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1.
Biosens Bioelectron ; 169: 112578, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32911317

RESUMO

The ongoing global pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to active research in its associated diagnostics and medical treatments. While quantitative reverse transcription polymerase chain reaction (qRT-PCR) is the most reliable method to detect viral genes of SARS-CoV-2, serological tests for specific antiviral antibodies are also important as they identify false negative qRT-PCR responses, track how effectively the patient's immune system is fighting the infection, and are potentially helpful for plasma transfusion therapies. In this work, based on the principle of localized surface plasmon resonance (LSPR), we develop an opto-microfluidic sensing platform with gold nanospikes, fabricated by electrodeposition, to detect the presence and amount of antibodies specific to the SARS-CoV-2 spike protein in 1µL of human plasma diluted in 1mL of buffer solution, within ∼30min. The target antibody concentration can be correlated with the LSPR wavelength peak shift of gold nanospikes caused by the local refractive index change due to the antigen-antibody binding. This label-free microfluidic platform achieves a limit of detection of ∼0.08ng/mL (∼0.5pM), falling under the clinical relevant concentration range. We demonstrate that our opto-microfluidic platform offers a promising point-of-care testing tool to complement standard serological assays and make SARS-CoV-2 quantitative diagnostics easier, cheaper, and faster.


Assuntos
Anticorpos Antivirais/sangue , Betacoronavirus/imunologia , Infecções por Coronavirus/sangue , Nanoestruturas/química , Pneumonia Viral/sangue , Glicoproteína da Espícula de Coronavírus/imunologia , Ressonância de Plasmônio de Superfície/instrumentação , Anticorpos Antivirais/imunologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Desenho de Equipamento , Ouro/química , Humanos , Dispositivos Lab-On-A-Chip , Limite de Detecção , Nanoestruturas/ultraestrutura , Pandemias , Pneumonia Viral/imunologia , Pneumonia Viral/virologia
2.
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
3.
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
4.
Food Chem ; 332: 127346, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32619938

RESUMO

Fiber optic surface plasmon resonance (SPR) sensor utilizing silver (Ag) and Ag-graphene oxide (GO) is designed and developed for the detection of adulteration of glucose and fructose in pure honey. The concentration range of the two adulterants in pure honey is varied from 4% to 20% with a step change of 4%. The experiments were performed with two different fiber optic probes viz. Probe 1 and Probe 2. Probe 1 is fabricated by coating 50 nm Ag film on unclad optical fiber portion and Probe 2 is fabricated by modifying Ag film with GO for sensitivity improvement. The study confirms that using GO modified fiber optic probe, the sensitivity is enhanced to 24% and 37% for glucose and fructose adulterated honey samples respectively. The technique presented in this study is easy, rapid, label free and shows high prospective for the detection of adulterants in pure honey.


Assuntos
Grafite/química , Mel/análise , Fibras Ópticas , Prata/química , Ressonância de Plasmônio de Superfície/instrumentação
5.
ACS Nano ; 14(5): 5268-5277, 2020 May 26.
Artigo em Inglês | MEDLINE | ID: covidwho-46728

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
6.
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
7.
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
8.
Sensors (Basel) ; 20(2)2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31963277

RESUMO

The development of sensitive methods for in situ detection of biomarkers is a real challenge to bring medical diagnosis a step forward. The proof-of-concept of a remote multiplexed biomolecular interaction detection through a plasmonic optical fiber bundle is demonstrated here. The strategy relies on a fiber optic biosensor designed from a 300 µm diameter bundle composed of 6000 individual optical fibers. When appropriately etched and metallized, each optical fiber exhibits specific plasmonic properties. The surface plasmon resonance phenomenon occurring at the surface of each fiber enables to measure biomolecular interactions, through the changes of the retro-reflected light intensity due to light/plasmon coupling variations. The functionalization of the microstructured bundle by multiple protein probes was performed using new polymeric 3D-printed microcantilevers. Such soft cantilevers allow for immobilizing the probes in micro spots, without damaging the optical microstructures nor the gold layer. We show here the potential of this device to perform the multiplexed detection of two different antibodies with limits of detection down to a few tenths of nanomoles per liter. This tool, adapted for multiparametric, real-time, and label free monitoring is minimally invasive and could then provide a useful platform for in vivo targeted molecular analysis.


Assuntos
Técnicas Biossensoriais/métodos , Fibras Ópticas , Ressonância de Plasmônio de Superfície/métodos , Animais , Anticorpos/análise , Técnicas Biossensoriais/instrumentação , Desenho de Equipamento , Ouro/química , Limite de Detecção , Ratos , Ressonância de Plasmônio de Superfície/instrumentação , Propriedades de Superfície
9.
Nanoscale ; 12(4): 2479-2491, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31916549

RESUMO

Chiral nanohole array (CNA) films are fabricated by a simple and efficient shadow sphere lithography (SSL) method and achieve label-free enantiodiscrimination of biomolecules and drug molecules at the picogram level. The intrinsic mirror symmetry of the structure is broken by three subsequent depositions onto non-close packed nanosphere monolayers with different polar and azimuthal angles. Giant chiro-optical responses with a transmission as high as 45%, a chirality of 21°µm-1, and a g-factor of 0.17, respectively, are generated, which are among the largest values that have been reported in the literature. Such properties are due to the local rotating current density generated by a surface plasmon polariton as well as a strong local rotating field produced by localized surface plasmon resonance, which leads to the excitation of substantial local superchiral fields. The 70 nm-thick CNAs can achieve label-free enantiodiscrimination of biomolecules and drug molecules at the picogram level as demonstrated experimentally. All these advantages make the CNAs ready for low-cost, high-performance, and ultracompact polarization converters and label-free chiral sensors.


Assuntos
Nanoestruturas/química , Nanotecnologia/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação , Nanopartículas Metálicas/química , Impressão Molecular , Nanosferas/química , Rotação Ocular , Prata/química , Propriedades de Superfície
10.
Food Chem ; 307: 125530, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31639579

RESUMO

The Surface Plasmon resonance (SPR) based label-free detection of small targeted molecules is a great challenge and require substantial signal amplification for the accurate and precise quantification. The incorporation of noble metal nanoparticles (NPs) like gold (Au) NPs for the fabrication of SPR biosensor has shown remarkable impact both for anchoring the signal amplification and generate plasmonic resonant coupling between NPs and chip surface. In this work, we present comparative studies related to the fabrication of self-assembled monolayer (SAM) and the influence of AuNPs on Au chip for Aflatoxin B1 (AFB1) detection using SPRi apparatus. The SAM Au chip was sequentially modified by EDC-NHS crosslinkers, grafting of protein-A and finally interaction with anti-AFB1 antibodies. Similar multilayer chip surface was prepared using functionalized lipoic acid AuNPs deposited on SAM Au chips followed by in situ activation of functional groups using EDC-NHS crosslinkers, grafting of protein-A and immobilization of anti-AFB1 antibodies. This multilayer functionalized AuNPs modified Au chip was successfully utilized for AFB1 detection ranging from 0.01 to 50 nM with a limit of detection of 0.003 nM. When compared to bare self-assembled Au chip which was shown to exhibit a limit of detection of 0.19 nM and a linear detection ranging from 1 to 50 nM, the AuNPs modified Au chip was proven to clearly be a better analytical tool. Finally, validation of the proposed biosensor was evaluated by spiked wheat samples and average recoveries (93 and 90.1%) were found to be acceptable.


Assuntos
Aflatoxina B1/análise , Técnicas Biossensoriais/instrumentação , Nanopartículas Metálicas/química , Microfluídica , Ressonância de Plasmônio de Superfície/instrumentação , Anticorpos , Ouro , Limite de Detecção
11.
Mikrochim Acta ; 187(1): 8, 2019 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-31797057

RESUMO

A surface plasmon resonance study was carried out for the identification and determination of the organophosphate pesticide fenitrothion via an optical fiber sensor. A thin layer of silver was deposited on the unclad core of silica optical fiber for plasmon generation. This was followed by the deposition of a sensing surface comprising a layer of tantalum(V) oxide nanoparticles sequestered in a nano-scaled matrix of reduced graphene oxide. The sensing mechanism is due to the interaction of fenitrothion with the silver film which leads to a change in refractive index.. Characterized by a wavelength interrogation scheme, the fiber-optic sensor exhibited a red shift equalling 56 nm corresponding to fenitrothion concentration in the range 0.25-4 µM including the blank solution. The spectral sensitivity is 24 nm µM-1, the limit of detection is 38 nM, and the response time is as short as 23 s. The sensor is selective, repeatable and works at ambient temperature. Graphical abstractSchematic representation of the sensing mechanism of an SPR based fiber-optic fenitrothion sensor utilizing modification in refractive index of sensing surface comprising of tantalum(V) oxide (Ta2O5) nanoparticles embedded in reduced graphene oxide (rGO) caused by interaction with fenitrothion entities.


Assuntos
Fenitrotion/análise , Grafite/química , Nanotecnologia/instrumentação , Fibras Ópticas , Óxidos/química , Praguicidas/análise , Ressonância de Plasmônio de Superfície/instrumentação , Tantálio/química , Calibragem , Fenitrotion/química , Limite de Detecção , Oxirredução , Praguicidas/química , Fatores de Tempo
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.
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
14.
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
15.
Analyst ; 144(19): 5700-5705, 2019 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-31486454

RESUMO

To analyze multiple analytes in trace samples, low-dosage and high efficiency are crucial in many common cases. Herein, we developed a facile method using a single-channel surface plasmon resonance (SPR)-based biosensor for the simultaneous detection of gentamicin (GEN) and melamine (MEL) in milk and serum with only one sample injection. Based on a sandwich immunoassay, non-interfering antibodies against GEN from mouse (AbGEN) and against MEL from rabbit (AbMEL) were chosen to capture the analytes. Secondary antibodies against mouse (AbM) and rabbit (AbR) were used to bind with AbGEN and AbMEL to determine the concentrations of GEN and MEL on a single channel of an SPR sensor. All of the detection process could be done in 10 min with 50 µL of sample injection. According to the response shifts of AbM and AbR, two standard curves for GEN and MEL were obtained successively, with the limit of detection (LOD) values at 4.4 ng mL-1 and 1.3 ng mL-1, respectively. Moreover, the feasibility was determined by spiking milk and serum samples with GEN and MEL, with recoveries in the range of 81.6%-118.0%. Importantly, the analytes can be substituted by others for much more applications. This method is also expected to multiply the detection efficiency of multi-channel SPR biosensors with low-dosage samples in the future.


Assuntos
Técnicas Biossensoriais/métodos , Imunoensaio/métodos , Ressonância de Plasmônio de Superfície/métodos , Animais , Anticorpos/imunologia , Técnicas Biossensoriais/instrumentação , Gentamicinas/análise , Gentamicinas/imunologia , Humanos , Limite de Detecção , Camundongos , Leite/química , Coelhos , Reprodutibilidade dos Testes , Soro , Ressonância de Plasmônio de Superfície/instrumentação , Triazinas/análise
16.
Biosens Bioelectron ; 142: 111568, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31442945

RESUMO

A label-free, non-dispruptive, and real-time analytical device to monitor the dynamic features of biomolecules and their interactions with neighboring molecules is an essential prerequisite for biochip- and diagonostic assays. To explore one of the central questions on the lipid-lipid interactions in the course of the liquid-ordered (lo) domain formation, called rafts, we developed a method of reconstituting continuous but spatially heterogeneous lipid membrane platforms with molayer-bilayer juntions (MBJs) that enable to form the lo domains in a spatiotemporally controlled manner. This allows us to detect the time-lapse dynamics of the lipid-lipid interactions during raft formation and resultant membrane phase changes together with the raft-associated receptor-ligand binding through the surface plasmon resonance (SPR). For cross-validation, using epifluorescence microscopy, we demonstrated the underlying mechanisms for raft formations that the infiltration of cholesterols into the sphingolipid-enriched domains plays a crucial roles in the membrane phase-separation. Our membrane platform, being capable of monitoring dynamic interactions among lipids and performing the systematic optical analysis, will unveil physiological roles of cholesterols in a variety of biological events.


Assuntos
Colesterol/metabolismo , Dispositivos Lab-On-A-Chip , Bicamadas Lipídicas/metabolismo , Microdomínios da Membrana/metabolismo , Ressonância de Plasmônio de Superfície/instrumentação , Animais , Colesterol/análise , Desenho de Equipamento , Humanos , Cinética , Bicamadas Lipídicas/análise , Microdomínios da Membrana/química , Modelos Moleculares , Transição de Fase , Ligação Proteica , Ressonância de Plasmônio de Superfície/métodos
17.
Biosens Bioelectron ; 142: 111545, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31376712

RESUMO

We propose a spectral contrast method to map the transmission images of surface plasmon resonance (SPR) in metallic nanostructures. Comparing the intensities between two neighboring wavelength bands near the SPR wavelength, the signal-to-noise ratio for biosensing applications obtained using the proposed method is found to be ten times higher than that obtained by conventional intensity analysis and 1.6 times better than that obtained by peak-wavelength fitting. The dynamic range and linearity of the refractive index are comparable to the peak-wavelength shift measurement. Based on the detection method, a spectral modulation system for the optical microscope is developed, combined with a gold-capped nanowire array, to measure the biointeractions in microfluidic devices. The experimental results show that the proposed method obtained multiple detections with a detection limit of 1.04 × 10-5 refractive index units. Two types of analysis methods for SPR images are used to study the protein-antibody interactions. The region-of-interest analysis supports multiplexing detections in a compact microfluidic sensor. The effective pixel analysis eliminates low-response pixels and enhances the signal-to-noise ratios for sensitive label-free detection.


Assuntos
Ouro/química , Nanoestruturas/química , Imagem Óptica/métodos , Ressonância de Plasmônio de Superfície/métodos , Desenho de Equipamento , Glucose/análise , Nanofios/química , Imagem Óptica/instrumentação , Refratometria , Ressonância de Plasmônio de Superfície/instrumentação
18.
PLoS One ; 14(8): e0220578, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31369601

RESUMO

Grating-coupled surface plasmon field-enhanced fluorescence spectroscopy (GC-SPFS) with optical bound/free (B/F) separation technique was developed by employing a highly directional fluorescence with polarization of surface plasmon-coupled emission (SPCE) to realize highly sensitive immunoassay regardless of the ligand affinity. A highly sensitive immunoassay system with GC-SPFS was constructed using a plastic sensor chip reproducibly fabricated in-house by nanoimprinting and applied to the quantitative detection of an anti-lysozyme single-domain antibody (sdAb), to compare conventional washing B/F separation with optical B/F separation. Differences in the affinity of the anti-lysozyme sdAb, induced by artificial mutation of only one amino acid residue in the variable domain were attributed to higher sensitivity than that of the conventional Biacore surface plasmon resonance (SPR) system. The detection limit (LOD; means of six replicates of the zero standard plus three standard deviations) of the GC-SPFS immunoassay with optical B/F separation, was estimated to be 1.2 ng/ml with the low-affinity ligand (mutant sdAb Y52A: KD level was of the order of 10-7 ~ 10-6 M) and was clearly improved as compared to that (LOD: 9.4 ng/ml) obtained with the conventional washing B/F separation. These results indicate that GC-SPFS with the optical B/F separation technique offers opportunities to re-evaluate low-affinity biomaterials that are neither fully utilized nor widespread, and could facilitate the creation of novel and innovative methods in drug and diagnostic development.


Assuntos
Espectrometria de Fluorescência/métodos , Ressonância de Plasmônio de Superfície/métodos , Imunoensaio/instrumentação , Imunoensaio/métodos , Limite de Detecção , Muramidase/imunologia , Anticorpos de Domínio Único/análise , Anticorpos de Domínio Único/imunologia , Espectrometria de Fluorescência/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação
19.
J Pharm Biomed Anal ; 176: 112822, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31454662

RESUMO

The development of surface plasmon resonance (SPR) based immunosensor for thrombin detection was aimed. For this purpose, 3,3' Dithiodipropionic acid di (N-hydroxysuccinimide ester) (DSP):6-mercapto-1-hexanol (MCH) mixed self-assembled monolayers (mSAMs) were formed on gold surfaces for immobilization of anti-thrombin antibody. The performance of the immunosensor was determined against the target protein thrombin at various concentrations using flow cell coupled SPR. The linear detection range of the immunosensor was 30.0-100.0 nM with an R2 value of 0,992. Limit of Detection (LOD) and Limit of Quantification (LOQ) were determined to be 6.0 nM and 30.0 nM, respectively. The selectivity of the immunosensor was tested against a non-target model protein, human serum albumin (HSA) and the obtained ΔRU value was found to be below the ΔRU value corresponding to the LOQ concentration for thrombin. The immunosensor's capability to detect thrombin in diluted complex serum matrix was also tested and the obtained ΔRU value (159 ±â€¯16) was compared with ΔRU value obtained for thrombin detection in PBS solution (137 ±â€¯19). Based on the results, it was shown that DSP:MCH interface is a promising immobilization platform for binding biological recognition elements for the development of biosensors.


Assuntos
Técnicas Biossensoriais/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação , Trombina/isolamento & purificação , Anticorpos/imunologia , Humanos , Limite de Detecção , Trombina/imunologia
20.
Biosens Bioelectron ; 142: 111565, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31404878

RESUMO

We investigated sequence-specific and simultaneous microRNA (miRNA) detections by surface plasmon resonance (SPR) imaging measurements on SPR chips possessing an Au spot array modified with probe DNAs based on a miRNA-detection-selective SPR signal amplification method. MiRNAs were detected with the detection limit of the attomole level by SPR imaging measurements for different miRNA concentrations on a single chip. SPR signals were enhanced based on a combination process of sequence-specific hybridization of the miRNA to the probe DNAs, extension reaction of polyadenine (poly(A)) tails by poly(A) polymerase, binding of a ternary complex of T30-biotin/horseradish peroxidase (HRP)-biotin/streptavidin to the poly(A) tails, and the oxidation reaction of tetramethylbenzidine (TMB) on the HRP by providing a blue precipitate on the surface. This process sequence-specifically and dramatically amplified the SPR signals. This is a simple, cost-effective, and feasible signal amplification method based on the organic compound TMB instead of metal nanoparticles.


Assuntos
MicroRNAs/análise , Ressonância de Plasmônio de Superfície/instrumentação , Benzidinas/química , Sondas de DNA/química , Desenho de Equipamento , Humanos , Limite de Detecção , Hibridização de Ácido Nucleico , Análise de Sequência com Séries de Oligonucleotídeos/instrumentação
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