Principle Of Surface Plasmon Resonance Research Articles

Multiplexed Opto-Microfluidic Biosensing: Advanced Platform for Prostate Cancer Detection.

Cancer stands as a prominent global cause of mortality, necessitating early detection to augment survival rates and alleviate economic burdens on healthcare systems. In particular, prostate cancer (PCa), impacting 1.41 million men globally in 2020, accentuates the demand for sensitive and cost-effective detection methods beyond traditional prostate-specific antigen (PSA) testing. While clinical techniques exhibit limitations, biosensors emerge as compact, user-friendly alternatives to traditional laboratory approaches. However, existing biosensors predominantly concentrate on PSA detection, prompting the necessity for advancing toward multiplex sensing platforms. This study introduces a compact opto-microfluidic sensor featuring a substrate of gold nanospikes, fabricated via electrodeposition, for enhanced sensitivity. Embedded within a microfluidic chip, this nanomaterial enables the precise and concurrent measurement of PSA, alongside two complementary PCa biomarkers, matrix metalloproteinase-2 (MMP-2) and anti-α-methylacyl-CoA racemase (anti-AMACR) in diluted human plasma, offering a comprehensive approach to PSA analysis. Taking advantage of the localized surface plasmon resonance principle, this biosensor offers robustness and sensitivity in real sample analysis without the need for labeling agents. With the limit of detection at 0.22, 0.37, and 0.18 ng/mL for PSA, MMP-2, and anti-AMACR, respectively, this biosensing platform holds promise for point-of-care analysis, underscoring its potential impact on medical diagnostics.

Experimental study on ultra-high sensitivity gold-based SPR sensor for refractive index and temperature measurement

We have experimentally demonstrated an ultra-high sensitivity gold-based fiber refractive index (RI) sensor whose main structure is composed of multimode fiber (MMF) and photonic crystal fiber (PCF). The gold film is deposited on V-shaped PCF by magnetron sputtering, and sensing experiments are performed based on the principle of surface plasmon resonance (SPR). Numerical simulation results indicate that the cladding mode of the V-shaped PCF is more capable of stimulating the SPR effect than the core mode. The experimental results show that the RI measurement range of the sensor is 1.333–1.421, with a maximum sensitivity of 10015 nm/RIU. In addition to RI sensing, sensing probes can be coated with polydimethylsiloxane (PDMS) on a gold film for temperature sensing. For temperature detection, the range is from 10 to 100 °C and the maximum sensitivity is 3.5 nm/℃. Besides high sensitivity in RI measurement, the proposed sensor also has good sensing performance in temperature sensing. With the advantages of high sensitivity, good stability, and easy preparation, this sensor has become an important reference in the field of high-performance sensing.

Unraveling the Dynamics of SARS-CoV-2 Mutations: Insights from Surface Plasmon Resonance Biosensor Kinetics.

Surface Plasmon Resonance (SPR) technology is known to be a powerful tool for studying biomolecular interactions because it offers real-time and label-free multiparameter analysis with high sensitivity. This article summarizes the results that have been obtained from the use of SPR technology in studying the dynamics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mutations. This paper will begin by introducing the working principle of SPR and the kinetic parameters of the sensorgram, which include the association rate constant (ka), dissociation rate constant (kd), equilibrium association constant (KA), and equilibrium dissociation constant (KD). At the end of the paper, we will summarize the kinetic data on the interaction between angiotensin-converting enzyme 2 (ACE2) and SARS-CoV-2 obtained from the results of SPR signal analysis. ACE2 is a material that mediates virus entry. Therefore, understanding the kinetic changes between ACE2 and SARS-CoV-2 caused by the mutation will provide beneficial information for drug discovery, vaccine development, and other therapeutic purposes.

Temperature and salinity sensing characteristics of embedded core optical fiber based on surface plasmon resonance

An embedded core fiber sensor based on surface plasmon resonance (SPR) principle is developed. In the structure of optical fiber, the middle of the optical fiber cladding is hollowed out. The hollowed-out part is then filled with a temperature-sensitive layer. For the temperature sensitive layer, polydimethylsiloxane(PDMS) is chosen. A metal layer is placed outside the cladding of the optical fiber to detect changes in the external environment and stimulate the SPR effect.The gold metal(Au) layer is also placed between the cladding and the PDMS to stimulate the SPR effect.The refractive index of seawater varies with salinity and temperature through COMSOL Multiphysics finite element simulation. We can measure the two parameters of salinity and temperature at the same time based on the SPR principle. The sensitivity of salinity and temperature calculated by this sensor is 0.193 nm/%, 0.397 nm/°C. Fiber optic sensors use the SPR principle to detect dynamic, real-time, continuous processes. The measurement range is very wide, and the brightness is also very high.Compared with single-channel measurement of single parameter, this sensor can greatly improve the efficiency of two-parameter measurement. The sensor has the advantages of simple structure, low production cost and high sensitivity, which can realize the simultaneous measurement of two parameters and avoid the crosstalk between parameters. It has great research significance.

Plasmonic Nanostructure Biosensors: A Review.

Plasmonic nanostructure biosensors based on metal are a powerful tool in the biosensing field. Surface plasmon resonance (SPR) can be classified into localized surface plasmon resonance (LSPR) and propagating surface plasmon polariton (PSPP), based on the transmission mode. Initially, the physical principles of LSPR and PSPP are elaborated. In what follows, the recent development of the biosensors related to SPR principle is summarized. For clarity, they are categorized into three groups according to the sensing principle: (i) inherent resonance-based biosensors, which are sensitive to the refractive index changes of the surroundings; (ii) plasmon nanoruler biosensors in which the distances of the nanostructure can be changed by biomolecules at the nanoscale; and (iii) surface-enhanced Raman scattering biosensors in which the nanostructure serves as an amplifier for Raman scattering signals. Moreover, the advanced application of single-molecule detection is discussed in terms of metal nanoparticle and nanopore structures. The review concludes by providing perspectives on the future development of plasmonic nanostructure biosensors.

SPP excitation and coupling mechanism based onmicro/nano fibers.

A hot trend in the development of optoelectronic devices is how to use the principle of surface plasmon resonance to enhance the performance of integrated photonics devices and achieve miniaturization. This paper proposes an accompanying waveguide coupling structure of micro/nano fibers, which consists of two parallel-placed micro/nano fibers (MNFs) coated with a silver film in the waist region and infused with a refractive index matching oil. In the overlapping region, there exists a segment of surface plasmon polaritons (SPPs) coupling area. The excitation and coupling characteristics of SPPs are studied through numerical simulation. Optimal coupling enhancement configuration is obtained by studying variables such as spacing distance, coupling length, and metal film thickness. A comparison is made with the SPP intensity of a single MNF, showing a 220% increase in electric field intensity, demonstrating its excellent coupling effect. By using this coupling structure, exploration of SPPs excitation and coupling mechanisms is enhanced, and structures resembling interferometric devices can be designed, providing new insights for high-performance miniaturized devices.

Agricultural soil health monitoring using photonic crystal fiber based on combined principles of surface plasmon resonance and interferometry for lead ion detection

Agricultural soil health monitoring using photonic crystal fiber based on combined principles of surface plasmon resonance and interferometry for lead ion detection

Au-TiO2 Coated Photonic Crystal Fiber Based SPR Refractometric Sensor for Detection of Cancerous Cells.

A surface plasmon resonance (SPR) refractometric sensor based on gold (Au) and titanium dioxide (TiO2) coated Photonic Crystal Fiber (PCF) is presented for the quick detection of various types of cancerous cells. The cancerous cells and their corresponding normal cells are both considered to be liquid cells each with their unique refractive index (RI). Normally these cells are found in liquid form in the suitable media (food) required to live the cancerous/normal cell lines. Also in our detection case, liquid samples are easy to pump into the sensing channel of the proposed PCF by employing either pressure or capillary forces.The proposed PCF sensor works on the SPR principle, with the Au coating serving as the plasmonic material. This sensor is investigated using the COMSOL Multiphysics software computational tool that is based on the full-vector finite element method (FEM). A TiO2 coating has been applied to enhance adhesion between the Au layer and the PCF surface. Above the Au coating, cancerous cells samples are filled into the PCF. When the core mode of the PCF is coupled with the surface plasmon polariton (SPP) mode under the specific resonance circumstances, SPR will occur on the interface of the gold-sample cell, and in the core mode, the loss peak is observed at the resonance wavelength. Cancerous cells samples have a distinct loss peak than normal cells samples therefore the cancerous cells can be diagnosed by measuring the shift in resonance wavelength corresponding to the loss peak of cancerous and their normal cells samples. The proposed sensor may identify various cancerous cells such as MDAMB-231, MCF-7, PC12, HeLa, and Jurkat for the diagnosis of breast cancer type-1, breast cancer type-2, adrenal glands, cervical, and blood cancer respectively. The computed wavelengths sensitivities of the proposed PCF are 9428.57nm/RIU, 10714.28nm/RIU, 7571.43nm/RIU, 5500nm/RIU, and 6000nm/RIU for the MDAMB-231, MCF-7, PC12, HeLa, and Jurkat cancerous cells, respectively. However, for various cancerous cells, the maximum amplitude sensitivity varies from -1387 RIU-1 to -1599 RIU-1. Moreover, the sensor resolution ranges between 0.93 ×10-5 RIU and 1.82 ×10-5 RIU with a 0.024 maximum detection limit. Because of its improved sensing capability, the presented SPR refractometric sensor is appropriate for the early detection of cancerous cells.

All-Fiber SPR Microfluidic Chip for Arctigenin Detection

The study of active compounds of traditional Chinese medicine (TCM) is an important composition of the modernization of traditional Chinese medicine. However, most of the traditional Chinese medicine active ingredient detection equipment has the problems of large volume and poor flexibility. This paper proposes an all-fiber microfluidic chip based on the principle of surface plasmon resonance (SPR) for arctigenin detection, reducing the diameter of the active ingredient sensor of traditional Chinese medicine to 125 μm. We used capillary fiber as the microfluidic channel, constructed the SPR sensing zone on the inner wall of the capillary fiber, and fixed the target protein on the surface of the sensing zone. We realized the specific detection of arctigenin, with the detection sensitivity of 0.205 nm/(μg/mL) and the limit of detection (LOD) of 0.49 μg/mL. We also verified the specific detection effect of the microfluidic chip in mixed solution. In conclusion, we proposed a kind of all-fiber microfluidic chip with small size, flexibility and real-time specificity detection, which provides a new solution for miniaturization, flexibility and rapid detection of active molecules in TCM detection devices.

Design and analysis of Micro-channelled Quasi D-shape optical Fiber plasmonic Sensor

This study reports on numerical investigation carried out over a newly designed open micro-channel incorporated, side polished single mode fiber (SMF) based plasmonic sensor. The proposed sensor operates on the principle of surface plasmon resonance (SPR) phenomenon to enhance the sensing performance. The commercially available COMSOL Multiphysics software tool is used to design sensor and finite element method (FEM) is used for numerical investigation. From the detail study, an average sensitivity of 1757 nm/RIU (refractive index unit) is obtained with a nanoscale gold strip for wide range of analyte RIs from 1.33 to 1.38. Result indicates that the fabricated sensor can be effectively used in RI measurement of the various fields involving chemical and biological sensing.

Molecularly Imprinted Surface Plasmon Resonance Sensor-Based Devices for Clinical Applications

In clinical applications, surface plasmon resonance sensors are widely used with many advantages including rapid and simultaneous response, high selective, sensitivity and specificity, portable and outstanding detection performance. Recently, the innovations and efforts in the field of sensor have expanded rapidly and have a wide range of applications, especially in the fields of environmental, medical, and pharmaceutical applications, and food safety. In particular, sensor systems were prepared with molecularly imprinted polymers create selective and specific recognition spaces for template molecules in a polymeric matrix, resulting in an important formation with surface modification techniques. In addition, this method provides a wide scope for imprinting various biomolecules with different three-dimensional structures and physical and chemical properties. Unlike time-consuming and complex surface modification methods, molecular imprinting technology offers sensitive, selective, fast, easy preparation, and use approaches especially for diagnostic, and theranostic applications. In addition, molecularly imprinted polymer-based sensors, with their low cost, reusability, high stability, physical and chemical robustness, have become very attractive methods for clinical applications with their sensitivity to very small structural changes in the structure of biomolecules. This review aims to summarize the molecular imprinting technology, the working principle of surface plasmon resonance (SPR) sensors, SPR sensor studies prepared with molecularly imprinted polymers in the literature and the future outlook of these concepts.

Effect of the Thickness of Nanoscale Layers of the Metal-Dielectric Structure on Its Optical Characteristics

A biosensor is a device which uses a mixture of biological and physicochemical components to detect molecular-level interactions. Essentially, biosensors detect the change in physical properties which occur when an immobilized biological molecule, such as an antibody or a protein, binds to their target analyte. A number of methods have been developed to determine interactions between bioreceptors and their analytes, many of which are based on the principle of Surface Plasmon Resonance, or SPR. The ubiquity of SPR comes from its inherent advantages; it allows real time, highly sensitive monitoring of a wide range of molecular interactions, without the requirement for additional labelling of samples. Surface Plasmon Resonance is caused by the interaction of electromagnetic radiation and the free-flowing cloud of electrons within a metal, a process which induces electromagnetic waves and, under certain conditions, resonance effects. Alterations in the physical conditions at the surface have a significant effect on this resonance, and the detection of these changes form the basis of the SPR biosensor. In the work, the effect of the thickness of the layers of the metal-dielectric structure on its optical characteristics was studied. The simulation was carried out for the Krechman configuration, which is a glass prism on which a multilayer metal-dielectric structure is applied. AuSiO2 was used as a metal-dielectric structure, and a laser beam with a wavelength of 633 nm was used as a source of external electromagnetic radiation. The thickness of the gold film varied from 1 to 60 nanometers. The lowest value of the reflection coefficient is reached at a thickness of 50 nm. The thickness of the silicon dioxide film varied from 1 to 30 nm. When the thickness of the dielectric layer is up to 10 nm, its influence on the optical characteristics is insignificant. Macroscopic values of parameters were used in the study, but it is known that real parameters differ greatly from macroscopic ones. To increase the accuracy of modeling the sensor element in further studies, it will be necessary to take into account dimensional changes in the optical parameters of the nanosized metal component in the structure of the sensor element.

Applications of surface plasmon resonance in biomedicine

As one of optical technique, surface plasmon resonance (SPR) shows a superb interdisciplinary usage for detection. A diverse of different SPR-based biosensors have been constructed and been used for various fields, such as biomedicine, environmental monitoring and food safety. This research outlines the basic concepts, the working principle of SPR and the applications of SPR in biomedicine. In addition, the discovery and development of SPR will be present, as well as the mechanism behind SPR instruments. It will also be examined in detail the application of SPR in drug analysis and early diagnosis of cancer. Some perspectives about the latest research advances and future development areas will also be discussed respectively. The advantages and disadvantages of SPR will be illustrated throughout this work.

PCF based surface plasmon resonance temperature sensor with ultrahigh sensitivity

A simple photonic crystal fiber (PCF) temperature sensor with high sensitivity based on the principle of surface plasmon resonance (SPR) is proposed. The cladding of the sensor is mainly composed of two layers of square arranged holes. The inner wall of the outer air holes is selectively plated with gold film, and the outer holes are filled with the temperature sensitive material chloroform to promote the coupling of the surface plasmon mode and the fundamental mode, thereby improving the sensitivity. The finite element method is used to analyze the effects of the temperature on the performance of the sensor. Through tailoring the structural parameters, it is shown that the maximum sensitivity of the sensor can reach up to − 10.4 nm/℃ in the range of 0–60 ℃ with high resolution and good linearity. Such appealing characteristics make the sensor be one of the important potential candidates in the field of temperature sensing.

Exploration on Structural and Optical Properties of Nanocrystalline Cellulose/Poly(3,4-Ethylenedioxythiophene) Thin Film for Potential Plasmonic Sensing Application

There are extensive studies on the development of composite solutions involving various types of materials. Therefore, this works aims to incorporate two polymers of nanocrystalline cellulose (NCC) and poly(3,4-ethylenethiophene) (PEDOT) to develop a composite thin film via the spin-coating method. Then, Fourier transform infrared (FTIR) spectroscopy is employed to confirm the functional groups of the NCC/PEDOT thin film. The atomic force microscopy (AFM) results revealed a relatively homogeneous surface with the roughness of the NCC/PEDOT thin film being slightly higher compared with individual thin films. Meanwhile, the ultraviolet/visible (UV/vis) spectrometer evaluated the optical properties of synthesized thin films, where the absorbance peaks can be observed around a wavelength of 220 to 700 nm. An optical band gap of 4.082 eV was obtained for the composite thin film, which is slightly lower as compared with a single material thin film. The NCC/PEDOT thin film was also incorporated into a plasmonic sensor based on the surface plasmon resonance principle to evaluate the potential for sensing mercury ions in an aqueous medium. Resultantly, the NCC/PEDOT thin film shows a positive response in detecting the various concentrations of mercury ions. In conclusion, this work has successfully developed a new sensing layer in fabricating an effective and potential heavy metal ions sensor.

Surface plasmon resonance: An innovative method for studying water permeability of plant cuticles

The cuticle forms an effective barrier protecting plants from water loss. Its permeability to water and other compounds significantly differs between species, types of cuticle (stomatous, astomatous), and can be affected by a wide variety of ambient conditions. Enzymatic isolation of the leaf cuticle allows obtaining intact cuticles for permeability measurements. However, the most available gravimetric method, which is used for the assessment of water permeability of isolated cuticles, requires a relatively large area of the cuticle and does not allow the determination of membrane heterogeneity. We propose a new method for the determination of water permeance based on an on-line detection of water flux from a liquid phase to the atmosphere through isolated leaf cuticles in semi-flow chambers. This approach is new in using the phenomenon of surface plasmon resonance for the detection of the liquid phase refractive index affected by water vapor. Isolated cuticles of the leaves of Ficus elastica and an artificial polyethersulfone membrane were used for method evaluation. The composition of cuticular wax and its influence on cuticular permeability was also studied. It has been confirmed that the application of the surface plasmon resonance principle can be used for the assessment of leaf cuticle water permeability and heterogeneity.

2D Nanomaterial-Based Surface Plasmon Resonance Sensors for Biosensing Applications.

The absorption and binding energy of material plays an important role with a large surface area and conductivity for the development of any sensing device. The newly grown 2D nanomaterials like black phosphorus transition metal dichalcogenides (TMDCs) or graphene have excellent properties for sensing devices’ fabrication. This paper summarizes the progress in the area of the 2D nanomaterial-based surface plasmon resonance (SPR) sensor during last decade. The paper also focuses on the structure of Kretschmann configuration, the sensing principle of SPR, its characteristic parameters, application in various fields, and some important recent works related to SPR sensors have also been discussed, based on the present and future scope of this field. The present paper provides a platform for researchers to work in the field of 2D nanomaterial-based SPR sensors.

An ultrahighly sensitive photonic crystal fiber based surface plasmon resonance sensor

A photonic crystal fiber (PCF) sensor based on the principle of surface plasmon resonance (SPR) is proposed. Only gold is chosen as the plasmaonic material to deposit on the surface of PCF, greatly simplifying the manufacturing process. The properties of the sensor are numerically investigated by the finite element method (FEM). The effects of the gold layer, the air hole size and the analyte refractive index (RI) of the sensor on the sensing performance are analyzed in detail. The results show that the sensor has an ultrahigh sensitivity of 21,200 nm/RIU and ultrahigh resolution of 4.72 × 10−6RIU in the refractive index range of 1.39–1.43, which can find potential applications in biochemical and biological detection applications

Design and Optimization of Sensing Layer for Terminal Reflective SPR Optical Fiber Hydrogen Sensor

Based on the principle of surface plasmon resonance(SPR), the terminal reflective optical fiber hydrogen sensor structure has been obtained. By simulating, gold is selected as plasma coating material. The performance of the sensor of has been further studied with different thickness of gold film and hydrogen sensitive film. This work can provide theory support for the design of optical fiber surface plasmon resonance hydrogen sensor.

Determination of CRP Autoantibodies by SPR Immunoassay.

Biosensors based on the principle of surface plasmon resonance (SPR) are surface-sensitive optical devices used for monitoring biomolecular interactions at the sensor surface in real time without any labeling. It is used in a wide variety of areas including proteomics, clinical diagnosis, environmental monitoring, drug discovery, and food analysis. C-reactive protein (CRP) is a marker of inflammation, which undergoes conformation changes in local lesions, leading to the formation of mCRP. Autoantibodies against mCRP are frequently detected in systemic lupus erythematosus (SLE) and associated with disease activity and prognosis. An SPR immunoassay for CRP autoantibodies at complement factor H-CRP interface is described in this chapter.