of ß-agonists as the animal growth promoters can lead to multiple harmful impacts to public health, thus detection of ß-agonists at trace level in complex sample matrixes is of great importance. In recent years, emergence of advanced nanomaterials greatly facilitates the advancement of sensors in terms of sensitivity, specificity and robustness. Plenty of nanoparticles-based sensors have been developed for ß-agonists determination. In this review, we comprehensively summarized the construction of emerging nanoparticles-based sensors (including colorimetric sensors, fluorescent sensors, chemiluminescent sensors, electrochemical sensors, electrochemiluminescent sensors, surface enhanced Raman scattering sensors, surface plasmon resonance sensors, quartz crystal microbalance sensors, etc.), and nanomaterial-based enzyme-linked immunosorbent assay (nano-ELISA). Impressively, the applications of nanoparticles-based sensors and nano-ELISAs in the detection of ß-agonists have also been summarized and discussed. In the end, future opportunities and challenges in the design construction of nanoparticles (NPs)-based sensors and their applications in ß-agonist assay are tentatively proposed.


Assuntos
Agonistas Adrenérgicos/análise , Nanoestruturas/química , Animais , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Colorimetria/instrumentação , Colorimetria/métodos , Humanos , Nanotecnologia/instrumentação , Nanotecnologia/métodos , Análise Espectral Raman/instrumentação , Análise Espectral Raman/métodos , Ressonância de Plasmônio de Superfície/instrumentação , Ressonância de Plasmônio de Superfície/métodos
14.
Opt Express ; 28(12): 18479-18492, 2020 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-32680046

RESUMO

Biomolecule sensing plays an important role in both fundamental biological studies and medical diagnostic applications. Infrared (IR) spectroscopy presents opportunities for sensing biomolecules as it allows their fingerprints to be determined by directly measuring their absorption spectra. However, the detection of biomolecules at low concentrations is difficult with conventional IR spectroscopy due to signal-to-noise considerations. This has led to recent interest on the use of nanostructured surfaces to boost the signals from biomolecules in a method termed surface enhanced infrared spectroscopy. So far, efforts have largely involved the use of metallic nanoantennas (which produce large field enhancement) or graphene nanostructures (which produce strong field confinement and provide electrical tunability). Here, we propose a nanostructured surface that combines the large field enhancement of metallic nanoantennas with the strong field confinement and electrical tunability of graphene plasmons. Our device consists of an array of plasmonic nanoantennas and graphene nanoslits on a resonant substrate. We perform systematic electromagnetic simulations to quantify the sensing performance of the proposed device and show that it outperforms designs in which only plasmons from metallic nanoantennas or plasmons from graphene are utilized. These investigations consider the model system of a representative protein-goat anti-mouse immunoglobulin G (IgG) - in monolayer or sub-monolayer form. Our findings provide guidance for future biosensors for the sensitive quantification and identification of biomolecules.


Assuntos
Grafite , Nanopartículas Metálicas , Espectrofotometria Infravermelho/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Desenho de Equipamento/métodos , Proteínas/análise , Ressonância de Plasmônio de Superfície/métodos
15.
PLoS One ; 15(6): e0233443, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32497056

RESUMO

Large (> 1 µm) tumor-derived extracellular vesicles (tdEVs) enriched from the cell fraction of centrifuged whole blood are prognostic in metastatic castration-resistant prostate cancer (mCRPC) patients. However, the highest concentration of tdEVs is expected in the cell-free plasma fraction. In this pilot study, we determine whether mCRPC patients can be discriminated from healthy controls based on detection of tdEVs (< 1µm, EpCAM+) and/or other EVs, in cell-free plasma and/or urine. The presence of marker+ EVs in plasma and urine samples from mCRPC patients (n = 5) and healthy controls (n = 5) was determined by flow cytometry (FCM) and surface plasmon resonance imaging (SPRi) using an antibody panel and lactadherin. For FCM, the concentrations of marker positive (+) particles and EVs (refractive index <1.42) were determined. Only the lactadherin+ particle and EV concentration in plasma measured by FCM differed significantly between patients and controls (p = 0.017). All other markers did not result in signals exceeding the background on both FCM and SPRi, or did not differ significantly between patients and controls. In conclusion, no difference was found between patients and controls based on the detection of tdEVs. For FCM, the measured sample volumes are too small to detect tdEVs. For SPRi, the concentration of tdEVs is probably too low to be detected. Thus, to detect tdEVs in cell-free plasma and/or urine, EV enrichment and/or concentration is required. Furthermore, we recommend testing other markers and/or a combination of markers to discriminate mCRPC patients from healthy controls.


Assuntos
Adenocarcinoma/secundário , Vesículas Extracelulares/metabolismo , Citometria de Fluxo/métodos , Neoplasias de Próstata Resistentes à Castração/sangue , Neoplasias de Próstata Resistentes à Castração/urina , Ressonância de Plasmônio de Superfície/métodos , Adenocarcinoma/sangue , Adenocarcinoma/urina , Idoso , Idoso de 80 Anos ou mais , Antígenos de Superfície/sangue , Biomarcadores Tumorais , Linhagem Celular Tumoral , Meios de Cultivo Condicionados , Vesículas Extracelulares/química , Humanos , Masculino , Proteínas do Leite/sangue , Proteínas de Neoplasias/sangue , Proteínas de Neoplasias/urina , Projetos Piloto , Neoplasias de Próstata Resistentes à Castração/patologia
16.
Food Chem ; 331: 127163, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32593037

RESUMO

Herein, a surface plasmon resonance (SPR) enhanced DNA biosensor has been developed for real-time detection of donkey meat marker using biotinylated reporter and streptavidin functionalized gold nanostars (Stre@GNSs). Compared to the direct detection assay, this sandwich format for the enhancement of the signal, resulted in 6-folds orders increase in the sensitivity. Target DNA could be detected with the lower limit of quantification (LLOQ) of 1.0 nM with a relative standard deviation (RSD, n = 3) of 0.85%. In addition, the fabricated SPR sensor showed good selectivity for the target analyte over full complementary, single-base mismatch, three base-mismatch and non-complementary oligonucleotides. Finally, the proposed sensor was successfully applied for detection of donkey meat adulteration with various percentages in homemade beef sausage, as a real sample. The results indicated that the proposed biosensor provides a high specificity, easy, good sensitivity and fast approach for identification of donkey meat adulteration in food samples.


Assuntos
Técnicas Biossensoriais/métodos , Equidae/genética , Contaminação de Alimentos/análise , Carne/análise , Animais , Técnicas Biossensoriais/instrumentação , DNA/análise , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Ouro/química , Limite de Detecção , Microscopia Eletrônica de Transmissão , Nanoestruturas/química , Espectrofotometria Ultravioleta , Estreptavidina/química , Ressonância de Plasmônio de Superfície/métodos
17.
Food Chem ; 329: 127160, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32485646

RESUMO

In this study, we developed an indirect competitive plasmonic immunoassay using glucose oxidase (GOx)-induced redox reaction to etch Au nanorods (AuNRs) for qualitative and quantitative detection of aflatoxin M1 (AFM1) in milk. In this system, streptavidin (SA) was selected as a linker between biotinylated anti-AFM1-monoantibody (bio-mAb) and biotinylated GOx (bio-GOx) to form the immunocomplexes bio-mAb-SA-bio-GOx. After the oxidation of the glucose and I-, the resultant I2 could etch cetytrimethylammonium bromide (CTAB)-stabilized AuNRs. This resulted in the blue shift of the longitudinal localized surface plasmon resonance (LSPR) extinction peak, with a color change from blue to pink. The linear range and limit of detection (LOD) of the plasmonic immunoassay were 0.25-10 ng mL-1 and 0.11 ng mL-1, respectively. It displayed quantitative detection with high sensitivity, specificity, recovery, and accuracy, which is promising for qualitative and quantitative detection of AFM1 in food safety.


Assuntos
Aflatoxina M1/análise , Contaminação de Alimentos/análise , Imunoensaio/métodos , Leite/química , Nanotubos , Animais , Glucose/química , Glucose Oxidase/química , Ouro/química , Imunoensaio/instrumentação , Limite de Detecção , Nanotubos/química , Sensibilidade e Especificidade , Ressonância de Plasmônio de Superfície/métodos
18.
Cancer Immunol Immunother ; 69(9): 1833-1840, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32350593

RESUMO

BACKGROUND: Bladder cancer is diagnosed by the use of several biomarkers, including survivin. This protein has an important role in the cancer progression by controlling the rate of cell apoptosis. Findings show that there is no survivin in normal tissues, whereas the level of survivin expression increases in tumor cells. DESIGN: The purpose of this study was to specify the reactive antibodies to survivin protein as a biomarker to determine the bladder cancer stage with ELISA method and using GNPs conjugated with survivin antibody. The serum and urine samples of patients with bladder cancer were collected among those referred to Sina Hospital, Tehran, Iran. The survivin protein level was measured in the serum and urine by ELISA technique and in the urine by GNPs conjugated with survivin. RESULTS: Based on the results of ELISA, the serum and urinary levels of survivin increased significantly in T3 and T4 stages of the disease (high grades), compared with the healthy individuals. Also, using conjugated GNPs, survivin protein was detected in the urine specimens of patients at all grades (low and high grades). CONCLUSION: Our findings showed that using the ELISA technique, the increased level of survivin could be identified in high grades of bladder cancer, but using anti-survivin antibody-conjugated GNPs, bladder cancer can be detected in early stages. The applied method was found to be a rapid tool, dependent on visible color changes and colorimetric detection, without any need for reader devices.


Assuntos
Anticorpos/metabolismo , Ouro/administração & dosagem , Nanopartículas Metálicas/administração & dosagem , Survivina/metabolismo , Neoplasias da Bexiga Urinária/diagnóstico , Neoplasias da Bexiga Urinária/metabolismo , Biomarcadores Tumorais/metabolismo , Feminino , Humanos , Masculino , Sensibilidade e Especificidade , Ressonância de Plasmônio de Superfície/métodos
19.
ACS Nano ; 14(6): 7617-7627, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32437124

RESUMO

The current outbreak of the pandemic coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) demands its rapid, convenient, and large-scale diagnosis to downregulate its spread within as well as across the communities. But the reliability, reproducibility, and selectivity of majority of such diagnostic tests fail when they are tested either to a viral load at its early representation or to a viral gene mutated during its current spread. In this regard, a selective "naked-eye" detection of SARS-CoV-2 is highly desirable, which can be tested without accessing any advanced instrumental techniques. We herein report the development of a colorimetric assay based on gold nanoparticles (AuNPs), when capped with suitably designed thiol-modified antisense oligonucleotides (ASOs) specific for N-gene (nucleocapsid phosphoprotein) of SARS-CoV-2, could be used for diagnosing positive COVID-19 cases within 10 min from the isolated RNA samples. The thiol-modified ASO-capped AuNPs agglomerate selectively in the presence of its target RNA sequence of SARS-CoV-2 and demonstrate a change in its surface plasmon resonance. Further, the addition of RNaseH cleaves the RNA strand from the RNA-DNA hybrid leading to a visually detectable precipitate from the solution mediated by the additional agglomeration among the AuNPs. The selectivity of the assay has been monitored in the presence of MERS-CoV viral RNA with a limit of detection of 0.18 ng/µL of RNA having SARS-CoV-2 viral load. Thus, the current study reports a selective and visual "naked-eye" detection of COVID-19 causative virus, SARS-CoV-2, without the requirement of any sophisticated instrumental techniques.


Assuntos
Betacoronavirus/genética , Técnicas Biossensoriais/métodos , Infecções por Coronavirus/diagnóstico , Nanopartículas Metálicas , Proteínas do Nucleocapsídeo/genética , Oligonucleotídeos Antissenso/genética , Pneumonia Viral/diagnóstico , Sequência de Bases , Betacoronavirus/isolamento & purificação , Colorimetria/métodos , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/virologia , Genes Virais , Ouro , Humanos , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Transmissão , Nanotecnologia/métodos , Pandemias , Fosfoproteínas , Pneumonia Viral/epidemiologia , Pneumonia Viral/virologia , Capuzes de RNA/genética , RNA Viral/genética , Ressonância de Plasmônio de Superfície/métodos
20.
ACS Nano ; 14(5): 5268-5277, 2020 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-32281785

RESUMO

The ongoing outbreak of the novel coronavirus disease (COVID-19) has spread globally and poses a threat to public health in more than 200 countries. Reliable laboratory diagnosis of the disease has been one of the foremost priorities for promoting public health interventions. The routinely used reverse transcription polymerase chain reaction (RT-PCR) is currently the reference method for COVID-19 diagnosis. However, it also reported a number of false-positive or -negative cases, especially in the early stages of the novel virus outbreak. In this work, a dual-functional plasmonic biosensor combining the plasmonic photothermal (PPT) effect and localized surface plasmon resonance (LSPR) sensing transduction provides an alternative and promising solution for the clinical COVID-19 diagnosis. The two-dimensional gold nanoislands (AuNIs) functionalized with complementary DNA receptors can perform a sensitive detection of the selected sequences from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) through nucleic acid hybridization. For better sensing performance, the thermoplasmonic heat is generated on the same AuNIs chip when illuminated at their plasmonic resonance frequency. The localized PPT heat is capable to elevate the in situ hybridization temperature and facilitate the accurate discrimination of two similar gene sequences. Our dual-functional LSPR biosensor exhibits a high sensitivity toward the selected SARS-CoV-2 sequences with a lower detection limit down to the concentration of 0.22 pM and allows precise detection of the specific target in a multigene mixture. This study gains insight into the thermoplasmonic enhancement and its applicability in the nucleic acid tests and viral disease diagnosis.


Assuntos
Betacoronavirus/química , Técnicas Biossensoriais/métodos , Ressonância de Plasmônio de Superfície/métodos , Betacoronavirus/genética , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/normas , DNA Complementar/química , DNA Complementar/genética , Ouro/química , Temperatura Alta , Nanopartículas Metálicas/química , Hibridização de Ácido Nucleico/métodos , Ressonância de Plasmônio de Superfície/instrumentação , Ressonância de Plasmônio de Superfície/normas
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