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1.
Adv Sci (Weinh) ; 9(4): e2102924, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34898053

RESUMO

The combination of 2D materials and optical biosensors has become a hot research topic in recent years. Graphene, transition metal dichalcogenides, black phosphorus, MXenes, and other 2D materials (metal oxides and degenerate semiconductors) have unique optical properties and play a unique role in the detection of different biomolecules. Through the modification of 2D materials, optical biosensor has the advantages that traditional sensors (such as electrical sensing) do not have, and the sensitivity and detection limit are greatly improved. Here, optical biosensors based on different 2D materials are reviewed. First, various detection methods of biomolecules, including surface plasmon resonance (SPR), fluorescence resonance energy transfer (FRET), and evanescent wave and properties, preparation and integration strategies of 2D material, are introduced in detail. Second, various biosensors based on 2D materials are summarized. Furthermore, the applications of these optical biosensors in biological imaging, food safety, pollution prevention/control, and biological medicine are discussed. Finally, the future development of optical biosensors is prospected. It is believed that with their in-depth research in the laboratory, optical biosensors will gradually become commercialized and improve people's quality of life in many aspects.


Assuntos
Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Transferência Ressonante de Energia de Fluorescência/instrumentação , Transferência Ressonante de Energia de Fluorescência/métodos , Ressonância de Plasmônio de Superfície/instrumentação , Ressonância de Plasmônio de Superfície/métodos , Grafite/química , Humanos , Óxidos/química , Fósforo/química , Elementos de Transição/química
2.
Appl Opt ; 59(24): 7299-7307, 2020 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-32902494

RESUMO

We present the performance enhancement of the surface plasmon resonance (SPR) sensor for deoxyribonucleic acid (DNA) hybridization employing black phosphorus (BP), silver (Ag), and silicon (Si) configurations and numerical analysis. The combination of Ag and BP demonstrates the sensitivity of 91.54°/RIU with degradation of detection accuracy (DA), quality factor (QF), and figure of merit (FOM). To enhance the DA, QF, and FOM, a novel SPR is proposed with Si, which demonstrates a DA and QF of 69 and 1061.6RIU-1, which are 8.53 and 11.04 times, and an FOM of 554.58, which is 4.47 and 5.77 times higher than both the conventional and graphene-based SPR sensors, respectively.


Assuntos
DNA/análise , Fósforo/química , Silício/química , Prata/química , Ressonância de Plasmônio de Superfície/instrumentação , Ressonância de Plasmônio de Superfície/métodos , Melhoramento Biomédico , Técnicas Biossensoriais , Desenho de Equipamento , Grafite/química , Modelos Químicos , Sensibilidade e Especificidade , Propriedades de Superfície
3.
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
4.
Biosens Bioelectron ; 122: 183-188, 2018 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-30265968

RESUMO

Colloidal metal nanoparticles (NPs) with remarkable localized surface plasmon resonance (LSPR) have found wide use as probes in sensing. The LSPR that employed as the sensing signal is strongly associated with the morphology of nanoprobes. In this work, morphological change of Au nanocage to Au@Ag nanobox and thus the LSPR evolution are well regulated by trace amount of antioxidant, where the mechanism of seed-mediated growth is used as a powerful means in this process. Based on the linear relationship between morphology-induced LSPR evolution and the concentration of antioxidant, a simple, reliable and highly sensitive colorimetric method is developed for antioxidant detection. The detectable range of this method is 0.01-5 µM and 2-20 µM when a UV-vis spectrophotometer and a smartphone are employed as an analyzer, respectively. It has also been successfully applied in the detection of total antioxidants in green tea. This work provides new insights into developing sensitive LSPR-based sensors through precisely manipulating the morphology of nanoprobes.


Assuntos
Antioxidantes/análise , Colorimetria/métodos , Ouro/química , Nanopartículas Metálicas/química , Prata/química , Ressonância de Plasmônio de Superfície/métodos , Chá/química , Colorimetria/economia , Colorimetria/instrumentação , Nanopartículas Metálicas/ultraestrutura , Smartphone/instrumentação , Ressonância de Plasmônio de Superfície/economia , Ressonância de Plasmônio de Superfície/instrumentação
5.
Anal Bioanal Chem ; 408(19): 5359-67, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27225174

RESUMO

Identification of bioactive compounds directly from complex herbal extracts is a key issue in the study of Chinese herbs. The present study describes the establishment and application of a sensitive, efficient, and convenient method based on surface plasmon resonance (SPR) biosensors for screening active ingredients targeting tumor necrosis factor receptor type 1 (TNF-R1) from Chinese herbs. Concentration-adjusted herbal extracts were subjected to SPR binding assay, and a remarkable response signal was observed in Rheum officinale extract. Then, the TNF-R1-bound ingredients were recovered, enriched, and analyzed by UPLC-QTOF/MS. As a result, physcion-8-O-ß-D-monoglucoside (PMG) was identified as a bioactive compound, and the affinity constant of PMG to TNF-R1 was determined by SPR affinity analysis (K D = 376 nM). Pharmacological assays revealed that PMG inhibited TNF-α-induced cytotoxicity and apoptosis in L929 cells via TNF-R1. Although PMG was a trace component in the chemical constituents of the R. officinale extract, it had considerable anti-inflammatory activities. It was found for the first time that PMG was a ligand for TNF receptor from herbal medicines. The proposed SPR-based screening method may prove to be an effective solution to analyzing bioactive components of Chinese herbs and other complex drug systems. Graphical abstract Scheme of the method based on SPR biosensor for screening and recovering active ingredients from complex herbal extracts and UPLC-MS for identifying them. Scheme of the method based on SPR biosensor for screening and recovering active ingredients from complex herbal extracts and UPLC-MS for identifying them.


Assuntos
Técnicas Biossensoriais/instrumentação , Cromatografia Líquida de Alta Pressão/métodos , Medicamentos de Ervas Chinesas/química , Espectroscopia de Ressonância Magnética/instrumentação , Mapeamento de Interação de Proteínas/métodos , Receptores do Fator de Necrose Tumoral/química , Ressonância de Plasmônio de Superfície/instrumentação , Sítios de Ligação , Técnicas Biossensoriais/métodos , Descoberta de Drogas/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Ligantes , Espectroscopia de Ressonância Magnética/métodos , Extratos Vegetais/química , Plantas Medicinais/química , Ligação Proteica , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
6.
Food Chem ; 197(Pt A): 395-9, 2016 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-26616966

RESUMO

The stable silver nanorod (AgNR) sol in red was prepared by the two-step procedure of NaBH4-H2O2 and citrate heating reduction, and it exhibited a strong resonance Rayleigh scattering (RRS) peak at 346 nm. In pH 3.8 HAc-NaAc buffer solution, tea polyphenols (TP) reacted with ammonium molybdate (AM) to form yellow organic molybdate (OM) as receptor that was closed to the donor of AgNR, the RRS energy transfer (RRS-ET) takes place, owing to the overlapping between the AgNR RRS spectra and OM absorption spectra. When TP concentration increased, the RRS intensity decreased due to the RRS-ET increasing. So, a simple and sensitive AgNR surface plasmon RRS-ET analytical platform was fabricated to detect trace TP in the range of 0.05-0.85 µg/mL, with a detection limit of 0.03 µg/mL TP. The TP in tea samples was analyzed by this RRS-ET analysis platform, with satisfactory results.


Assuntos
Polifenóis/análise , Ressonância de Plasmônio de Superfície/métodos , Chá/química , Transferência de Energia , Nanotubos/química , Espalhamento de Radiação , Prata/química , Ressonância de Plasmônio de Superfície/instrumentação , Vibração
7.
J Biomed Opt ; 20(5): 051030, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25629389

RESUMO

This paper discusses one of the key problems of laser-induced tissue/cell hyperthermia mediated by gold nanoparticles, namely, quantifying and precise prediction of the light exposure to provide a controllable local heating impact on living organisms. The distributions of such parameters as an efficiency factor of absorption, differential and integral absorbing power of a nanoparticle, temperature increment, and Arrhenius damage integral were used to quantify nanoparticle effectiveness in the two-dimensional coordinate space "laser wavelength (λ) × radius of gold nanoparticles (R)." It was found that the fulfillment of required spatial and temporal characteristics of temperature fields in the vicinity of nanoparticle determines the optimal λ and R. As a result, the area in the space (λ × R) with a minimal criticality to alterations of the local hyperthermia may be significantly displaced from the position of the plasmonic resonance. The aspects of generalization of the proposed methodology for the analysis of local hyperthermia using nanoparticles of different shapes (nanoshells, nanorods, nanostars) and short pulse laser radiation are discussed.


Assuntos
Ouro/química , Hipertermia Induzida/métodos , Lasers , Nanopartículas Metálicas/química , DNA/química , Temperatura Alta , Humanos , Luz , Nanopartículas/química , Nanoconchas/química , Nanosferas/química , Nanotecnologia , Óptica e Fotônica , Tamanho da Partícula , Ressonância de Plasmônio de Superfície/instrumentação , Ressonância de Plasmônio de Superfície/métodos , Temperatura
8.
Appl Opt ; 53(28): 6527-36, 2014 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-25322242

RESUMO

We present designs of all-optical ultrafast YES/NOT, XOR/XNOR logic gates, binary counter, and double-bit comparator based on all-optical switching by two-photon absorption induced free-carrier injection in silicon 2 × 2 add-drop microring resonators. The proposed circuits have been theoretically analyzed using time-domain coupled-mode theory based on reported experimental values to realize low power (∼ 28 mW) ultrafast (∼ 22 ps) operation with high modulation (80%) and bit rate (45 Gb/s). The designs are complementary metal-oxide semiconductor compatible and provide advantages of high Q-factor, tunability, compactness, cascadibility, scalability, reconfigurability, simplicity, and minimal number of switches and inputs for realization of the desired logic. Although a two-bit counter has been shown, the scheme can easily be extended to N-bit counter through cascading.


Assuntos
Dispositivos Ópticos , Processamento de Sinais Assistido por Computador/instrumentação , Silício/química , Ressonância de Plasmônio de Superfície/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Miniaturização
9.
Sensors (Basel) ; 14(7): 11878-918, 2014 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-25004150

RESUMO

Electrochemical anodization of pure aluminum enables the growth of highly ordered nanoporous anodic alumina (NAA) structures. This has made NAA one of the most popular nanomaterials with applications including molecular separation, catalysis, photonics, optoelectronics, sensing, drug delivery, and template synthesis. Over the past decades, the ability to engineer the structure and surface chemistry of NAA and its optical properties has led to the establishment of distinctive photonic structures that can be explored for developing low-cost, portable, rapid-response and highly sensitive sensing devices in combination with surface plasmon resonance (SPR) and reflective interference spectroscopy (RIfS) techniques. This review article highlights the recent advances on fabrication, surface modification and structural engineering of NAA and its application and performance as a platform for SPR- and RIfS-based sensing and biosensing devices.


Assuntos
Óxido de Alumínio/química , Técnicas Biossensoriais/instrumentação , Interferometria/instrumentação , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Nanoporos/ultraestrutura , Ressonância de Plasmônio de Superfície/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Propriedades de Superfície , Transdutores
10.
Opt Express ; 22(8): 9508-16, 2014 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-24787839

RESUMO

We present the design of a three-dimensional (3D) polarization beam splitter (PBS) with a copper nanorod array placed between two silicon waveguides. The localized surface plasmon resonance (LSPR) of a metal nanorod array selectively cross-couples transverse electric (TE) mode to the coupler waveguide, while transverse magnetic (TM) mode passes through the original input waveguide without coupling. An ultra-compact and broadband PBS compared to all-dielectric devices is achieved with the LSPR. The output ports of waveguides are designed to support either TM or TE mode only to enhance the extinction ratios. Compared to silver, copper is fully compatible with complementary metal-oxide-semiconductor (CMOS) technology.


Assuntos
Cobre/química , Nanotubos , Refratometria/instrumentação , Semicondutores , Silício/química , Prata/química , Ressonância de Plasmônio de Superfície/instrumentação , Condutividade Elétrica , Desenho de Equipamento
11.
Opt Express ; 22 Suppl 6: A1596-603, 2014 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-25607317

RESUMO

A surface plasmon (SP)-enhanced nanoporous GaN-based green LED based on top-down processing technology has been successfully fabricated. This SP-enhanced LED consists of nanopores passing through the multiple quantum wells (MQWs) region, with Ag nanorod array filled in the nanopores for SP-MQWs coupling and thin Al(2)O(3) passivation layer for electrical protection. Compared with nanoporous LED without Ag nanorods, the electroluminescence (EL) peak intensity for the SP-enhanced LED was greatly enhanced by 380% and 220% at an injection current density of 1 and 20A/cm(2), respectively. Our results show that the increased EL intensity is mainly attributed to the improved internal quantum efficiency of LED due to the SP coupling between Ag nanorods and MQWs.


Assuntos
Óxido de Alumínio/química , Gálio/química , Iluminação/instrumentação , Nanopartículas Metálicas/química , Semicondutores , Ressonância de Plasmônio de Superfície/instrumentação , Adsorção , Transferência de Energia , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Nanopartículas Metálicas/ultraestrutura , Nanoporos/ultraestrutura , Espalhamento de Radiação
12.
Nanoscale ; 5(24): 12126-31, 2013 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-24162005

RESUMO

A unique quintuple-modality theranostic nanoprobe (QMT) is developed with gold nanostars for surface-enhanced Raman scattering (SERS), magnetic resonance imaging (MRI), computed tomography (CT), two-photon luminescence (TPL) imaging and photothermal therapy (PTT). The synthesized gold nanostars were tagged with a SERS reporter and linked with an MRI contrast agent Gd(3+). In vitro experiments demonstrated the developed QMT nanoprobe to be a potential theranostic agent for future biomedical applications.


Assuntos
Ouro , Nanopartículas Metálicas , Imagem Multimodal/métodos , Fototerapia/métodos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Ouro/uso terapêutico , Humanos , Luminescência , Medições Luminescentes/instrumentação , Medições Luminescentes/métodos , Imageamento por Ressonância Magnética/instrumentação , Imageamento por Ressonância Magnética/métodos , Nanopartículas Metálicas/uso terapêutico , Técnicas de Sonda Molecular/instrumentação , Imagem Multimodal/instrumentação , Neoplasias/patologia , Neoplasias/terapia , Fototerapia/instrumentação , Prognóstico , Análise Espectral Raman/instrumentação , Análise Espectral Raman/métodos , Ressonância de Plasmônio de Superfície/instrumentação , Ressonância de Plasmônio de Superfície/métodos , Tomografia Computadorizada por Raios X/instrumentação , Tomografia Computadorizada por Raios X/métodos
13.
ACS Nano ; 7(9): 8089-97, 2013 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-23961973

RESUMO

Plasmonic nanomaterials including gold nanorods are effective agents for inducing heating in tumors. Because near-infrared (NIR) light has traditionally been delivered using extracorporeal sources, most applications of plasmonic photothermal therapy have focused on isolated subcutaneous tumors. For more complex models of disease such as advanced ovarian cancer, one of the primary barriers to gold nanorod-based strategies is the adequate delivery of NIR light to tumors located at varying depths within the body. To address this limitation, a series of implanted NIR illumination sources are described for the specific heating of gold nanorod-containing tissues. Through computational modeling and ex vivo studies, a candidate device is identified and validated in a model of orthotopic ovarian cancer. As the therapeutic, imaging, and diagnostic applications of plasmonic nanomaterials progress, effective methods for NIR light delivery to challenging anatomical regions will complement ongoing efforts to advance plasmonic photothermal therapy toward clinical use.


Assuntos
Ouro/uso terapêutico , Hipertermia Induzida/instrumentação , Nanopartículas Metálicas/uso terapêutico , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/terapia , Fototerapia/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação , Animais , Linhagem Celular Tumoral , Desenho de Equipamento , Análise de Falha de Equipamento , Feminino , Humanos , Hipertermia Induzida/métodos , Raios Infravermelhos/uso terapêutico , Camundongos , Fototerapia/métodos , Próteses e Implantes , Ressonância de Plasmônio de Superfície/métodos , Resultado do Tratamento
14.
Opt Express ; 21(12): 14500-11, 2013 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-23787638

RESUMO

Breaking the reciprocity of light propagation in a nanoscale photonic integrated circuit (PIC) is a topic of intense research, fostered by the promises of this technology in areas ranging from experimental research in classical and quantum optics to high-rate telecommunications and data interconnects. In particular, silicon PICs fabricated in processes compatible with the existing complementary metal-oxide-semiconductor (CMOS) infrastructure have attracted remarkable attention. However, a practical solution for integrating optical isolators and circulators within the current CMOS technology remains elusive. Here, we introduce a new non-reciprocal photonic circuit operating with standard single-mode waveguides or optical fibers. Our design exploits a time-dependent index modulation obtained with conventional phase modulators such as the one widely available in silicon photonics platforms. Because it is based on fully balanced interferometers and does not involve resonant structures, our scheme is also intrinsically broadband. Using realistic parameters we calculate an extinction ratio superior to 20dB and insertion loss below 3dB.


Assuntos
Modelos Teóricos , Dispositivos Ópticos , Refratometria/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação , Telecomunicações/instrumentação , Simulação por Computador , Desenho Assistido por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Espalhamento de Radiação
15.
Opt Express ; 21(9): 11506-15, 2013 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-23670007

RESUMO

SiGe alloys present a large Infra-Red transparency window and a full compatibility with the standard Complementary Metal Oxide Semiconductor processing making them suitable for applications in integrated optics. In this paper we report on Mlines characterization of Si(1-x)Ge(x) graded index waveguides at 2.15 µm. First, a law giving the refractive index of a Si(1-x)Ge(x) alloy as a function of the Ge content x: n = 1.342x(2) + 0.295x + 3.451, has been experimentally established in the 0 < x < 0.4 range. Then, we have demonstrated that our methodology based on Mlines measurements can be used as short-loop non-destructive technique to provide feedback for sample growth.


Assuntos
Germânio/química , Refratometria/instrumentação , Silício/química , Ressonância de Plasmônio de Superfície/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento
16.
Opt Express ; 21(7): 8320-30, 2013 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-23571922

RESUMO

An extremely compact Si phase modulator is proposed and validated, which relies on effective modulation of the real part of modal index of horizontal metal-insulator-Si-insulator-metal plasmonic waveguides by a voltage applied between the metal cover and the Si core. Proof-of-concept devices are fabricated on silicon-on-insulator substrates using standard complementary metal-oxide-semiconductor technology using copper as the metal and thermal silicon dioxide as the insulator. A modulator with a 1-µm-long phase shifter inserted in an asymmetric Si Mach-Zehnder interferometer exhibits 9-dB extinction ratio under a 6-V/10-kHz voltage swing. Numerical simulations suggest that high speed and low driving voltage could be achieved by shortening the distance between the Si core and the n(+)-contact and by using a high-κ dielectric as the insulator, respectively.


Assuntos
Interferometria/instrumentação , Metais/química , Silício/química , Ressonância de Plasmônio de Superfície/instrumentação , Telecomunicações/instrumentação , Desenho Assistido por Computador , Condutividade Elétrica , Desenho de Equipamento , Análise de Falha de Equipamento , Miniaturização
17.
Anal Chem ; 85(9): 4560-6, 2013 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-23560643

RESUMO

Localized surface plasmon resonance (LSPR) spectroscopy has been widely used for label-free, highly sensitive measurements of interactions at a surface. LSPR imaging (LSPRi) has the full advantages of LSPR but enables high-throughput, multiplexed measurements by simultaneously probing multiple individually addressable sensors on a single sample surface. Each spatially distinct sensor can be tailored to provide data regarding different surface functionalities or reaction environments. Previously, LSPRi has focused on single-particle sensing where the size scale is very small. Here, we create defined macroscale arrays of nanoparticles that are compatible with common patterning methods such as dip-pen nanolithography and multichannel microfluidic delivery devices. With this new LSPR sensing format, we report the first demonstration of multiplexed LSPR imaging and show that the increased throughput of our instrument enables the collection of a complete Langmuir binding curve on a single sensor surface. In addition, the multiplexed LSPR sensor is highly selective, as demonstrated by the hybridization of single-stranded DNA to complementary sequences immobilized on the sensor surface. The LSPR arrays described in this work exhibit uniform sensitivity and tailorable optical properties, making them an ideal platform for high-throughput, label-free analysis of a variety of molecular binding interactions.


Assuntos
Técnicas Biossensoriais , Biotina/química , DNA/química , Nanopartículas/química , Ressonância de Plasmônio de Superfície , Técnicas Biossensoriais/instrumentação , Desenho de Equipamento , Estrutura Molecular , Ressonância de Plasmônio de Superfície/instrumentação , Propriedades de Superfície
18.
Opt Express ; 21(4): 4591-7, 2013 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-23481992

RESUMO

The paper describes the implementation of fiber Bragg gratings inscribed by femtosecond laser pulses with a wavelength of 400 nm. The use of a Talbot interferometer for the inscription process makes multiplexing practicable. We demonstrate the functionality of a three-grating multiplexing sensor and the temperature stability up to 1200 °C for a single first-order Bragg grating.


Assuntos
Óxido de Alumínio/química , Lasers , Ressonância de Plasmônio de Superfície/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Teste de Materiais , Propriedades de Superfície/efeitos da radiação
19.
Anal Chem ; 85(7): 3660-6, 2013 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-23432118

RESUMO

The development of new methods that meet the demand of high-throughput, high-fidelity screening of hit compounds is important to researching modalities of important diseases such as neurological disorders, HIV, and cancer. A surface plasmon resonance- (SPR-) based method capable of continuously screening enzyme inhibitors at a single chip with antibody-amplified signal enhancement has been developed. The proof of concept is demonstrated by monitoring the cleavage of chip-confined peptide substrates [a segment of the amyloid precursor protein (APP) with the Swiss mutation] by ß-site APP-cleaving enzyme 1 (BACE1). In the presence of a noninhibitor, BACE1 clips the peptide substrate at the cleavage site, detaching a fragment that is homologous to the N-terminus of the amyloid beta (Aß) peptide. Consequently, a subsequent injection of the Aß antibody does not lead to any molecular recognition or SPR signal change at the chip. In contrast, suppression of the BACE1 activity by a strong inhibitor leaves the peptide substrate intact, and the subsequent antibody attachment produces an easily detectable SPR signal. Compared to the widely used FRET (fluorescence resonance energy transfer) assay, the method reported here is more cost-effective, as unlabeled peptide is used as the BACE1 substrate. Furthermore, the assay is faster (each screening cycle lasts for ca. 1.5 h) and can be continuously carried out at a single, regenerable SPR chip for more than 30 h. Consequently, excellent reproducibility (RSD < 5%) and throughput can be attained. Two inhibitors were screened, and their half-maximal inhibitory concentrations (IC50) determined by the SPR method were in excellent agreement with values deduced from ELISA and mass spectrometry.


Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Secretases da Proteína Precursora do Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Ácido Aspártico Endopeptidases/metabolismo , Avaliação Pré-Clínica de Medicamentos/instrumentação , Inibidores Enzimáticos/farmacologia , Ressonância de Plasmônio de Superfície/instrumentação , Avaliação Pré-Clínica de Medicamentos/economia , Desenho de Equipamento , Humanos , Proteínas Recombinantes/metabolismo , Ressonância de Plasmônio de Superfície/economia
20.
Opt Express ; 21(2): 1840-8, 2013 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-23389168

RESUMO

The influence of three-photon absorption (3PA) on cross-phase modulation (XPM) effect in the mid-infrared (IR) region is theoretically investigated in silicon-on-sapphire (SOS) waveguides. It is found that the 3PA-induced nonlinear losses in the SOS waveguide will be considerable for the pulse propagation in the wavelength region of 2300 nm-3300 nm when the pump peak intensity is high enough. For the XPM process, the 3PA and 3PA-induced free-carrier effects can affect the spectrum and temporal profiles of the pump and signal pulses for sufficiently high pump peak intensities. Moreover, the XPM-induced frequency shift of signal spectrum is also discussed with different pump peak intensities, and the XPM-induced blue and red shifts are reduced due to 3PA.


Assuntos
Absorção , Óxido de Alumínio/química , Óxido de Alumínio/efeitos da radiação , Fótons , Silício/química , Ressonância de Plasmônio de Superfície/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Raios Infravermelhos
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