Optical Surface Plasmon Resonance Biosensor Research Articles

Modeling of a highly sensitive MoS2-Graphene hybrid based fiber optic SPR biosensor for sensing DNA hybridization

Optical fiber instead of prism is now widely studied in biosensing research. This paper investigates a highly sensitive optical fiber based Ag-MoS2-Graphene hybrid surface plasmon resonance (SPR) biosensor for sensing DNA hybridization. Sensitivity, detection accuracy and quality factor are carefully studied for the performance analysis. Numerical study shows that usingsingle layer of MoS2 in the middle of a Graphene-on-Ag layer, the fiber optic biosensor exhibits high sensitivity of 105.71°/RIU with reasonable detection accuracy and quality factor of 1.626 and 23.23 RIU−1, respectively. This enhanced sensitivity is due to the absorption ability and optical characteristics of graphene biomolecules and high fluorescence quenching ability of MoS2. Numerical investigation also reflects the variation of resonance angle and spectrum of transmitted power for mismatched DNA strands and for complementary DNA strands. These variations are negligible for mismatched DNA strands whereas significantly computable for complementary DNA strands. Thus the proposed sensor effectively differentiates hybridization and single nucleotide polymorphisms (SNP) by examining the level of changes in resonance angle and transmitted power spectrum. Therefore, this fiber optic based Ag-MoS2-Graphene hybrid biosensor might be a promising candidate for the detection of DNA hybridization.

Graphene coated fiber optic surface plasmon resonance biosensor for the DNA hybridization detection: Simulation analysis

In this paper, a graphene coated optical fiber surface plasmon resonance (SPR) biosensor is presented for the detection of DNA Hybridization. For the proposed sensor, a four layer model (fiber core /metal /sensing layer /sample) where a sheet of graphene (biomolecular recognition elements ( BRE)) acting as a sensing layer is coated around the gold film because graphene enhances the sensitivity of fiber optic SPR biosensor. Numerical analysis shows the variation of resonance wavelength and spectrum of transmitted power for mismatched DNA strands and for complementary DNA strands. For mismatched DNA strands variation is negligible whereas for complementary DNA strands is considerably countable. Proposed sensor successfully distinguishes hybridization and single nucleotide polymorphisms (SNP) by observing the variation level of resonance wavelength and spectrum of transmitted power.

A Universal Surface for Label-Free Electrical and Optical Sensing of Disease Markers

Quantitative point-of-care (POC) diagnostic tools are crucial for next-generation human (and animal) health monitoring and disease diagnosis to rapidly infer effective treatment decisions. ELISA based disease diagnostics is often performed off-site in centralized labs, requiring long turnaround times (>72hrs), reducing the effective period for disease intervention. In this study, a gold sensing surface is shown to provide ELISA-equivalent results across multiple label-free and rapid biosensing platforms including potentiometric field-effect transistor (FET) biosensors, electrochemical impedance spectroscopy (EIS) biosensors and surface plasmon resonance (SPR) devices. Using the model pathogen Bovine Herpes Virus 1 (BHV-1) (a major source of economic loss in the agri-food industry globally 1), BHV-1 glycoprotein E (gE) was attached to sensor surfaces to detect the immunological interaction against anti-BHV-1 antibodies. The use of a gold sensing surface offers access to the well-established thiol surface functionalization and protein immobilization via amine coupling. This functionalized gold sensing surface is used to compare the response of ELISA in four different sensing platforms: (1) as the gate electrode for graphene ion-sensitive field-effect transistor (ISFET), (2) as the gate electrode for extended-gate field-effect transistor (EGFET) sensors (3) as the working electrode (WE) for EIS sensors, and (4) as the sensing surface for SPR. The results show that the sensitivity of the EGFET biosensors is equivalent to the ISFETs.2 Moreover, EGFET biosensors provide many advantages including improved reliability by separating the sensor and transducer components, low-cost and easy fabrication, disposable chip design and high compatibility with state-of-art semiconductor technologies.3-5 While the mechanism for EIS is quite different than potentiometric FET-based sensing, the dynamic response is found to be equivalent. Similarly, the same Au surface can be used in optical SPR biosensors using the same surface chemistry. The universality of a Au sensing surface allows detection using multi-platforms but with a single chip and, therefore, simplifies the sample preparation and reduces the required sample volumes for diagnostics. All three electrical sensors demonstrate performance equivalent to SPR and ELISA, with dynamic range approaching the limit of detection for sera dilutions < 10-3of anti-BHV-1 antiserum. However, the potentiometric and EIS sensors provide results much faster (~10 min.) than SPR (~2 hr.) and ELISA (> 20 hr.) Additionally, the electronic biosensors are compact in size and are promising for POC devices. In conclusion, a gold surface is shown to provide universal and equivalent sensing across multiple platforms using well-established surface chemistry. Furthermore, the use of one surface to facilitate integration of multiple sensing mechanisms can potentially improve specificity. Among all of the available biosensor technologies, electrical biosensors provide rapid, label-free and cost-efficient sensing capability in a compact size, which is promising for quantitative point-of-care devices. 1G. D. Snowder et al. Journal of Animal Science 85, 1885 (2007). 2A. Tarasov et al. 2D Materials 2, 044008 (2015). 3L.-L. Chi et al. Materials Chemistry and Physics 63 , 19 (2000). 4P. Dak et al. Device Research Conference (DRC), 2013 71st Annual, 105 (2013). 5W. Guan et al. Biosensors and Bioelectronics 51, 225 (2014).

Optical surface plasmon resonance biosensors in molecular fishing

Optical surface plasmon resonance biosensors in molecular fishing

Optical surface plasmon resonance biosensors in molecular fishing

An optical biosensor employing surface plasmon resonance is a highly efficient instrument applicable for direct real time registration of molecular interactions without additional use of any labels or coupled processes. As an independent approach it is especially effective in analysis of various ligand receptor interactions. SPR-biosensors are used for validation of studies on intermolecular interactions in complex biological systems (affinity profiling of various groups of proteins, etc.). Recently, potential application of the SPR-biosensor for molecular fishing (direct affinity binding of target molecules from complex biological mixtures on the optical biosensor surface followed by their elution for identification by LC-MS/MS) has been demonstrated. Using SPR-biosensors in such studies it is possible to solve the following tasks: (a) SPR-based selection of immobilization conditions required for the most effective affinity separation of a particular biological sample; (b) SPR-based molecular fishing for subsequent protein identification by mass spectrometry; (c) SPR-based validation of the interaction of identified proteins with immobilized ligand. This review considers practical application of the SPR technology in the context of recent studies performed in the Institute of Biomedical Chemistry on molecular fishing of real biological objects.

Testing a Microarray to Detect and Monitor Toxic Microalgae in Arcachon Bay in France.

Harmful algal blooms (HABs) occur worldwide, causing health problems and economic damages to fisheries and tourism. Monitoring agencies are therefore essential, yet monitoring is based only on time-consuming light microscopy, a level at which a correct identification can be limited by insufficient morphological characters. The project MIDTAL (Microarray Detection of Toxic Algae)—an FP7-funded EU project—used rRNA genes (SSU and LSU) as a target on microarrays to identify toxic species. Furthermore, toxins were detected with a newly developed multiplex optical Surface Plasmon Resonance biosensor (Multi SPR) and compared with an enzyme-linked immunosorbent assay (ELISA). In this study, we demonstrate the latest generation of MIDTAL microarrays (version 3) and show the correlation between cell counts, detected toxin and microarray signals from field samples taken in Arcachon Bay in France in 2011. The MIDTAL microarray always detected more potentially toxic species than those detected by microscopic counts. The toxin detection was even more sensitive than both methods. Because of the universal nature of both toxin and species microarrays, they can be used to detect invasive species. Nevertheless, the MIDTAL microarray is not completely universal: first, because not all toxic species are on the chip, and second, because invasive species, such as Ostreopsis, already influence European coasts.

Surface plasmon resonance based biosensor technique: A review

Optical Surface plasmon resonance (SPR) biosensors represent the most advanced and developed optical label-free biosensor technology. Optical SPR biosensors are a powerful detection and analysis tool that has vast applications in environmental protection, biotechnology, medical diagnostics, drug screening, food safety and security. This article reviews the recent development of SPR biosensor techniques, including bulk SPR and localized SPR (LSPR) biosensors, for detecting interactions between an analyte of interest in solution and a biomolecular recognition. The concepts of bulk and localized SPs and the working principles of both sensing techniques are introduced. Major sensing advances on biorecognition elements, measurement formats, and sensing platforms are presented. Finally, the discussions on both biosensor techniques as well as comparison of both SPR sensing techniques are made.

Validation of an optical surface plasmon resonance biosensor assay for screening (fluoro)quinolones in egg, fish and poultry

A surface plasmon resonance biosensor immunoassay has been developed for multi-residue determination of 13 (fluoro)quinolone antibiotics in poultry meat, eggs and fish. The following performance characteristics were determined according to the guidelines laid down for screening assay validation in European Decision 2002/657/EC: detection capability, specificity/selectivity, decision limit, repeatability, ruggedness and stability. The detection capability estimated for norfloxacin, the reference fluoroquinolone, was below 0.5, 1 and 1.5 ng g−1 for poultry meat, egg and fish, respectively. The screening assay proved specific and showed satisfactory sensitivity below the MRL levels even though flumequine and oxolinic acid had lower cross-reactivities. A wide range of non-MRL substances were also detected at concentrations below 10 ng g−1. Repeatability was good with both intra- and inter-assay coefficients of variation <6%; ruggedness was also demonstrated.

Fiber optic SPR biosensing of DNA hybridization and DNA–protein interactions

In this paper we present a fiber optic surface plasmon resonance (SPR) sensor as a reusable, cost-effective and label free biosensor for measuring DNA hybridization and DNA–protein interactions. This is the first paper that combines the concept of a fiber-based SPR system with DNA aptamer bioreceptors. The fibers were sputtered with a 50nm gold layer which was then covered with a protein repulsive self-assembled monolayer of mixed polyethylene glycol (PEG). Streptavidin was attached to the PEG's carboxyl groups to serve as a versatile binding element for biotinylated ssDNA. The ssDNA coated SPR fibers were first evaluated as a nucleic acid biosensor through a DNA–DNA hybridization assay for a random 37-mer ssDNA. This single stranded DNA showed a 15 nucleotides overlap with the receptor ssDNA on the SPR fiber. A linear calibration curve was observed in 0.5–5μM range. A negative control test did not reveal any significant non-specific binding, and the biosensor was easily regenerated. In a second assay the fiber optic SPR biosensor was functionalized with ssDNA aptamers against human immunoglobulin E. Limits of detection (2nM) and quantification (6nM) in the low nanomolar range were observed. The presented biosensor was not only useful for DNA and protein quantification purposes, but also to reveal the binding kinetics occurring at the sensor surface. The dissociation constant between aptamer and hIgE was equal to 30.9±2.9nM. The observed kinetics fully comply with most data from the literature and were also confirmed by own control measurements.

Optical fiber SPR biosensor with sandwich assay for the detection of prostate specific antigen

We present a new, sensitive, few mode fiber (FMF) surface plasmon resonance (SPR) biosensor with a sandwich assay for the detection of PSA. The side-polished FMF biosensor does not need a polarizer and a thin high-index overlayer. The optical sensitivity of the SPR sensor was determined as 2.5 × 10 −6 RIU. In the SPR PSA sensor, the SPR signals were amplified by a factor of 6 in average over no secondary antibody, using the sandwich assay. The proposed FMF SPR biosensor has great potential for real-time analysis of immune reaction between biomolecules and the advantages of high-sensitivity and label-free detection.

Development of an optical surface plasmon resonance biosensor assay for (fluoro)quinolones in egg, fish, and poultry meat

The aim of this study was to develop an optical biosensor inhibition immunoassay, based on the surface plasmon resonance (SPR) principle, for use as a screening test for 13 (fluoro)quinolones, including flumequine, used as veterinary drugs in food-producing animals. For this, we immobilised various quinolone derivatives on the sensor chip and tested binding of a range of different antibodies (polyclonal and one engineered antibody) in the presence and absence of free (fluoro)quinolones. The main challenge was to detect flumequine in an assay giving good results for the other compounds. One antigen–antibody combination proved satisfactory: polyclonal antibodies raised against a dual immunogen and, on the sensor chip, a fluoroquinolone derivative. It was the first time that this concept of the bi-active antibody was described in the literature. The assay, optimised for detection in three matrices (poultry muscle, fish, and egg), was tested on incurred samples prepared by liquid extraction followed by two washing steps. This rapid, simple method proved adequate for detecting at least 13 (fluoro)quinolones at concentrations below established maximum residue levels (MRLs). The reference molecule norfloxacin could be detected in the range of 0.1–10 μg kg −1 in extracts of egg and poultry meat and in the range of 0.1–100 μg kg −1 in extracts of fish. The determined midpoints of these calibration curves were about 1, 1.5 and 3 μg kg −1 in poultry meat, egg and fish, respectively.

RAPID DETECTION OF SALMONELLA ENTERITIDIS AND ESCHERICHIA COLI USING SURFACE PLASMON RESONANCE BIOSENSOR

ABSTRACT The Biacore surface plasmon resonance (SPR)‐based biosensor was used to detect Salmonella enterica serovar Enteritidis and Escherichia coli in spiked skim milk using specific antibodies. The optical SPR biosensor registers changes in the refractive index during binding of the analyte (bacteria) to the ligand (antibody) on the gold‐coated sensor chip surface. Immobilized protein A‐captured specific antibodies were used to detect the bacteria in less than an hour. The reaction was found to be specific, and the limits of detection of the assay were found to be 25 cfu/mL for E. coli and 23 cfu/mL for Salmonella. Because the assays were shown to be sensitive, reproducible and very specific, the SPR‐based Biacore biosensor has the potential for near real‐time, yet specific, detection and presumptive identification of bacteria in food and water.

Real-time optical biosensor based on differential phase measurement of surface plasmon resonance

We report a real-time differential phase measurement technique which can be implemented in optical surface plasmon resonance biosensors. The important feature of our design is that sensitivity has been greatly improved by measuring the differential phase change between the s and p-polarizations. Real-time measurement capability is achieved by using a phase extracting routine which continuously monitors the waveforms captured by two photo-detectors. Measurement capability of our setup is demonstrated through real-time monitoring of bovine serum albumin (BSA)/anti-BSA binding reaction. The estimated sensitivity of our current setup is 7.4 ng/ml.

Immunochemical detection of Salmonella group B, D and E using an optical surface plasmon resonance biosensor

A surface plasmon resonance biosensor (Biacore) was used to detect Salmonella through antibodies reacting with Salmonella group A, B, D and E (Kauffmann–White typing). In the assay designed, anti- Salmonella antibodies immobilized to the biosensor surface were allowed to bind injected bacteria followed by a pulse with soluble anti- Salmonella immunoglobulins to intensify the signal. No significant interference was found for (mixtures of) 30 non- Salmonella serovars at 10 9 CFU ml −1. A total of 53 Salmonella serovars were successfully detected at 1×10 7 CFU ml −1, except those of groups C, G, L and P, as expected. The cut-off point was determined with an equicellular mixture of Salmonella enteritidis and Salmonella typhimurium at a final amount of 1.7×10 3 CFU per test portion. Although further work is needed to cover the detection of all relevant Salmonella serovars in food-producing animals and food products, this work demonstrates the merits of this alternative biosensor approach in terms of automation, sensitivity, specificity, simple handling and limited hands-on time.