Conventional Surface Plasmon Resonance Biosensor Research Articles

Advances in Surface Plasmon Resonance-Based Biosensor Technologies for Cancer Cell Detection

Efforts have been made to enhance the surface sensitivity of the conventional surface plasmon resonance biosensor. To improve the sensitivity, a unique two-dimensional heterostructure layer of titanium disilicide and black phosphorus layer has been deposited over the metal surface. The titanium disilicide (TiSi2) nanosheet is placed in between silver (Ag) and black phosphorus (BP) films in the Kretschmann arrangement. This biosensor executes better over a wide range of refractive index variations, including biological cell distribution in individual blood. It may become a fast method of detecting cancerous cells and the several variants of corona and other viruses that become pandemic. Using the finite element method-based simulation technique, the sensitivity obtained as 195.4 degree/RIU, 167.6 degree/RIU, 212.4 degree/RIU, 168.4 degree/RIU, 212.4 degree/RIU, 186.6 degree/RIU, 218.6 degree/RIU, 195.4 degree/RIU, 203.6 degree/RIU, 202.6 degree/RIU 203.6 degree/RIU, and 202.6 for basal (skin cancer), basal (normal cell), HeLa (cervical cancer), MCF-7 (breast cancer), HeLa (normal cell), Jurkat (blood cancer), Jurkat (normal cell), PCI-2 (adrenal gland cancer), PCI-2 (normal cell), MDA-MB-231 (breast cancer), MDA-MB-231 (normal cell), MCF-7 (breast cancer), and MCF-7 (normal cell), respectively, and other performance parameters such as detection accuracy, figure of merit, and full width and half maximum (FWHM) are also evaluated.

Sensitivity Improvement of Surface Plasmon Resonance Biosensors with GeS-Metal Layers

Surface plasmon resonance (SPR) biosensors, with germanium sulfide (GeS) as a sensitive medium and Al/Ag/Au as the metal layers, are reported as we aim to improve the sensitivities of the biosensors. The sensitivities in conventional SPR biosensors, consisting of only metal Al, Ag, and Au layers, are 111°/RIU, 117°/RIU, 139°/RIU, respectively. Additionally, these sensitivities of the SPR biosensors based on the GeS-Al, GeS-Ag, and GeS-Au layers have an obvious improvement, resultant of 320°/RIU, 295°/RIU, and 260°/RIU, respectively. We also discuss the changing sensing medium GeS thickness using layer number to describe the scenario which brought about the diversification on the figure of merit (FOM) and optical absorption (OA) performance of the biosensors. These biosensors show obvious improvement of sensitivity and have strong SPR excitation to analytes; we believe that these kind biosensors could find potential applications in biological detection, chemical examination, and medical diagnosis.

Plasmonic biosensor based on a gold nanostripe array for detection of microRNA related to myelodysplastic syndromes

We present a new optical biosensor based on surface plasmons excited on an array of gold nanostripes via attenuated total reflection. We investigate performance of the biosensor using a theoretical model that considers both optical and mass transport aspects. The analysis of optical aspects employs two different approaches: a complex model incorporating optical characteristics of the nanostructure as well as the noise characteristics of the optical readout system and a simple model based solely on the figure of merit of the nanostructure. The theoretical analysis suggests that the optimized biosensor is able to detect molecular analytes at concentrations lower by a factor of ~ 10 than conventional surface plasmon resonance biosensors. In order to validate the theoretical model, we characterize the gold nanostripe arrays of different designs in model refractometric and biosensing experiments. We show that the nanoplasmonic sensor exhibits refractive index sensitivity of 1989 nm/RIU and refractive index resolution down to 3.6×10−7RIU. In addition, we use the nanoplasmonic biosensor for the detection of a microRNA biomarker of myelodysplastic syndromes (miRNA-125b) and demonstrate that the biosensor can detect miRNA-125b at concentrations down to ~ 17 pM.

Improved Performance of Platinum Diselenide Based Surface Plasmon Resonance Biosensor Using Silicon

After the discovery of graphene in 2004, two-dimensional materials have attracted attention at large scale because of their peculiar structure and extraordinary properties. As they have large potential in future nano electronics, two-dimensional transition metal dichalcogenides has become most focus topic of study. Transition metal dichalcogenides with tunable finite band gap and significant transitional behavior are much suitable for the construction of electronic and optoelectronic devices of high-performance. However, platinum diselenide is group-10 transition metal dichalcogenides which occur naturally in one phase transition, which has been theoretically predicted as an excellent material. The proposed structure of surface plasmon resonance (SPR) -based biosensor consists of a silicon and two-dimensional nanomaterial platinum diselenide. The performance parameters of proposed biosensor (surface plasmon resonance-based) such as detection accuracy, figure of merit, sensitivity, full width at half maximum have been investigated. The sensitivity, detection accuracy, full width half maximum and figure of merit of proposed surface plasmon resonance biosensor having silver (50 nm), silicon (2 nm) and one layer of platinum diselenide with 2 nm thickness at 633 nm wavelength is 2200RIU–1 , 0.20 deg–1, 4.980 and 44.22 RIU–1 respectively. Silicon sheet is used in the middle of the Ag and platinum diselenide to prevent the oxidation of silver and enhance the sensitivity of platinum diselenide based surface plasmon resonance biosensor. The sensitivity of conventional surface plasmon resonance biosensor and the proposed surface plasmon resonance biosensor without silicon layer is 1700RIU–1 and 2000RIU–1 respectively. Surface plasmon resonance biosensor of device structure CaF2/Ag/Si/PtSe2 has higher sensitivity in comparison to device structures CaF2/Ag (conventional) and CaF2/Ag/PtSe2 (without Silicon Layer) by 29.41% and 10% respectively. Although the highest sensitivity obtained is 2620RIU–1 for 60 nm silver with 3 nm silicon layer except the platinum diselenide layer.

FDTD Analysis Fiber Optic SPR Biosensor for DNA Hybridization: A Numerical Demonstration with Graphene

This article illustrates a design and finite difference time domain (FDTD) method based on analysis of fiber optic surface plasmon resonance (SPR) biosensor for biomedical application especially for DNA-DNA hybridization. The fiber cladding at the middle portion is constructed with the proposed hybrid of gold (Au), graphene, and a sensing medium. This sensor can be recognized adsorption of DNA biomolecules onto sensing medium of PBS saline using attenuated total reflection (ATR) technique. The refractive index (RI) is varied owing to the adsorption of different concentration of biomolecules. Result states that the sensitivity with a monolayer of graphene will be improved up to 40% than bare graphene layer. Owing to increased adsorption capability of DNA molecules on graphene, sensitivity increases compared to the conventional gold thin film SPR biosensor. Numerical analysis shows that the variation of the SPR angle for mismatched DNA strands is quite negligible, whereas that for complementary DNA strands is considerable, which is essential for proper detection of DNA hybridization. Finally, the effect of Electric field distribution on inserting graphene layer is analyzed incorporating the FDTD technique by using Lumerical FDTD solution software.

Sensitivity enhancement of surface plasmon resonance sensors with 2D franckeite nanosheets

Abstract As a latest novel two-dimensional (2D) material with naturally occurring van der Waals heterostructure, franckeite has the unique advantages compared with the artificial stacking heterostructures. Herein, we propose a surface plasmon resonance (SPR) sensor with 2D franckeite nanosheets to improve the sensitivity. In this structure, franckeite is covered on the surface of 50 nm silver film, so that the SPR sensitivity is related to the thickness of the franckeite overlayer. The sensitivity as high as 188 °/RIU in theory has been obtained, which is a 62% increasing compared with the conventional SPR biosensor. Moreover, an additional film of graphene is considered for the virtue of bio-compatible, and the sensitivity of the franckeite-graphene heterostructures is furthermore improved. As an air-stable 2D material, we believe that 2D franckeite nanosheets could have potential applications in the field of chemical and biological sensors in the future.

Sensitivity enhancement of a graphene–barium titanate-based surface plasmon resonance biosensor with an Ag–Au bimetallic structure in the visible region

In this study, a surface plasmon resonance (SPR) biosensor based on graphene–barium titanate nanocomposites is optimized by using an Ag–Au bimetallic configuration to achieve sensitivity enhancement. The angular interrogation method is used for the analysis of the reflectance from the sensor. By optimizing parameters, a sensitivity and figure of merit as high as 294°/RIU and 42.13 1/RIU can be obtained with Ag–Au bimetallic film at a wavelength of 633 nm. Compared with conventional SPR biosensors with a single metal film, the sensitivity of the proposed biosensor with Ag–Au bimetallic film can be greatly enhanced. Also, Au thin film can be used as a protective layer to prevent oxidation of the Ag layer.

Zinc oxide, gold and graphene-based surface plasmon resonance (SPR) biosensor for detection of pseudomonas like bacteria: A comparative study

In the present paper, we have studied the better performance of zinc oxide (ZnO), gold (Au) and graphene-based SPR biosensor for the detection of pseudomonas and pseudomonas like bacteria. The performance of proposed SPR biosensor is based on theoretical analysis of the sensitivity, detection accuracy, quality parameter and electric field intensity enhancement factor (EFIEF) with angular interrogation method. In this biosensor, prism (BK-7 glass) base is coated with ZnO followed by Au, graphene and different affinity layers, water is used as sensing medium. The advantage of the present biosensor is the hybrid structure of graphene, gold and ZnO with enhanced sensitivity in which the molecular recognition sites on graphene bind strongly the pseudomonas like bacteria with the help of affinity layers. ZnO is responsible for the larger shift in resonance angle that leads a significant enhancement in the sensitivity of the present biosensor. On analyzing the results, we have found that the proposed biosensor has a greater sensitivity of 187.43 deg/RIU, detection accuracy of 2.05 deg-1 and quality parameter of 29.33 RIU-1 as compared to the other reported conventional SPR biosensor for the detection of pseudomonas like bacteria.

Sensitive Detection of Exosomal Proteins via a Compact Surface Plasmon Resonance Biosensor for Cancer Diagnosis.

Exosomes are small extracellular vesicles released by cells for cell-cell communication. They play important roles in cancer development, metastasis, and drug resistance. Exosomal proteins have been demonstrated by many studies as promising biomarkers for cancer screening, diagnosis, and monitoring. Among many detection techniques, surface plasmon resonance (SPR) is a highly sensitive, label-free, and real-time optical detection method. Commercial prism-based wavelength/angular-modulated SPR sensors afford high sensitivity and resolution, but their large footprint and high cost limit their adaptability for clinical settings. Recently, a nanoplasmonic exosome (nPLEX) assay was developed to detect exosomal proteins for ovarian cancer diagnosis. However, comparing with conventional SPR biosensors, the broad applications of nanoplasmonic biosensors are limited by the difficult and expensive fabrication of nanostructures. We have developed an intensity-modulated, compact SPR biosensor (25 cm × 10 cm × 25 cm) which uses a conventional SPR sensing mechanism and does not require nanostructure fabrication. Calibration from glycerol showed that the compact SPR biosensor offered sensitivity of 9.258 × 103%/RIU and resolution of 8.311 × 10-6 RIU. We have demonstrated the feasibility of the compact SPR biosensor in lung cancer diagnosis using exosomal epidermal growth factor receptor (EGFR) and programmed death-ligand 1 (PD-L1) as biomarkers. It detected a higher level of exosomal EGFR from A549 nonsmall cell lung cancer (NSCLC) cells than BEAS-2B normal cells. With human serum samples, the compact SPR biosensor detected similar levels of exosomal EGFR in NSCLC patients and normal controls, and higher expression of exosomal PD-L1 in NSCLC patients than normal controls. The compact SPR biosensor showed higher detection sensitivity than ELISA and similar sensing accuracy as ELISA. It is a simple and user-friendly sensing platform, which may serve as an in vitro diagnostic test for cancer.

Tuning and Sensitivity Enhancement of Surface Plasmon Resonance Biosensor With Graphene Covered Au-MoS 2-Au Films

In the conventional surface plasmon resonance biosensor, the sensitivity using angular interrogation is low. Graphene/MoS2 has been attached on the metal surface to improve the sensitivity; however, the ability to improve sensitivity is limited. Here, by sandwiching the MoS2 sheets between two gold films in the Kretschmann configuration, we demonstrate an ultrasensitive surface plasmon resonance sensor. By optimizing the structure of sensor, we find that the sensitivity as high as 182°/RIU can be realized with 4-layers MoS2 and a monolayer graphene. Moreover, it is indicated that the sensitivity can be tuned and controlled by changing the layer numbers of graphene and MoS2.

Comparative study of a Surface Plasmon Resonance Biosensor based on Metamaterial and Graphene

In this study, a surface plasmon resonance biosensor at near infrared frequency based on a metamaterial is proposed. The proposed biosensor utilizes the properties of plasmons and metamaterial for enhancement of its performance parameters i.e. sensitivity, detection accuracy and quality factor. The thickness of the metamaterial and gold film has been optimized for optimal performance of the proposed biosensor at near infrared wavelengths. Results obtained from the proposed biosensor were compared with existing two-dimensional nanomaterials such as a graphene based biosensor and a conventional surface plasmon resonance biosensor. Finally, it is observed that the performance parameters of the proposed biosensor are very high when compared to existing surface plasmon resonance biosensors.

Effect of Molybdenum Disulfide Layer on Surface Plasmon Resonance Biosensor for the Detection of Bacteria

In this study, a molybdenum disulfide (MoS2) based surface plasmon resonance (SPR) biosensor is proposed. The reflectance curves for the proposed SPR biosensor are analyzed and compared with the graphene based and the conventional SPR biosensors. It is observed that the performance parameters of the proposed biosensor- sensitivity, detection accuracy, and the quality factor are enhanced by the utilization of the adsorption property of MoS2 for monolayer and bi-layer MoS2. Also, the effect of increasing the number of layers of MoS2 on the reflectance curve is analyzed and compared.

An Improved Sensitivity SPR Biosensor Using Multilayer Graphene

A graphene-based Surface Plasmon Resonance (SPR) biosensor is presented. Graphene layers added to a conventional gold thin film SPR biosensor leads to a drastic increase in sensitivity due to the increased biomolecule adsorption in the graphene layers. In comparison to conventional SPR sensors this produces a large change in the refractive index at the metal-dielectric interface. The reflection of light coupled into a SPR mode propagating along a thin Au-graphene layer surrounded by dielectric is calculated and compared to a conventional SPR sensor.

Sensitivity improvement of graphene based surface plasmon resonance biosensors with chaclogenide prism

Graphene and chalcogenide prism based surface plasmon resonance (SPR) biosensor used for the detection of Pseudomonas and Pseudomonas-like bacteria is presented in this paper. Angular responses, sensitivity, detection accuracy and quality parameter of SPR biosensor is investigated. This biosensor comprises of chalcogenide prism which is coated with gold layer and graphene layers. The proposed biosensor uses Kretschmann configuration to detect the change in refractive index near the sensor surface. By comparing these results with the conventional surface plasmon resonance biosensor coated with gold layer and chalcogenide prism, it is observed that the proposed SPR biosensor has sensitivity 6.47 times greater than that of chalcogenide prism based conventional SPR sensor. Also, the dependence of sensitivity, detection accuracy and quality parameter on the number of graphene layers for the proposed sensor is plotted and analyzed.

Dual-Wavelength Spectroscopy of a Metallic-Grating-Coupled Surface Plasmon Resonance Biosensor

A novel approach is proposed to decouple the surface and bulk effects in surface plasmon resonance (SPR) biosensors. This method is based on a metallic-grating-based SPR in which a sensor is efficiently optimized to excite three surface plasmon waves at two different wavelengths. Decoupling surface and bulk effects can be realized using this technique by tracing the resonance angle variations corresponding to each excited mode. To optimize the sensor, a genetic algorithm is applied, and finally, the performance of the sensor is compared with the conventional single-interface SPR biosensor.

Field enhancement and target localization impact on the biosensitivity of nanostructured plasmonic sensors

Surface plasmon resonance (SPR) biosensors using field enhancement in nanograting surfaces can overcome sensitivity limitations of conventional SPR biosensors. Nevertheless, the correlation of the local field enhancement established in such structures with sensitivity enhancement has not been extensively studied. We present a numerical study of the coupling effect between the various plasmon modes present in nanograting structures with various structural parameters. We give here a quantitative demonstration of the improvement in sensing performance of SPR biosensors by selective localization of the target molecules in the regions where the electromagnetic field intensity is locally enhanced.

Enhanced SPR Sensitivity with Nano-Micro-Ribbon Grating—an Exhaustive Simulation Mapping

In this study, we theoretically investigate the sensing potential of 2D nano- and micro-ribbon grating structuration on the surface of Kretschmann-based surface plasmon resonance (SPR) biosensors when they are employed for detection of biomolecular binding events. Numerical simulations were carried out by employing a model based on the hybridization of two classical methods, the Fourier modal method and the finite element method. Our calculations confirm the importance of light manipulation by means of structuration of the plasmonic thin film surfaces on the nano- and micro-scales. Not only does it highlight the geometric parameters that allow the sensitivity enhancement compared with the response of the conventional SPR biosensor based on a flat surface but also describes the transition from the regime where the propagating surface plasmon mode dominates to the regime where the localized surface plasmon mode dominates. An exhaustive mapping of the biosensing potential of the 2D nano- and micro-structured biosensors surface is presented, varying the structural parameters related to the ribbon grating dimensions, i.e., the widths and thicknesses. The nano- and micro-structuration also leads to the creation of regions on biosensor chips that are characterized by strongly enhanced electromagnetic (EM) fields. New opportunities for further improving the sensitivity are offered if localization of biomolecules can be carried out in these regions of high EM fields. The continuum of nano- and micro-ribbon structured biosensors described in this study should prove a valuable tool for developing sensitive and reliable 2D-structured plasmonic biosensors.

Simulation and Analysis of a Sub-Wavelength Grating Based Multilayer Surface Plasmon Resonance Biosensor

This paper presents a subwavelength grating based multilayer surface plasmon resonance biosensor (SPRB) which includes a periodic array of subwavelength grating on top of a layer of graphene sheet in the biosensor. The proposed biosensor is named grating-graphene SPRB (GG-SPRB). The aim of the proposed multilayer structure is to improve the sensitivity of the SPRB through monitoring of the biomolecular interactions of DNA hybridization. Significant sensitivity improvement is obtained for the GG-SPRB compared with the conventional SPRB. The result of the numerical investigation of the GG-SPRB is presented and compared with a theoretically developed multilayer matrix formalism, and a good agreement has been observed. In addition, an optimization of the grating dimensions including volume factor, grating depth, grating angle, grating period, and grating geometry (e.g., rectangular, sinusoidal and triangular) is presented. The outcome of the investigation presented in this paper identifies desired functioning conditions corresponding to the best design parameters for the GG-SPRB.

Dual Polarization Measurements in the Hybrid Plasmonic Biosensors

A novel affinity biosensor is proposed based on the hybrid plasmonic platform. The proposed biosensor benefits from the high sensitivity of the surface plasmon resonance (SPR), while at the same time, it is capable of performing measurements in both the TM and TE polarizations (p- and s-polarizations). Unlike the conventional SPR biosensors, the polarization diversity of the hybrid sensor allows for decoupling of the bulk index variations in the fluidic channels (due to variations in concentration, decomposition, temperature, and so on) from the surface properties of the attached molecules. Compatibility of the proposed hybrid plasmonic biosensor with standard Si-processing techniques and the simplicity of its design are other advantages of the sensor which makes its fabrication straightforward. The best figure of merit for the biosensor is defined based on the minimum detection limit and a genetic algorithm is used to optimize the device. A method of de-convolving the surface and bulk effects is also discussed.

Ag/Au bi-metallic film based color surface plasmon resonance biosensor with enhanced sensitivity, color contrast and great linearity

In wavelength surface plasmon resonance (SPR) biosensor, the manipulation of SPR dispersion relation by Ag/Au bi-metallic film was first time implemented. Due to the enhanced resonant wavelength shift and the sharper SPR slope of using Ag/Au bi-metallic film, the illuminated color of reflection shows one order of magnitude greater contrast than conventional SPR biosensors. Such an Ag/Au bi-metallic film based color SPR biosensor (CSPRB) allows the detail bio-interactions, for example 100nM streptavidin, to be distinguished by directly observing the color change of reflection through naked eyes rather than the analysis of spectrometer. In addition to the enhanced sensitivity and color contrast, this CSPRB also possesses a great linear detection range up to 0.0254RIU, which leading to the application of point-of-care tests.