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1.
Methods Mol Biol ; 2263: 369-379, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33877608

RESUMO

The recognition of specific DNA sequences by proteins is crucial to fundamental biological processes such as DNA replication, transcription, and gene regulation. The technique of surface plasmon resonance (SPR) is ideally suited for the measurement of these interactions because it is quantitative, simple to implement, reproducible, can be automated, and requires very little sample. This typically involves the direct capture of biotinylated DNA to a streptavidin (SA) chip before flowing over the protein of interest and monitoring the interaction. However, once the DNA has been immobilized on the chip, it cannot be removed without damaging the chip surface. Moreover, if the protein-DNA interaction is strong, then it may not be possible to remove the protein from the DNA without damaging the chip surface. Given that the chips are costly, this will limit the number of samples that can be tested. Therefore, we have developed a Reusable DNA Capture Technology, or ReDCaT chip, that enables a single streptavidin chip to be used multiple times making the technique simple, quick, and cost effective. The general steps to prepare the ReDCaT chip, run a simple binding experiment, and analysis of data will be described in detail. Some additional applications will also be introduced.


Assuntos
Proteínas de Ligação a DNA/metabolismo , DNA/metabolismo , Ressonância de Plasmônio de Superfície/instrumentação , Sítios de Ligação , Biotina/química , DNA/química , Proteínas de Ligação a DNA/química , Análise Serial de Proteínas/instrumentação , Estreptavidina/química
2.
Anal Bioanal Chem ; 413(12): 3329-3337, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33712917

RESUMO

A new biosensing method is presented to detect gene mutation by integrating the MutS protein from bacteria with a fiber optic particle plasmon resonance (FOPPR) sensing system. In this method, the MutS protein is conjugated with gold nanoparticles (AuNPs) deposited on an optical fiber core surface. The target double-stranded DNA containing an A and C mismatched base pair in a sample can be captured by the MutS protein, causing increased absorption of green light launching into the fiber and hence a decrease in transmitted light intensity through the fiber. As the signal change is enhanced through consecutive total internal reflections along the fiber, the limit of detection for an AC mismatch heteroduplex DNA can be as low as 0.49 nM. Because a microfluidic chip is used to contain the optical fiber, the narrow channel width allows an analysis time as short as 15 min. Furthermore, the label-free and real-time nature of the FOPPR sensing system enables determination of binding affinity and kinetics between MutS and single-base mismatched DNA. The method has been validated using a heterozygous PCR sample from a patient to determine the allelic fraction. The obtained allelic fraction of 0.474 reasonably agrees with the expected allelic fraction of 0.5. Therefore, the MutS-functionalized FOPPR sensor may potentially provide a convenient quantitative tool to detect single nucleotide polymorphisms in biological samples with a short analysis time at the point-of-care sites.


Assuntos
Técnicas Biossensoriais/instrumentação , Proteínas MutS/química , Fibras Ópticas , Polimorfismo de Nucleotídeo Único , Ressonância de Plasmônio de Superfície/instrumentação , DNA de Cadeia Simples/genética , DNA de Cadeia Simples/normas , Ouro/química , Humanos , Limite de Detecção , Nanopartículas Metálicas/química , Mutação Puntual , Padrões de Referência , Talassemia beta/genética
3.
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
4.
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 , COVID-19/diagnóstico , COVID-19/virologia , Humanos , Limite de Detecção , Óptica e Fotônica , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/metabolismo , Ressonância de Plasmônio de Superfície/instrumentação , Temperatura
5.
Opt Express ; 28(26): 39770-39780, 2020 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-33379519

RESUMO

A multi-diffractive nanostructure is reported for the resonant excitation of surface plasmons that are cross-coupled through a thin metallic film. It consists of two superimposed periodic corrugations that allow diffraction excitation of surface plasmons on the inner side of a thin metal film and their subsequent phase matching with counterpropagating surface plasmons travelling to the opposite direction on its other side. This interaction leads to establishing of a set of cross-coupled Bragg-scattered surface plasmon modes that exhibit an electromagnetic field localized on both metal film interfaces. The reported structure is attractive for surface plasmon resonance biosensor applications, where direct optical probing can be done through the substrate without the need of optical matching to a high refractive index prism. In addition, it can be prepared by mass production - compatible means with UV-nanoimprint lithography and its biosensing performance characteristics are demonstrated by refractometric and biomolecular affinity binding studies.


Assuntos
Técnicas Biossensoriais/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação , Algoritmos , Desenho de Equipamento , Análise de Falha de Equipamento , Modelos Teóricos , Refratometria/instrumentação
6.
Int J Nanomedicine ; 15: 8131-8149, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33144830

RESUMO

Background: Advanced medical detection technology requires high sensitivity and accuracy to increase the disease detection rate. We showed that carboxyl-functionalized graphene oxide (carboxyl-GO) biosensing materials are capable of accurate detection. Methods: We developed a carboxylated GO-based surface plasmon resonance (SPR) aptasensor suitable for screening Down's syndrome in clinical serum. This biosensing material could rapidly and accurately detect hCG protein with a low concentration to identify fetal Down's syndrome. The developed carboxyl-GO-based SPR aptasensor showed excellent sensitivity and limit of detection without the use of antibodies and without any specific preference. Results: hCG protein detection limits of 1 pM in buffer samples and 1.9 pM in clinical serum samples were achieved. The results showed that the carboxyl-GO-based chip could detect hCG well below the normal physiological level of serum protein (5.0 mIU/mL). High affinity, sensitivity, and better detection limit were obtained in the range of 1.9 pM to 135 pM. The results showed a 5k-fold dilution factor, and that an SPR angle shift of more than 20 millidegrees (mo) was associated with a significant risk of fetal Down's syndrome compared to normal pregnant women. The results clearly showed that the detection of hCG protein in serum samples from pregnant women at 12-19 weeks could be used to screen Down's syndrome with high selectivity and sensitivity. Conclusion: Our findings suggest the potential application of carboxyl-GO film in proof-of-concept studies for serum assays as a new type of SPR material. In addition, peptide and carboxyl-GO films may be conducive to the development of future point of care testing and rapid diagnostic devices for other diseases such as cancer.


Assuntos
Gonadotropina Coriônica/sangue , Síndrome de Down/diagnóstico , Grafite/química , Diagnóstico Pré-Natal/métodos , Ressonância de Plasmônio de Superfície/métodos , Adulto , Aptâmeros de Peptídeos/química , Biomarcadores/sangue , Tampões (Química) , Síndrome de Down/sangue , Feminino , Humanos , Limite de Detecção , Peptídeos , Gravidez , Sensibilidade e Especificidade , Espectroscopia de Infravermelho com Transformada de Fourier , Ressonância de Plasmônio de Superfície/instrumentação
7.
Anal Chem ; 92(22): 14939-14946, 2020 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-33112611

RESUMO

The development of a versatile sensing strategy for the damage-free characterization of cultured cells is of great importance for both fundamental biological research and industrial applications. Here, we present a pattern-recognition-based cell-sensing approach using a multichannel surface plasmon resonance (SPR) chip. The chip, in which five cysteine derivatives with different structures are immobilized on Au films, is capable of generating five unique SPR sensorgrams for the cell-secreted molecules that are contained in cell culture media. An automatic statistical program was built to acquire kinetic parameters from the SPR sensorgrams and to select optimal parameters as "pattern information" for subsequent multivariate analysis. Our system rapidly (∼10 min) provides the complex information by merely depositing a small amount of cell culture media (∼25 µL) onto the chip, and the amount of information obtained is comparable to that furnished by a combination of conventional laborious biochemical assays. This noninvasive pattern-recognition-based cell-sensing approach could potentially be employed as a versatile tool for characterizing cells.


Assuntos
Dispositivos Lab-On-A-Chip , Ressonância de Plasmônio de Superfície/instrumentação , Linhagem Celular Tumoral , Cisteína/química , Ouro/química , Humanos , Cinética , Análise de Sequência com Séries de Oligonucleotídeos
8.
Molecules ; 25(20)2020 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-33065967

RESUMO

We investigate the plasmonic behavior of a fractal photonic crystal fiber, with Sierpinski-like circular cross-section, and its potential applications for refractive index sensing and multiband polarization filters. Numerical results were obtained using the finite element method through the commercial software COMSOL Multiphysics®. A set of 34 surface plasmon resonances was identified in the wavelength range from λ=630 nm to λ=1700 nm. Subsets of close resonances were noted as a consequence of similar symmetries of the surface plasmon resonance (SPR) modes. Polarization filtering capabilities are numerically shown in the telecommunication windows from the O-band to the L-band. In the case of refractive index sensing, we used the wavelength interrogation method in the wavelength range from λ=670 nm to λ=790 nm, where the system exhibited a sensitivity of S(λ)=1951.43 nm/RIU (refractive index unit). Due to the broadband capabilities of our concept, we expect that it will be useful to develop future ultra-wide band optical communication infrastructures, which are urgent to meet the ever-increasing demand for bandwidth-hungry devices.


Assuntos
Óptica e Fotônica/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação , Desenho de Equipamento , Análise de Elementos Finitos , Fractais , Refratometria , Sensibilidade e Especificidade , Ressonância de Plasmônio de Superfície/métodos
9.
Molecules ; 25(20)2020 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-33066088

RESUMO

Nano-islands are entities (droplets or other shapes) that are formed by spontaneous dewetting (agglomeration, in the early literature) of thin and very thin metallic (especially gold) films on a substrate, done by post-deposition heating or by using other sources of energy. In addition to thermally generated nano-islands, more recently, nanoparticle films have also been dewetted, in order to form nano-islands. The localized surface plasmon resonance (LSPR) band of gold nano-islands was found to be sensitive to changes in the surrounding environment, making it a suitable platform for sensing and biosensing applications. In this review, we revisit the development of the concept of nano-island(s), the thermodynamics of dewetting of thin metal films, and the effect of the substrate on the morphology and optical properties of nano-islands. A special emphasis is made on nanoparticle films and their applications to biosensing, with ample examples from the authors' work.


Assuntos
Ouro/química , Nanocompostos/química , Sistemas Automatizados de Assistência Junto ao Leito , Ressonância de Plasmônio de Superfície/instrumentação , Animais , Técnicas Biossensoriais/instrumentação , Hormônio do Crescimento/análise , Humanos , Dispositivos Lab-On-A-Chip , Leite/química , Nanotecnologia/métodos , Ressonância de Plasmônio de Superfície/métodos
10.
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 , COVID-19 , 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 , SARS-CoV-2
11.
J Agric Food Chem ; 68(46): 12927-12939, 2020 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-32816471

RESUMO

Surface plasmon resonance imaging (SPRi) has been increasingly used in the label-free detections of various biospecies, such as organic toxins, proteins, and bacteria. In combination with the well-developed microarray immunoassay, SPRi has the advantages of rapid detection in tens of minutes and multiplex detection of different targets with the same biochip. Both prism-based and prism-free configurations of SPRi have been developed for highly integrated portable immunosensors, which have shown great potential on pathogen detection and living cell imaging. This review summarizes the recent advances in immunoassay biosensing with SPRi, with special emphasis on the multiplex detections of foodborne pathogens. Additionally, various spotting techniques, surface modification protocols, and signal amplification methods have been developed to improve the specificity and sensitivity of the SPRi biochip. The challenges in multiplex detections of foodborne pathogens in real-world samples are addressed, and future perspectives of miniaturizing SPRi immunosensors with nanotechnologies are discussed.


Assuntos
Bactérias/isolamento & purificação , Doenças Transmitidas por Alimentos/microbiologia , Imunoensaio/métodos , Ressonância de Plasmônio de Superfície/métodos , Animais , Bactérias/química , Bactérias/crescimento & desenvolvimento , Microbiologia de Alimentos , Humanos , Imunoensaio/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação
12.
Anal Chem ; 92(15): 10783-10791, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32638586

RESUMO

The polymerase chain reaction (PCR) has been the gold standard molecular analysis technique for decades and has seen quite some evolution in terms of reaction components, methodology, and readout mechanisms. Nucleic acid enzymes (NAzymes) have been used to further exploit the applications of PCR, but so far the work was limited to the colorimetric G-quadruplex or fluorescent substrate cleaving NAzymes. In this study, a solid-phase, fiber optic surface plasmon resonance (FO-SPR) technique is presented as an alternative readout for PCR utilizing NAzymes. First, the surface cleavage activity of DNAzyme-extended amplicons (DNAzyme-amps) is established, followed by optimization of the PCR conditions, which are required for compatibility with the FO-SPR system. Next, by integrating the complement of a 10-23 DNAzyme into the primer pair, PCR-amplified DNAzyme-amps were generated, tested, and validated on qPCR for the detection of the antimicrobial resistance gene MCR-2. Once validated, this primer concept was developed as a one-step assay, driven by PCR-amplified DNAzymes, for FO-SPR-based sensitive and specific detection. Using gold nanoparticle labeled RNA-DNA hybrid strands as substrate for the DNAzyme, PCR-amplified DNAzyme-amps generated in the presence of MCR-2 gene were monitored in real-time, which resulted in an experimental limit of detection of 4 × 105 copy numbers or 6.6 fM. In addition, the DNAzyme-based FO-PCR assay was able to discriminate between the MCR-1 and MCR-2 genes, to further prove the specificity of this assay. Henceforth, this DNAzyme-based fiber optic PCR assay provides a universally applicable, real-time system for the detection of virtually any target NA, in a specific and sensitive manner.


Assuntos
DNA Catalítico/genética , DNA Catalítico/metabolismo , Proteínas de Membrana/genética , Fibras Ópticas , Reação em Cadeia da Polimerase , Ressonância de Plasmônio de Superfície/instrumentação , Calibragem , Fatores de Tempo
13.
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
14.
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
15.
Methods Mol Biol ; 2141: 611-627, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32696380

RESUMO

Surface plasmon resonance (SPR) is an important and convenient method for measuring kinetic rate constants of given molecular interactions, equilibrium binding constants at steady state, or determinations of binding stoichiometry. In its traditional setup, SPR requires that one binding partner is tightly immobilized on the surface of a sensor chip either by direct chemical coupling to the surface-coated carboxymethylated dextran matrix or by non-covalent capture to a high-affinity binding partner that is covalently linked to the surface. The latter design of the sensor surface is highly advantageous compared to the direct chemical coupling as this setup ensures a homogeneous and specific orientation of the immobilized binding partner. This chapter provides guidelines for the design of capturing systems that generally provide high-end kinetic data suitable for determination of binding rate constants. This principle will be illustrated by the binding of synthetic peptides derived from an intrinsically disordered region of the endothelial glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 (GPIHBP1) to captured monoclonal antibodies.


Assuntos
Técnicas Biossensoriais , Proteínas Intrinsicamente Desordenadas/metabolismo , Ressonância de Plasmônio de Superfície/métodos , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Desenho de Equipamento , Cinética , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Ligação Proteica , Mapeamento de Interação de Proteínas , Receptores de Lipoproteínas , Ressonância de Plasmônio de Superfície/instrumentação
16.
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
17.
Sci Rep ; 10(1): 11154, 2020 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-32636434

RESUMO

Different lines of evidence indicate that monitoring the blood levels of therapeutic antibodies, characterized by high inter-individual variability, can help to optimize clinical decision making, improving patient outcomes and reducing costs with these expensive treatments. A surface plasmon resonance (SPR)-based immunoassay has recently been shown to allow highly reliable and robust monitoring of serum concentrations of infliximab, with significant advantages over classical ELISA. The next level of advancement would be the availability of compact and transportable SPR devices suitable for easy, fast and cheap point-of-care analysis. Here we report the data obtained with recently developed, cost-effective, optical-fibre-based SPR sensors (SPR-POF), which allow the construction of a compact miniaturized system for remote sensing. We carried out an extensive characterization of infliximab binding to an anti-infliximab antibody immobilized on the SPR-POF sensor surface. The present proof-of-principle studies demonstrate the feasibility of the proposed SPR-POF platform for the specific detection of infliximab, in both buffer and human serum, and pave the way for further technological improvements.


Assuntos
Anticorpos/sangue , Técnicas Biossensoriais/métodos , Ressonância de Plasmônio de Superfície/métodos , Anticorpos/uso terapêutico , Técnicas Biossensoriais/instrumentação , Ensaio de Imunoadsorção Enzimática , Humanos , Fibras Ópticas , Tecnologia de Sensoriamento Remoto/instrumentação , Tecnologia de Sensoriamento Remoto/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Ressonância de Plasmônio de Superfície/instrumentação
18.
Analyst ; 145(11): 3776-3800, 2020 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-32374303

RESUMO

Plasmonic sensors are ideally suited for the design of small, integrated, and portable devices that can be employed in situ for the detection of analytes relevant to environmental sciences, clinical diagnostics, infectious diseases, food, and industrial applications. To successfully deploy plasmonic sensors, scaled-down analytical devices based on surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR) must integrate optics, plasmonic materials, surface chemistry, fluidics, detectors and data processing in a functional instrument with a small footprint. The field has significantly progressed from the implementation of the various components in specifically designed prism-based instruments to the use of nanomaterials, optical fibers and smartphones to yield increasingly portable devices, which have been shown for a number of applications in the laboratory and deployed on site for environmental, biomedical/clinical, and food applications. A roadmap to deploy plasmonic sensors is provided by reviewing the current successes and by laying out the directions the field is currently taking to increase the use of field-deployed plasmonic sensors at the point-of-care, in the environment and in industries.


Assuntos
Ressonância de Plasmônio de Superfície/métodos , Animais , Bactérias/isolamento & purificação , Biomarcadores Tumorais/sangue , Biomarcadores Tumorais/urina , Linhagem Celular Tumoral , Poluentes Ambientais/análise , Contaminação de Alimentos/análise , Humanos , Smartphone , Ressonância de Plasmônio de Superfície/instrumentação
19.
Nucleosides Nucleotides Nucleic Acids ; 39(7): 1057-1072, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32397925

RESUMO

The aim of this study is to develop a methodology in which Surface Plasmon Resonance (SPR), Ellipsometer (EM) and Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry (MALDI-MS) will be used together for detection of single-strand oligodeoxynucleotides (ssODNs) targets. A selected target-ssODNs, and its complementary, the probe-ssODNs carrying a -SH end group, a spacer arm (HS-(CH2)6-(T)15, and a non-complementary ssODNs were used. Silicone based stamps with 16 regions were prepared and used for micro-contact printing (µCP) of the probe-ssODNs on the gold coated surfaces homogeneously. A modulator-spacer molecule (6-mercapto-1-hexanol) was co-immobilized to control surface probe density, to orientate the probe-ssODNs, and to eliminate the nonspecific interactions. SPR was used successfully to follow the hybridization of the target-ssODNs with the immobilized probe-ssODNs on the platform surfaces. Complete hybridizations were achieved in 100 min. It was obtained that there was a linear relationship between relative change in delta and target concentration below 1 µm. Using imaging version of ellipsometer (IEM) allowed imaging of the surfaces and supported extra datum for the SPR results. After a very simple dehybridization protocol, MALDI-MS analysis allowed detection of the target-ssODNs hybridized on the sensor/array platforms.


Assuntos
Técnicas Biossensoriais , DNA de Cadeia Simples/análise , Hibridização de Ácido Nucleico , Ressonância de Plasmônio de Superfície , Técnicas Biossensoriais/instrumentação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação
20.
Anal Bioanal Chem ; 412(14): 3317-3349, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32313998

RESUMO

Direct optical detection has proven to be a highly interesting tool in biomolecular interaction analysis to be used in drug discovery, ligand/receptor interactions, environmental analysis, clinical diagnostics, screening of large data volumes in immunology, cancer therapy, or personalized medicine. In this review, the fundamental optical principles and applications are reviewed. Devices are based on concepts such as refractometry, evanescent field, waveguides modes, reflectometry, resonance and/or interference. They are realized in ring resonators; prism couplers; surface plasmon resonance; resonant mirror; Bragg grating; grating couplers; photonic crystals, Mach-Zehnder, Young, Hartman interferometers; backscattering; ellipsometry; or reflectance interferometry. The physical theories of various optical principles have already been reviewed in detail elsewhere and are therefore only cited. This review provides an overall survey on the application of these methods in direct optical biosensing. The "historical" development of the main principles is given to understand the various, and sometimes only slightly modified variations published as "new" methods or the use of a new acronym and commercialization by different companies. Improvement of optics is only one way to increase the quality of biosensors. Additional essential aspects are the surface modification of transducers, immobilization strategies, selection of recognition elements, the influence of non-specific interaction, selectivity, and sensitivity. Furthermore, papers use for reporting minimal amounts of detectable analyte terms such as value of mass, moles, grams, or mol/L which are difficult to compare. Both these essential aspects (i.e., biochemistry and the presentation of LOD values) can be discussed only in brief (but references are provided) in order to prevent the paper from becoming too long. The review will concentrate on a comparison of the optical methods, their application, and the resulting bioanalytical quality.


Assuntos
Técnicas Biossensoriais/instrumentação , Dispositivos Ópticos , Animais , Técnicas Biossensoriais/métodos , Desenho de Equipamento , Humanos , Interferometria/instrumentação , Interferometria/métodos , Luz , Refratometria/instrumentação , Refratometria/métodos , Ressonância de Plasmônio de Superfície/instrumentação , Ressonância de Plasmônio de Superfície/métodos , Transdutores
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