Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 4.072
Filtrar
1.
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 , Pneumonia Viral/epidemiologia , Pneumonia Viral/virologia , Capuzes de RNA/genética , RNA Viral/genética , Ressonância de Plasmônio de Superfície/métodos
2.
Int J Nanomedicine ; 15: 2085-2094, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32273704

RESUMO

Background: Pregnancy-associated plasma protein-A and -A2 (PAPP-A and -A2) are principally expressed in placental trophoblasts and play a critical role in the regulation of fetal and placental growth. PAPP-A2 shares 45% amino acid similarity with PAPP-A. This study aimed to investigate the efficacy of real-time detection of PAPP-A and PAPP-A2 using a novel surface plasmon resonance (SPR) biosensor based on graphene oxide (GO). Methods: Traditional SPR and GO-based SPR chips were fabricated to measure PAPP-A and PAPP-A2 concentrations. We compared SPR response curves of PAPP-A and PAPP-A2 between traditional SPR and GO-SPR biosensors. We also performed interference tests and specificity analyses among PAPP-A, PAPP-A2, and mixed interference proteins. Results: The time to detect PAPP-A and PAPP-A2 was about 150 seconds with both traditional SPR and GO-SPR biosensors. Approximately double SPR angle shifts were noted with the GO-SPR biosensor compared to the traditional SPR biosensor at a PAPP-A and PAPP-A2 concentration of 5 µg/mL. The limit of detection of the GO-SPR biosensor was as low as 0.5 ng/mL for both PAPP-A and PAPP-A2. Interference testing revealed that almost all of the protein bonded on the GO-SPR biosensor with anti-PAPP-A from the mixture of proteins was PAPP-A, and that almost no other proteins were captured except for PAPP-A2. However, the SPR signal of PAPP-A2 (5.75 mdeg) was much smaller than that of PAPP-A (13.76 mdeg). Similar results were noted with anti-PAPP-A2, where almost all of the protein bonded on the GO-SPR biosensor was PAPP-A2. The SPR signal of PAPP-A (5.17 mdeg) was much smaller than that of PAPP-A2 (13.94 mdeg). Conclusion: The GO-SPR biosensor could distinguish PAPP-A and PAPP-A2 from various mixed interference proteins with high sensitivity and specificity. It could potentially be used to measure PAPP-A and PAPP-A2 in clinical blood samples during pregnancy.


Assuntos
Proteína Plasmática A Associada à Gravidez/análise , Ressonância de Plasmônio de Superfície/instrumentação , Ressonância de Plasmônio de Superfície/métodos , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Reações Cruzadas , Desenho de Equipamento , Feminino , Grafite , Humanos , Imunoensaio/instrumentação , Imunoensaio/métodos , Gravidez
3.
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
4.
PLoS One ; 15(2): e0229659, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32101588

RESUMO

The cultivation of genetically modified organisms (GMO) continues to expand worldwide. Still, many consumers express concerns about the use of GMO in food or feed, and many countries have legislated on labelling systems to indicate the presence of GMO in commercial products. To deal with the increased number of GMO events and to address related regulations, alternative detection methods for GMO inspection are required. In this work, a genosensor based on Surface Plasmon Resonance under continuous flow was developed for the detection and quantification of a genetically modified soybean (event GTS 40-3-2). In a single chip, the simultaneous detection of the event-specific and the taxon-specific samples were achieved, whose detection limits were 20 pM and 16 pM, respectively. The reproducibility was 1.4%, which supports the use of the chip as a reliable and cost-effective alternative to other DNA-based techniques. The results indicate that the proposed method is a versatile tool for GMO quantification in food and feed samples.


Assuntos
Soja/genética , Ressonância de Plasmônio de Superfície/métodos , DNA de Plantas/genética , Alimentos Geneticamente Modificados/classificação , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Organismos Geneticamente Modificados/química , Organismos Geneticamente Modificados/genética , Plantas Geneticamente Modificadas/genética , Reprodutibilidade dos Testes
5.
Chemphyschem ; 21(3): 188-193, 2020 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-31912640

RESUMO

Tip-enhanced Raman spectroscopy (TERS) is a promising technique for structural studies of biological systems and biomolecules, owing to its ability to provide a chemical fingerprint with sub-diffraction-limit spatial resolution. This application of TERS has thus far been limited, due to difficulties in generating high field enhancements while maintaining biocompatibility. The high sensitivity achievable through TERS arises from the excitation of a localized surface plasmon resonance in a noble metal atomic force microscope (AFM) tip, which in combination with a metallic surface can produce huge enhancements in the local optical field. However, metals have poor biocompatibility, potentially introducing difficulties in characterizing native structure and conformation in biomolecules, whereas biocompatible surfaces have weak optical field enhancements. Herein, a novel, biocompatible, highly enhancing surface is designed and fabricated based on few-monolayer mica flakes, mechanically exfoliated on a metal surface. These surfaces allow the formation of coupled plasmon enhancements for TERS imaging, while maintaining the biocompatibility and atomic flatness of the mica surface for high resolution AFM. The capability of these substrates for TERS is confirmed numerically and experimentally. We demonstrate up to five orders of magnitude improvement in TERS signals over conventional mica surfaces, expanding the sensitivity of TERS to a wide range of non-resonant biomolecules with weak Raman cross-sections. The increase in sensitivity obtained through this approach also enables the collection of nanoscale spectra with short integration times, improving hyperspectral mapping for these applications. These mica/metal surfaces therefore have the potential to revolutionize spectromicroscopy of complex, heterogeneous biological systems such as DNA and protein complexes.


Assuntos
Silicatos de Alumínio/química , Materiais Biocompatíveis/química , Ouro/química , Microscopia de Força Atômica/instrumentação , DNA/análise , Microscopia de Força Atômica/métodos , Análise Espectral Raman/métodos , Ressonância de Plasmônio de Superfície/métodos
6.
PLoS One ; 15(1): e0227584, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31917807

RESUMO

Ultrasensitive detection of heavy metal ions in available water around us is a great challenge for scientists since long time. We developed an optical technique that combines Rayleigh scattering of UV light (365 nm) and post-sample fluorescence detection from colloidal silver (Ag) nanoparticles (NPs) having a surface plasmon resonance (SPR) band at 420 nm. The efficacy of the technique is tested by the detection of several model toxic ions, including mercury, lead, and methylmercury in aqueous media. The light scattering from the Hg-included/inflated Ag NPs at 395 nm was observed to saturate the light sensor even with ppm-order concentrations of Hg ions in the water sample. However, the pollutant is not detected at lower concentrations at this wavelength. Instead, the fluorescence of a high-pass filter (cut-off at 400 nm) at 520 nm is applied to detect pollutant concentrations of up to several hundreds of ppm in the water sample. We also detected lead and methylmercury as model pollutants in aqueous media and validated the efficacy of our strategy. Finally, we report the development of a working prototype based on the strategy developed for efficient detection of pollutants in drinking/agricultural water.


Assuntos
Monitoramento Ambiental/métodos , Nanopartículas Metálicas/química , Metais Pesados/análise , Poluentes Químicos da Água/análise , Monitoramento Ambiental/instrumentação , Desenho de Equipamento , Fluorescência , Limite de Detecção , Metais Pesados/química , Microscopia Eletrônica de Transmissão/instrumentação , Microscopia Eletrônica de Transmissão/métodos , Espalhamento de Radiação , Sensibilidade e Especificidade , Prata/química , Espectrofotometria Ultravioleta , Ressonância de Plasmônio de Superfície/métodos , Raios Ultravioleta , Poluição da Água/análise
7.
Anal Bioanal Chem ; 412(2): 507-519, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31807804

RESUMO

A biosensor device for the detection and characterization of protein-glycosaminoglycan interactions is being actively sought and constitutes the key to identifying specific carbohydrate ligands, an important issue in glycoscience. Mass spectrometry (MS) hyphenated methods are promising approaches for carbohydrate enrichment and subsequent structural characterization. In the study herein, we report the analysis of interactions between the glycosaminoglycans (GAGs) heparin (HP) and heparan sulfate (HS) and various cytokines by coupling surface plasmon resonance imaging (SPRi) for thermodynamic analysis method and MALDI-TOF MS for structural determination. To do so, we developed an SPR biochip in a microarray format and functionalized it with a self-assembled monolayer of short poly(ethylene oxide) chains for grafting the human cytokines stromal cell-derived factor-1 (SDF-1α), monocyte chemotactic protein-1 (MCP-1), and interferon-γ. The thermodynamic parameters of the interactions between these cytokines and unfractionated HP/HS and derived oligosaccharides were successively determined using SPRi monitoring, and the identification of the captured carbohydrates was carried out directly on the biochip surface using MALDI-TOF MS, revealing cytokine preferential affinity for GAGs. The MS identification was enhanced by on-chip digestion of the cytokine-bound GAGs with heparinase, leading to the detection of oligosaccharides likely involved in the binding sequence of GAG ligands. Although several carbohydrate array-based assays have been reported, this study is the first report of the successful analysis of protein-GAG interactions using SPRi-MS coupling.


Assuntos
Glicosaminoglicanos/metabolismo , Dispositivos Lab-On-A-Chip , Proteínas/metabolismo , Ressonância de Plasmônio de Superfície/métodos , Técnicas Biossensoriais , Cinética , Ligantes , Ligação Proteica , Termodinâmica
8.
Talanta ; 206: 120187, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514860

RESUMO

CA125/MUC16 is an ovarian tumor cell marker widely used as a biomarker in epithelial ovarian carcinoma. CA125/MUC16 is also used for evaluation of the ROMA (Risk of Ovarian Malignancy Algorithm) value. In this work, a Surface Plasmon Resonance Imaging (SPRI) biosensor for circulating CA125/MUC16 has been developed. The anti-MUC16 antibody was attached to a gold chip via a cysteamine linker. The EDS/NHS protocol was used for the covalent attachment of the antibody. The developed biosensor is specific for CA125/MUC16, and exhibits good recovery and acceptable precision. Its linear response range (2.2-150 U/ml) is well suited to determination of the marker in the blood serum of a healthy control group and, after appropriate dilution, of patients with ovarian cancer. CA125/MUC16 was determined in two series of real samples: blood serum from patients with ovarian cancer and endometrial cysts. The method was validated by parallel determination of the samples using the chemiluminescent Architect i2000 method.


Assuntos
Biomarcadores Tumorais/sangue , Técnicas Biossensoriais/métodos , Antígeno Ca-125/sangue , Proteínas de Membrana/sangue , Animais , Anticorpos Imobilizados/imunologia , Biomarcadores Tumorais/imunologia , Antígeno Ca-125/imunologia , Cistos/sangue , Endométrio/patologia , Feminino , Humanos , Limite de Detecção , Proteínas de Membrana/imunologia , Neoplasias Ovarianas/sangue , Coelhos , Ressonância de Plasmônio de Superfície/métodos
9.
BMC Biotechnol ; 19(1): 97, 2019 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-31829176

RESUMO

BACKGROUND: Immunogold labeling in combination with transmission electron microscopy analysis is a technique frequently used to correlate high-resolution morphology studies with detailed information regarding localization of specific antigens. Although powerful, the methodology has limitations and it is frequently difficult to acquire a stringent system where unspecific low-affinity interactions are removed prior to analysis. RESULTS: We here describe a combinatorial strategy where surface plasmon resonance and immunogold labeling are used followed by a direct analysis of the sensor-chip surface by scanning electron microscopy. Using this approach, we have probed the interaction between amyloid-ß fibrils, associated to Alzheimer's disease, and apolipoprotein E, a well-known ligand frequently found co-deposited to the fibrillar form of Aß in vivo. The results display a lateral binding of ApoE along the amyloid fibrils and illustrates how the gold-beads represent a good reporter of the binding. CONCLUSIONS: This approach exposes a technique with generic features which enables both a quantitative and a morphological evaluation of a ligand-receptor based system. The methodology mediates an advantage compared to traditional immunogold labeling since all washing steps can be monitored and where a high stringency can be maintained throughout the experiment.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Apolipoproteínas E/metabolismo , Imuno-Histoquímica/métodos , Microscopia Eletrônica de Varredura/métodos , Ressonância de Plasmônio de Superfície/métodos , Peptídeos beta-Amiloides/química , Apolipoproteínas E/química , Humanos , Ligação Proteica
10.
Mikrochim Acta ; 187(1): 20, 2019 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-31807965

RESUMO

A multi-channel localized surface plasmon resonance system is described for absorptiometric determination of abscisic acid (ABA). The system is making use of gold nanoparticles and consists of a broadband light source, a multi-channel alignment device, and a fiber spectrometer. The method is based on the specific interaction between an ABA-binding aptamer and ABA. This induces the growth of gold nanoparticles (AuNPs) functionalized with a polyadenine-tailed aptamer that act as optical probes. Different concentrations of ABA give rise to varied morphologies of grown AuNPs. This causes a change of absorption spectra which is recorded by the system. ABA can be quantified by measurement of the peak wavelength shifts of grown AuNPs. Under optimized conditions, this method shows a linear relationship in the 1 nM to 10 µM ABA concentration range. The detection limit is 0.51 nM. The sensitivity of the ABA assay is strongly improved compared to the method based on salt-induced AuNP aggregation. This is attributed to the use of a poly-A-tailed aptamer and the catalytic ability of AuNPs. In the actual application, the ABA concentration of ABA in fresh leaves of rice is measured with the maximum relative error of 8.03% in comparison with the ELISA method. Graphical abstractSchematic representation of an absorptiometric approach for determination of abscisic acid based on the growth of polyA-tailed aptamer-AuNPs probes and a multi-channel localized surface plasmon resonance system.


Assuntos
Ácido Abscísico/análise , Aptâmeros de Nucleotídeos/química , Ouro/química , Nanopartículas Metálicas/química , Poli A/química , Ressonância de Plasmônio de Superfície/métodos , Ácido Abscísico/química , Ácido Abscísico/metabolismo , Absorção Fisico-Química , Aptâmeros de Nucleotídeos/metabolismo , Sequência de Bases , Oryza/química
11.
Chem Commun (Camb) ; 56(2): 289-292, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31808471

RESUMO

A novel biosensor for the rapid detection of lead ions employing the optical properties of AuNPs, a lead-specific aptamer and a cationic peptide has been demonstrated. The limit of detection of the biosensor was 98.7 pM, the lowest so far obtained using colorimetry.


Assuntos
Aptâmeros de Nucleotídeos/química , Colorimetria/métodos , Chumbo/análise , Nanopartículas Metálicas/química , Peptídeos/química , Técnicas Biossensoriais/métodos , Cor , DNA/química , Ouro/química , Limite de Detecção , Ressonância de Plasmônio de Superfície/métodos
12.
Appl Opt ; 58(34): 9411-9420, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31873539

RESUMO

A novel surface plasmon resonance (SPR) biosensor based on Ag-Au bimetallic films with a hybrid structure of blue phosphorene (BlueP)/transition metal dichalcogenides (TMDCs) and graphene is presented. In order to improve the sensitivity, the thickness of silver and gold films is optimized to achieve minimum reflectivity and an adequate level of sensitivity; further, sensitivity for the monolayer BlueP/MoS2 and graphene structure is enhanced by 19.73%, with respect to a traditional sensor. Besides, the effect of layers of different Blue/TMDCs heterostructures to the sensitivity of the SPR biosensor is investigated, and the highest sensitivity with 335.4°/RIU for the bilayer BlueP/WS2 is obtained. Furthermore, distributions of the electric field and the changes of resonance angle to the refractive index of the sensing medium and prism in the visible regime are illustrated at optimal configuration. In virtue of highly sensitive characteristics, the proposed sensor structure will be a much better option to be employed for further biological detection.


Assuntos
Técnicas Biossensoriais/instrumentação , Grafite/química , Nanoestruturas/química , Ressonância de Plasmônio de Superfície/instrumentação , Elementos de Transição/química , Biopolímeros , Ouro/química , Modelos Teóricos , Sensibilidade e Especificidade , Prata/química , Ressonância de Plasmônio de Superfície/métodos
13.
Int J Nanomedicine ; 14: 6735-6748, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31686806

RESUMO

Background: Graphene-like material such as functionalized carboxyl-graphene oxide (carboxyl-GO) can be intelligently tuned to achieve particular properties for biological and chemical sensing applications. Methods: In this study, we propose a method to improve interference of non-specific proteins for use in human plasma assays. The highly specific interactions between molecules are an advantage of carboxyl-GO-based surface plasmon resonance (SPR) immunoassays, and this can be applied to spiked plasma samples with pregnancy-associated plasma protein A2 (PAPPA2). Results: The experiment results showed that carboxyl-GO could be used to modulate the plasmon resonance energy, work function and conductivity properties. In addition, carboxyl groups could be used to enhance the conduction of electrons between carboxyl-GO and Au electrodes due to the excellent conductivity and electron transfer rate. The carboxyl-GO-based SPR chip exhibited high sensitivity based on the electric field amplification effects of the composite dielectric material. Therefore, the surface electric field could be enhanced by electron transfer, thereby greatly improving the sensitivity of the sensing system. Enhanced electric field intensity was generated around the carboxyl-GO of 63.58 V/m, and the measured work function was 4.95 eV. The results showed that the carboxyl-GO-based SPR biosensor had high sensitivity, affinity and selective ability for PAPPA2 protein with a high association rate constant (ka) of 3.1 ×109 M-1 S-1 and a limit of detection of 0.01 pg/mL in spiked human plasma. Conclusion: The results showed a detection accuracy of protein in spiked plasma of >90% compared to PBS buffer, suggesting that the carboxyl-GO-based SPR biosensor could be used in assays of human plasma for early and late gynecological diseases. The future of this technology will be useful for the diagnosis and evaluation of the risk of early maternal preeclampsia and potentially in clinical applications for gestational diseases.


Assuntos
Grafite/química , Proteína Plasmática A Associada à Gravidez/análise , Ressonância de Plasmônio de Superfície/métodos , Feminino , Humanos , Cinética , Espectroscopia Fotoeletrônica , Gravidez , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier
14.
Opt Lett ; 44(23): 5707-5710, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31774759

RESUMO

Label-free single-nanoparticle detection is crucial for the fast detection of nanoparticles and viruses in environmental monitoring and biological sciences. In this Letter, benefiting from the leakage radiation that transforms the near-field surface plasmon polariton (SPP) distribution along the interface to the far field, we demonstrated the plasmonic imaging of single polystyrene nanoparticles with a particle size down to 39 nm. The imaging is composed of the localized enhancement and interference of SPPs. The localized enhancement is the result of the accumulation of charges around the nanoparticle, and it is connected to the size and refractive index of nanoparticles. The interference is induced by the coupling between the incident SPPs and the scattered SPPs, verified by extracting the interference fringe periodicity to be half of the SPP wavelength. Our study provides an in-depth physical understanding of plasmonic imaging of single nanoparticles, which paves the way for a fast identification of nanomaterials.


Assuntos
Nanopartículas , Poliestirenos/química , Ressonância de Plasmônio de Superfície/métodos
15.
Analyst ; 144(24): 7105-7129, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31663527

RESUMO

Biomarkers are unquestionable biological indicators for diagnosis and therapeutic interventions providing appropriate classification of a wide range of health disorders and risk factors. Nonetheless, the detection and quantification of biomarkers need to be tested with sufficient reliability by robust analytical methods in order to assure clinical performance in health care settings. Since the analytical performance is determined by the sensitivity and specificity of the method employed, techniques have been intensively refined in order to avoid the misinterpretation of results and undesirable bias. Although biomarkers can be detected with the existing analytical techniques, to reproducibly quantify them in decentralized settings or remote locations with the required accuracy is still a challenge. Currently, only a few point-of-care devices for biomarker evaluation are commercially available. Thus, more focused research efforts are needed to overcome these limitations in order to provide universal patient-centered care platforms. To this end, plasmonic biosensors can be conveniently used as portable diagnostic devices for attaining timely and cost-effective clinical outcomes. The development of enhanced performance based on nanoplasmonics technology opens the way for sensor miniaturization, multiplexing and point of care testing. This review covers recent advances and applications of plasmonic and nanoplasmonic biosensors intended for biomarker diagnosis in clinical practice, including cancer, cardiovascular and neurodegenerative diseases. The review specially focuses on: (i) recent progress in plasmonics development including the design of singular nanostructured surfaces, (ii) novel chemical functionalization strategies for the appropriate incorporation of bioreceptors and (iii) plasmonic applications as real operative devices in the clinical field. Future prospects in the use of nanoplasmonic sensor platforms for personalised quantification and management of biomarkers directly in body fluids will also be discussed.


Assuntos
Biomarcadores Tumorais/análise , Técnicas Biossensoriais/métodos , Ressonância de Plasmônio de Superfície/métodos , Animais , Técnicas Biossensoriais/instrumentação , Linhagem Celular , Diagnóstico , Humanos , Nanopartículas/química , Células Neoplásicas Circulantes , Ressonância de Plasmônio de Superfície/instrumentação
16.
Biosens Bioelectron ; 146: 111736, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31586762

RESUMO

Knowledge on host-pathogen interactions contributes to the development of approaches to alleviate infectious disease. In this work, we developed a surface plasmon resonance (SPR) based method for investigating bacteria/mucins interactions. Furthermore, we investigated adhesion of three pathogens, Aeromonas salmonicida, Aeromonas hydrophila and Vibrio harveyi, to Atlantic salmon mucins isolated from different epithelial sites, using SPR and microtiter-based binding assays. We demonstrated that performing bacterial binding assays to mucins using SPR is feasible and has advantages over microtiter-based binding assays, especially under flow conditions. The fluid flow in the SPR is linear and continuous and SPR enables real-time reading of mucin-bacterial bonds, which provides an in vivo-like setup for analysis of bacterial binding to mucins. The variation between technical replicates was smaller using SPR detection compared to the adenosine 5'-triphosphate (ATP) bioluminescence assay in microtiter plates. Furthermore, we demonstrated that the effect of flow on pathogen-mucin interaction is significant and that bacterial adhesion differ non-linearly with flow rates and depend on the epithelial source of the mucin.


Assuntos
Infecções Bacterianas/veterinária , Doenças dos Peixes/microbiologia , Proteínas de Peixes/metabolismo , Mucinas/metabolismo , Salmo salar/microbiologia , Animais , Infecções Bacterianas/metabolismo , Doenças dos Peixes/metabolismo , Ligação Proteica , Salmo salar/metabolismo , Ressonância de Plasmônio de Superfície/métodos
17.
Biosens Bioelectron ; 146: 111738, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31600626

RESUMO

In this paper, we have investigated multi-channel switching of light incidence in multiple directions to improve image clarity in surface plasmon microscopy (SPM) for robust and consistent imaging performance regardless of the pattern geometry and shape. Multi-channel light switching in SPM allows significant reduction of adverse scattering effects by surface plasmon (SP). For proof of concept, an eight-channel spatially switched SPM (ssSPM) system has been set up. The results with reference objects including square arrays and Siemens stars experimentally confirm much improved images with ssSPM by reducing the artifacts of SP scattering significantly. On a quantitative basis, contrast analysis preformed with square arrays shows image contrast enhanced by more than three times over conventional SPM. Three image reconstruction algorithms were evaluated for optimal image acquisition. It is suggested that averaging combined with minimum-filtering produces the highest resolution. ssSPM was applied to label-free imaging of primary neuron cultures and shown to present enhanced images with clarity far better than conventional SPM.


Assuntos
Microscopia/instrumentação , Neurônios/ultraestrutura , Imagem Óptica/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação , Animais , Desenho de Equipamento , Humanos , Processamento de Imagem Assistida por Computador/instrumentação , Processamento de Imagem Assistida por Computador/métodos , Luz , Microscopia/métodos , Neurônios/citologia , Imagem Óptica/métodos , Ressonância de Plasmônio de Superfície/métodos
18.
Mikrochim Acta ; 186(11): 713, 2019 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-31650278

RESUMO

Inspired by the increasing use of plasmonic gold and silver nanoplates as probes for diverse analytes, the research community often questions which metal nanoplates should be chosen for a given application. A comparative study was performed on the performance and physicochemical properties of three types of metal nanoplates for use in plasmonic detection of Hg(II) ion. Specifically, gold, silver and Ag@Au nanoplates were studied. The established amalgamation method integrated into a detection scheme using nanoplates affords a unique yet straightforward signaling and extraction route for selective recognition of Hg(II) ion. Upon transformation of Hg(II) ion to metallic mercury, nanoplate amalgamation takes place instantly. This reshapes both the morphology and the optical characteristics of nanoplates. It is found that gold and Ag@Au nanoplates enable highly selective quantitation of Hg(II) ion by using a DNA oligomer consisting of poly-deoxycytidine (poly(C)) as a masking agent against Ag(I) ion. The silver nanoplates, in turn, display the best sensitivity owing to the chemical instability. The induced surface plasmonic shifts (of up to 250 nm and color changes from red to green) allows for determination of Hg(II) over a wide range and with a limit of detection of ~10 nM. It is recommended that the gold and Ag@Au nanoplates are used in relatively complex systems, while silver nanoplates are suited for simple matrices. Graphic abstract The amalgamation process integrated with metal (e.g., Au, Ag and Ag@Au) nanoplates affords plasmonic detection of Hg(II) ion with the aid of a poly(c) DNA sequence as the masking agent for Ag(I) ion.


Assuntos
DNA/química , Ouro/química , Mercúrio/análise , Nanopartículas Metálicas/química , Prata/química , Ácido Ascórbico/química , Colorimetria/métodos , Água Potável/análise , Limite de Detecção , Mercúrio/química , Oxirredução , Ressonância de Plasmônio de Superfície/métodos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química
19.
Analyst ; 144(19): 5717-5723, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31482883

RESUMO

An innovative visible light-driven photoelectrochemical (PEC) immunosensing system was reasonably established for the sensitive detection of prostate-specific antigen (PSA) by using perovskite metal oxide@gold nanoparticle heterostructures (BaTiO3/Au) as the photoactive materials. When plasmonic Au nanoparticles were directly decorated on BaTiO3, a several times surface plasmon resonance (SPR) enhancement of photocurrent density was induced via the injection of hot electrons from visible light-excited Au nanoparticles into the conduction band of BaTiO3, and the combination of BaTiO3 and Au nanoparticles was employed as a promising platform for developing a photoelectrochemical bioanalysis. As a proof of concept, PSA had been detected by the BaTiO3/Au nanocomposite-based PEC sensor. To design such an immunoassay protocol, a monoclonal anti-PSA capture antibody (cAb)-coated microplate and glucose oxidase/polyclonal anti-PSA detection antibody-modified gold nanoparticles (GOx-Au NP-dAb) were used as the immunoreaction platform and signal probe, respectively. Upon the addition of target PSA, a sandwiched immunocomplex was formed accompanying the immuno-recognition between the antigen and antibody, and then the carried GOx could oxidize glucose to produce H2O2. The photocurrent of the BaTiO3/Au nanocomposite-functionalized electrode amplified with increasing H2O2 concentration since H2O2 is considered as a good hole scavenger. On the basis of the above-mentioned mechanisms and the optimized conditions, the assembled PEC immunosensor was linear with the logarithm of the PSA concentration in the range of 0.01-40 ng mL-1 with a detection limit of 4.2 pg mL-1. It afforded rapid response, good precision, and high stability and specificity, implying its great promise in photoelectrochemical immunoassays. More generally, this system sets up an ideal PEC immunosensing system based on the BaTiO3/Au nanocomposites and represents an innovative and low-cost "signal-on" assay scheme for the practical quantitative screening of low-abundance proteins.


Assuntos
Compostos de Bário/química , Ouro/química , Calicreínas/sangue , Nanopartículas Metálicas/química , Antígeno Prostático Específico/sangue , Titânio/química , Anticorpos Monoclonais/imunologia , Compostos de Bário/efeitos da radiação , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Glucose/análise , Glucose Oxidase/química , Ouro/efeitos da radiação , Humanos , Peróxido de Hidrogênio/química , Imunoensaio/métodos , Calicreínas/imunologia , Luz , Limite de Detecção , Nanopartículas Metálicas/efeitos da radiação , Nanocompostos/química , Nanocompostos/efeitos da radiação , Processos Fotoquímicos , Estudo de Prova de Conceito , Antígeno Prostático Específico/imunologia , Ressonância de Plasmônio de Superfície/métodos , Titânio/efeitos da radiação
20.
Biophys Chem ; 254: 106262, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31514114

RESUMO

The application of nanotechnologies to address biomedical questions is a key strategy for innovation in biomedical research. Among others, a key point consists in the availability of nanotechnologies for monitoring cellular processes in a real-time and label-free approach. Here, we focused on a grating-coupled Surface Plasmon Resonance (GC-SPR) sensor exploiting phase interrogation. This sensor can be integrated in a microfluidic chamber that ensures cell viability and avoids cell stress. We report the calibration of the sensor response as a function of cell number and its application to monitor cell adhesion kinetics as well as cell response to an external stimulus. Our results show that GC-SPR sensors can offer a valuable alternative to prism-coupled or imaging SPR devices, amenable for microfluidic implementation.


Assuntos
Dispositivos Lab-On-A-Chip , Ressonância de Plasmônio de Superfície/métodos , Adesão Celular , Linhagem Celular Tumoral , Sobrevivência Celular , Humanos , Microscopia de Fluorescência por Excitação Multifotônica , Nanoestruturas/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA