High Sensitivity Surface Plasmon Research Articles

Sensitivity-enhanced plasmonic sensor modified with ZIF-8

ZIF-8 is a typical metal–organic framework (MOF) material, which has great potential for sensor improvement. In this paper, we prepared a high sensitivity surface plasmon resonance (SPR) sensor based on ZIF-8/Au and described the preparation process of the sensor and characterized the samples in detail. The results showed that the synthesized ZIF-8 nanoparticles were uniform with an average diameter of about 50 nm. The performance of the sensor was related to the amount of ZIF-8, which could be controlled by adjusting the number of spin-coating cycles. When the refractive index ranged from 1.3335 to 1.3635, the maximum sensitivity of the sensor reached 3961.36nm/RIU with one cycle of spin-coating, which was 74.05% higher than that of pure Au single-layer film sensor. Furthermore, the feasibility of the proposed sensor for biological sensing was demonstrated by detecting bovine serum albumin (BSA).

Design and Development of High Sensitive Surface Plasmon Resonance Biosensors for Glucose Detection

Design and Development of High Sensitive Surface Plasmon Resonance Biosensors for Glucose Detection

High-sensitive surface plasmon resonance sensor for melamine detection in dairy products based on graphene oxide /chitosan nanocomposite

Accurate diagnosis and determination of the appropriate dose of melamine is crucial, especially in children's food, due to the potential for severe side effects such as kidney stones. This research has demonstrated the effectiveness of the graphene oxide-chitosan (GOCS) composite in modifying the gold chip surface as a sensor platform, resulting in a significant 1.17° angular change relative to the bare gold chip for the detection of melamine. The GOCS composite was analyzed using SEM, XRD, and FTIR. The GOCS sensor exhibited high sensitivity with a value of 239.1◦μM−1, a linear range (L.R) of 0.01–200 μM, affinity constant of 1.73 × 104 and an impressive limit of detection (LOD) of 10 nM. These findings highlight the potential of the GOCS sensor for accurately and precisely detecting melamine. Additionally, we compared the obtained results from the sensor with those from the standard method of HPLC, which is referred to as the gold standard in analytical chemistry, by conducting tests using GOCS/Au to identify melamine in commercial samples. The comparison showed that the GOCS sensor offers desirable features for analyzing real samples, making it a promising tool for accurately and efficiently detecting melamine in various samples.

Intensity Interrogation-Based High-Sensitivity Surface Plasmon Resonance Imaging Biosensor for Apoptosis Detection in Cancer.

Intensity interrogation-based surface plasmon resonance imaging (ISPRi) sensing has a simple schematic design and is the most widely used surface plasmon resonance technology at present. In this study, we report the successful development of a novel high-sensitivity ISPRi biosensor and its application for apoptosis detection in cancer cells. By optimizing the excitation wavelength and excitation angle, we achieved a refractive index resolution (RIR) of 5.20 × 10-6 RIU. Importantly, the biosensor has been tested and validated for high-throughput and label-free detection of activated caspase-3 with its specific inhibitor Z-DEVD-FMK in apoptotic cells. Therefore, this study describes a novel molecular imaging system to monitor apoptosis in cancers for disease diagnosis and/or evaluation of therapeutic efficacy of anti-cancer drugs.

Low-loss and high-sensitivity surface plasmon resonance sensor composed of microstructured optical fibers for wide visible-to-infrared and refractive index ranges

ObjectiveOptical fiber sensing technology develops rapidly and is widely used. In order to design a SPR sensor with better performance and easy production, a new type D-MOF sensor with low loss, high sensitivity and simple structure is proposed. MethodsThe full vector finite element method (FEM) was used to optimize the structure parameters by using the multi-physics analysis software COMSOL, and the performance of the structure was systematically analyzed. ResultsThe sensor operational wavelength spans the visible and infrared range (430 nm to 7200 nm). The refractive index detection range of 1.00–1.42, the maximum wavelength sensitivity and the optimal resolution are 60,000 nm/RIU and 1.67 × 10−6 RIU−1, respectively, and the maximum limiting loss peak is 64.99 dB/cm. In addition, MOF-SPR sensors have large tolerance and low sensitivity of structural parameters in actual manufacturing. It has great application potential in biosensing and other fields.

Design and Theoretical Analysis of High-Sensitive Surface Plasmon Resonance Sensor Based on Au/Ti 3C2Tx-MXene Hybrid Layered D-Shaped Photonic Crystal Fiber

To achieve high-sensitive refractive index (RI) sensing, an Au/Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> -MXene hybrid layered D-shaped photonic crystal fiber (PCF) based on surface plasmon resonance (SPR) sensor is proposed theoretically. The cladding of the D-shaped PCF has a hexagonal air-hole arrangement. In addition, the two air holes nearest to the metal layer in the first layer of cladding are reduced to enhance the plasma wave and provide an efficient leakage channel. The two air holes second nearest to the metal layer in the same layer are enlarged to limit the light scattering and guide more energy coupled with the surface plasmon polariton (SPP) mode. A thin layer of the Ti3C2Tx-MXene and Au film is applied on the surface of the D-shaped PCF to produce plasmon resonances across a wide range of wavelengths. By using the finite element method, the optical properties of the proposed PCF-SPR sensor are investigated. The results of the numerical analysis show that this sensor has a significant SPR effect, and the resonance loss peaks can be formed at different positions in the wavelength range of 800-2020 nm. The average RI sensitivity reaches 48120 nm/RIU and the maximum sensitivity is up to 64600 nm/RIU in the refractive index range of 1.390-1.415. The RI sensitivity of the Au/Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> -MXene layered sensor is 2.36 times higher than the sensor with only the Au layer. The proposed structure has its unique sensing properties, which can be effectively applied in bio-sensing fields.

An Ultrasensitive SPR biosensor for RNA detection based on robust GeP5 nanosheets

Ultrasensitive and rapid detection of biomarkers is among the upmost priorities in promoting healthcare advancements. Improved sensitivity of photonic sensors based on two-dimensional (2D) materials have brought exciting prospects for achieving real-time and label-free biosensing at dilute target concentrations. Here, we report a high-sensitivity surface plasmon resonance (SPR) RNA sensor using metallic 2D GeP5 nanosheets as the sensing material. Theoretical evaluations revealed that the presence of GeP5 nanosheets can greatly enhance the plasmonic electric field of the Au film thereby boosting sensing sensitivity, and that optimal sensitivity (146° RIU−1) can be achieved with 3-nm-thick GeP5. By functionalizing GeP5 nanosheets with specific cDNA probes, detection of SARS-CoV-2 RNA sequences were achieved using the GeP5-based SPR sensor, with high sensitivity down to a detection limit of 10 aM and excellent selectivity. This work demonstrates the immense potential of GeP5-based SPR sensors for advanced biosensing applications and paves the way for utilizing GeP5 nanosheets in novel sensor devices.

High Sensitivity Surface Plasmon Resonance Magnetic Field Sensor Based on Au/Gold Nanoparticles/Magnetic Fluid in the Hollow Core Fiber

A type of surface plasmon resonance (SPR) magnetic field sensor based on Au/gold nanoparticles/magnetic fluid (MF)-processed hollow core fiber is proposed in this work, which fully utilizes SPR’s high sensitivity to RI and the magnetron refractive index characteristic of MF. The metal material Au excites SPR and gold nanoparticles excite the localized surface plasmon resonance (LSPR). The coupling of surface plasmon polariton (SPP) with localized surface plasmon (LSP) increases the local electric field strength, thus improving the sensor’s sensitivity. Both the theoretical analysis on the sensing mechanism and the experimental findings demonstrate that this novel SPR magnetic field sensor has a wide measurement range and high sensitivity. In the range of magnetic field strength from 0 to 603 Gs, the sensitivity can reach up to 156 pm/Gs, and the linearity is good (the coefficient of determination is 0.996). Compared with other optical fiber magnetic field sensors, the sensor proposed in this paper has the benefits of easy fabrication, excellent sensitivity, simple structure, strong anti-interference ability, and wide measurement range, exhibiting significant application potentials in the fields of military drills, aerospace, etc.

High-sensitivity surface plasmon resonance refractive index sensor with high resolution based on D-shaped photonic crystal fiber

High-sensitivity surface plasmon resonance refractive index sensor with high resolution based on D-shaped photonic crystal fiber

Sensitivity Enhancement of Surface Plasmon Resonance-based Biosensor using Aluminium-Cobalt-Tungsten Disulfide-Graphene Heterostructure

An attempt has been made to enhance the sensitivity of a high-sensitive surface plasmon resonance (SPR) biosensor with an aluminium-cobalt bimetallic layer covered by a tungsten disulfide-graphene heterostructure. A thin layer of cobalt coated on an aluminium layer contributed substantially to increase the sensor performance. The use of Al and Co metals instead of noble metals like Ag and Au reduced the cost of the sensor. Further, tungsten disulfide (WS2) layers were employed to improve sensitivity and protect the bimetal Al-Co from becoming oxidized, whereas graphene served as the biomolecule trapping medium. The number of WS2 and graphene layers have optimized for better sensitivity. The proposed biosensor Al-Co-WS2-graphene structure displayed an excellent sensitivity of 300°/RIU, convenient for sensing biomolecules.

A High-Sensitivity SPR Sensor Based on MMF-Tapered HCF-MMF Fiber Structure for Refractive Index Sensing

In this article, a high-sensitivity surface plasmon resonance (SPR) sensor based on multimode fiber (MMF)-tapered hollow core fiber (THCF)-MMF structure is fabricated and proposed for refractive index (RI) sensing. As the measurement RI increases, the SPR peak right shifts, a multimode interference (MMI) spectrum will also appear in the visible wavelength in front of the SPR peak, and the MMI resonance wavelength left shifts with the RI increases. The RI changes can be detected by monitoring the resonance wavelength difference between the MMI wavelength and the SPR peak, which is a new method used to measure the RI. The RI sensing performance for the proposed sensor probes with different taper ratios and different HCF core diameters is explored. The experimental results show that the sensitivity could be significantly improved at large RI for the MMF-THCF-MMF probe with a large taper ratio. For the probe with an HCF core diameter of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$30 ~\mu \text{m}$ </tex-math></inline-formula> and a taper ratio of 3.3, a high RI sensitivity of 7592.25 nm/RIU is obtained at the RI of 1.40. The proposed SPR sensor is easily fabricated and has a simple structure, which has potential applications in biochemical sensing fields.

Theoretical and experimental study of a highly sensitive SPR biosensor based on Au grating and Au film coupling structure.

A high-sensitivity surface plasmon resonance (SPR) sensor based on the coupling of Au grating and Au film is investigated through simulations and experiments. The SPR sensor is designed by using a hybrid method composed of genetic algorithm (GA) and rigorous coupled wave analysis (RCWA). The numerical results indicate the sensor has an angular sensitivity of 397.3°/RIU (refractive index unit), which is approximately 2.81 times higher than the conventional Au-based sensor and it is verified by experiments. Theoretical analysis, by finite-difference time-domain (FDTD) method, demonstrates the co-coupling between surface plasmon polaritons (SPPs) propagating on the surface of Au film and localized surface plasmons (LSPs) in the Au grating nanostructure, improving the sensitivity of the SPR sensor. According to the optimized structural parameters, the proposed sensor is fabricated using e-beam lithography and magnetron sputtering. In addition, the proposed sensor is very sensitive to the detection of small molecules. The limit of detection (LOD) for okadaic acid (OA) is 0.72 ng/mL based on an indirect competitive inhibition method, which is approximately 38 times lower than the conventional Au sensor. Such a high-sensitivity SPR biosensor has potential in the applications of immunoassays and clinical diagnosis.

Performance Enhancement of SPR Biosensor Using Graphene-MoS2 Hybrid Structure.

We investigate a high-sensitivity surface plasmon resonance (SPR) biosensor consisting of a Au layer, four-layer MoS2, and monolayer graphene. The numerical simulations, by the transfer matrix method (TMM), demonstrate the sensor has a maximum sensitivity of 282°/RIU, which is approximately 2 times greater than the conventional Au-based SPR sensor. The finite difference time domain (FDTD) indicates that the presence of MoS2 film generates a strong surface electric field and enhances the sensitivity of the proposed SPR sensor. In addition, the influence of the number of MoS2 layers on the sensitivity of the proposed sensor is investigated by simulations and experiments. In the experiment, MoS2 and graphene films are transferred on the Au-based substrate by the PMMA-based wet transfer method, and the fabricated samples are characterized by Raman spectroscopy. Furthermore, the fabricated sensors with the Kretschmann configuration are used to detect okadaic acid (OA). The okadaic acid–bovine serum albumin bioconjugate (OA-BSA) is immobilized on the graphene layer of the sensors to develop a competitive inhibition immunoassay. The results show that the sensor has a very low limit of detection (LOD) of 1.18 ng/mL for OA, which is about 22.6 times lower than that of a conventional Au biosensor. We believe that such a high-sensitivity SPR biosensor has potential applications for clinical diagnosis and immunoassays.

Design of High-Sensitivity Surface Plasmon Resonance Sensor Based on Nanostructured Thin Films for Effective Detection of DNA Hybridization.

As developed countries’ ability to control infectious diseases increases, it has become clear that genetic diseases are a major cause of disability, death, and human tragedy. Coronavirus has recently spread throughout the world, and the capacity to detect low concentrations and virus changes can help to prevent the sickness from spreading further. In this paper, a surface plasmon resonance sensor based on nanostructured thin films and graphene as a 2D material has been designed with high sensitivity and accuracy to identify DNA-based infectious diseases such as SARS-CoV-2. The transfer matrix method assesses the effects of different structural factors, including nanolayer thickness on the sensor’s performance. The results demonstrated that the sensor with the Kretschmann configuration has ultra-high sensitivity (192.19 deg/RIU) and a high figure of merit (634.68 RIU−1).

High sensitivity surface plasmon resonance sensor based on D-shaped high birefringence photonic crystal fibre

A sensitivity refractive index (RI) sensor based on surface plasmon resonance (SPR) effect in D-shaped high birefringence photonic crystal fibre (PCF) is presented and studied by the finite element method (FEM). Through the designing of air holes arrangement in PCF, the birefringence of optical fibre is improved and the SPR effect of y-polarized core mode is directionally excited. The designed D-shaped PCF with gold film in the damaged air holes enhances the interaction of the evanescent field with the external medium. Simulation results indicate that the sensor has a sensing range from 1.30 to 1.37, and the average spectral sensitivity is 10348.3 nm/RIU. The maximum spectral sensitivity of 19,288 nm/RIU and a high resolution of 5.18 × 10−6 RIU can be obtained at 1.37. This high sensitivity sensor has broad application prospects in life science and other research fields.

High Sensitivity Surface Plasmon Resonance Sensor Based on a Ge-Doped Defect and D-Shaped Microstructured Optical Fiber.

In this work a plasmonic sensor with a D-Shaped microstructured optical fiber is proposed to detect a wide range of analyte refractive index by doping the pure silica core with distinct concentrations of Germanium Dioxide , causing the presentation of high spectral sensitivity. In this case, the fiber is shaped by polishing a coating of , on the region that will be doped with , in the polished area, a thin gold layer, which constitutes the plasmonic material, is introduced, followed by the analyte, in a way which the gold layer is deposited between the . and the analyte. The numerical results obtained in the study shows that the sensor can determine efficiently a range of 0.13 refractive index units , with a limit operation where varies from 1.32 to 1.45. Within this application, the sensor has reached an average wavelength sensitivity of up to . With this level of sensitivity, the D-Shaped format and wide range of detection, the proposed fiber has great potential for sensing applications in several areas.

Retrieval of refractive index of ultrafine single particle using hygroscopic growth factor obtained by high sensitive surface plasmon resonance microscopy

When exposed to different relative humidities (RHs), the optical properties of atmospheric aerosols will change because of changes in the aerosol particle size and complex refractive index (RI), which will affect haze formation and global climate change. The potential contributions of ultrafine particles to the atmospheric optical characteristics and to haze spreading cannot be ignored because of their high particle number concentrations and strong diffusibility; measurement of the optical properties of wet ultrafine particles is thus highly important for environmental assessment. Therefore, a surface plasmon resonance microscopy with azimuthal rotation illumination (SPRM-ARI) system is designed to determine the RIs of single particle aerosols with diameters of less than 100 nm in the hygroscopic growth process. Measurements are taken using mixed single particles with different mass ratios. The RIs of mixed single aerosols at different RHs are retrieved by measuring the scattering light intensity using the SPRM-ARI system and almost all the RIs of the bicomponent particles with different mass ratios decrease with increasing water content under high RH conditions. Finally, for each of the bicomponent particles, the maximum standard deviations for the retrieved RI values are only 2.06×10−3, 3.08×10−3 and 3.83×10−3, corresponding to the NaCl and NaNO3 bicomponent particles with a 3:1 mass ratio at 76.0% RH, the NaCl and glucose particles with a 1:3 mass ratio at 89.0% RH, and the NaCl and OA particles with a 1:1 mass ratio at 78.0% RH, respectively; these results indicate that the high-sensitivity SPRM-ARI system can measure the RI effectively and accurately.

Refractive index and temperature dual parameter sensor based on a twin-core photonic crystal fiber

A twin-core photonic crystal fiber sensor is proposed for measuring liquid refractive index (RI) and temperature simultaneously. The air holes of the sensor are arranged in a hexagonal pattern, and two planes are introduced by polishing in the cladding. On one side of the plane, the gold film is deposited for RI measurement, and on the other side, the gold film and polydimethylsiloxane are deposited for temperature measurement. We analyzed its sensing characteristics by using the finite element method. The numerical results show that the two channels for measuring RI and temperature have no mutual interference and the arrangement reduces the complexity of the sensing measurement. The maximum spectral sensitivity of the sensor is 20 000 nm/RIU and 9.2 nm °C−1, respectively, when the liquid RI is in the range of 1.36–1.42 and the temperature is in the range of 0 °C–50 °C. The results also show the sensing accuracy was not very sensitive to the change of structural parameters, which makes the sensor very easy to fabricate. Our work is very helpful for implementation of a high sensitivity, easy fabrication and real-time multi-parameter surface plasmon resonance sensor.

High-sensitivity surface plasmon resonance sensor based on the ten-fold eccentric core quasi-D-shaped photonic quasi-crystal fiber coated with indium tin oxide

The predecessor of China Optics was China Optics and Applied Optics Digest, which was founded in 1985. At that time, it was the only retrieval journal in the field of optics in China. At the end of 2008, China Optics and Applied Optics Digest was renamed

High-Sensitive Surface Plasmon Resonance Imaging Biosensor Based on Dual-Wavelength Differential Method.

Intensity interrogation surface plasmon resonance (ISPR) sensing has a simple schematic design and is the most widely used surface plasmon resonance technology at present. However, it has relatively low sensitivity, especially for ISPR imaging (ISPRi). In this paper, a new technique for the real-time monitoring of biomolecule binding on sensor surfaces via ISPRi detection is described. The technique is based on the interrogation of the differential value of two intensities at two specific wavelengths from the reflected light spectrum. In addition, we also optimized the selection of dual-wavelength parameters under different circumstances to achieve the highest sensitivity. The new technique achieved a refractive index resolution (RIR) of 2.24 × 10–6 RIU, which is far beyond that of traditional ISPRi technique. Moreover, our new ISPRi technique also realized the real-time detection of high-throughput biomolecular binding. This study is expected to promote the development of faster and more accurate SPRi technologies.