Enhanced sensitivity of fiber SPR sensor by metal nanoparticle

Sensor Review ◽  
2020 ◽  
Vol 40 (3) ◽  
pp. 355-361 ◽  
Author(s):  
Chunlan Liu ◽  
Yang Gao ◽  
YaChen Gao ◽  
Yong Wei ◽  
Ping Wu ◽  
...  
Keyword(s):  
Refractive Index ◽  
Metal Nanoparticles ◽  
Dynamic Range ◽  
Cone Angle ◽  
Fiber Surface ◽  
Metal Nanoparticle ◽  
Surface Plasma Resonance ◽  
Content Type ◽  
Spr Sensor ◽  
Enhanced Sensitivity

Purpose This paper aims to clarify the relationship between the performance of the metal nanoparticles and the sensitivity of the fiber surface plasma resonance (SPR) sensor. It proposes modeling the sensing effects of a single-mode fiber SPR sensor with a cone angle structure decorated with metal nanoparticles. This study uses the metal nanoparticles to the realize enhanced sensitivity of refractive index sensing. Design/methodology/approach This paper opted for an exploratory study using a simulation approach of finite-difference time-domain (FDTD). Specifically, the effect of size, the material and the shape of the metal nanoparticle on sensing performance are investigated theoretically. Findings In conclusion, it is evident that the localized SPR (LSPR) effect weakens as the diameter of the gold nanosphere increases, the SPR effect enhances and the SPR sensitivity increases first and then decreases. The metal nanoparticle with the different materials and different shapes also have different LSPR and SPR sensitivity and wavelength length dynamic range. The investigation shows that, by changing parameters, the reflection spectra of the fiber SPR sensor exhibit an obvious transition from LSPR to SPR characteristics, and enhanced sensitivity of the refractive index is realized. Originality/value This paper fulfills an identified need to study how the sensitivity of the fiber SPR sensor can be enhanced by the metal nanoparticle. After the optimization of parameters, the sensitivity of 5,140 nm/RIU is achieved, which provides a new research direction for sensitivity enhancement of fiber SPR sensor.

scholarly journals Enhanced Sensitivity and Detection of Near-Infrared Refractive Index Sensor with Plasmonic Multilayers

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7056
Author(s):  
Tan Tai Nguyen ◽  
Nguyen Van Sau ◽  
Quang Minh Ngo ◽  
Gauthier Eppe ◽  
Ngoc Quyen Tran ◽  
...  
Keyword(s):  
Refractive Index ◽  
Near Infrared ◽  
High Sensitivity ◽  
Dielectric Films ◽  
Silver Layer ◽  
Refractive Index Sensor ◽  
Detection Accuracy ◽  
Spr Sensor ◽  
Enhanced Sensitivity ◽  
Sensor Sensitivity

In this work, the multilayer of the surface plasmon resonance (SPR) sensor was optimized to achieve the maximum sensor sensitivity. By optimizing the thickness of the silver layer (Ag) and dielectric films (TiO2 and AlAs), the optimum sensitivity of the SPR sensor could be obtained. The performance of the SPR sensor proposed was compared with control simulations utilizing zinc oxide (ZnO) and molybdenum oxide (MoO3). The numerical results indicate that the figure-of-merits (FOM) of the SPR sensor was achieved around 150/RIU, corresponding to the sensor sensitivity of 162.79°/RIU with the optimized thicknesses of the TiO2, Ag, and AlAs layers of 140 nm, 60 nm, and 25 nm, respectively. This refractive index sensor shows the FOM to have high detection accuracy and high sensitivity that lead to finding potential application in bio-chemical detection with a small volume of liquid used in biological diagnosis.

Research on the performance of a novel SPR sensor based on graded index multimode fiber

Sensor Review ◽  
2019 ◽  
Vol 39 (3) ◽  
pp. 358-363 ◽  
Author(s):  
Chunlan Liu ◽  
Yong Wei ◽  
Yudong Su ◽  
Hao Liu ◽  
Yonghui Zhang ◽  
...  
Keyword(s):  
Film Thickness ◽  
Dynamic Range ◽  
Gold Film ◽  
Incident Angle ◽  
Resonance Wavelength ◽  
Multimode Fiber ◽  
Content Type ◽  
Graded Index ◽  
Spr Sensor ◽  
Multichannel Detection

Purpose This paper aims to propose and demonstrate a novel surface plasmon resonance (SPR)-sensing approach by using the fundamental mode beam based on a graded index multimode fiber (GIF). The proposed SPR sensor has high sensitivity and controllable working dynamic range, which expects to solve the two bottlenecks of fiber SPR sensor, including low sensitivity and the difficulty in multichannel detection. Design/methodology/approach The low-order mode of the GIF to SPR sense, which keeps the sensitivity advantage of the single-mode fiber SPR sensor, is used. By using this new SPR sensor, the effect of light incident angle and gold film thickness on working dynamic range was studied. According to the study results, the smaller is the incident angle, the larger is the SPR working dynamic range and the longer is the resonance wavelength with a fixed gold film thickness; the larger is the gold film thickness, the longer is the resonance wavelength with a fixed grinding angle. After the parameter optimization, the sensitivity of these two parameter-adjusting methods reach 4,442 and 3031 nm/RIU. Originality/value When the grinding angle of the GIF increases, the dynamic range of the resonance wavelength increases and has a redshift, sensitivity increases, and the resonance valley becomes more unobvious with a fixed gold film thickness. Similarly, when gold film thickness increases, the dynamic range of the resonance wavelength increases and has a redshift, sensitivity increases, and the resonance valley becomes more unobvious with a fixed grinding angle. These adjusting performance aforementioned lay the foundation for solving of the fiber-based SPR multichannel detection and increasing of the fiber-based SPR sensor sensitivity, which has a good application value.

scholarly journals Comparison of Metal Nanoparticles (Au, Ag, Eu, Cd) Used for Immunoanalysis Using LA-ICP-MS Detection

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 630
Author(s):  
Marcela Vlcnovska ◽  
Aneta Stossova ◽  
Michaela Kuchynka ◽  
Veronika Dillingerova ◽  
Hana Polanska ◽  
...  
Keyword(s):  
Metal Nanoparticles ◽  
Inductively Coupled Plasma ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
P53 Protein ◽  
Metal Nanoparticle ◽  
Biogenic Elements ◽  
Dot Blot ◽  
Icp Ms ◽  
Wide Range

Immunochemical methods are used not only in clinical practice for the diagnosis of a wide range of diseases but also in basic and advanced research. Based on the unique reaction between the antibody and its respective antigens, it serves to specifically recognize target molecules in biological complex samples. Current methods of labelling antibodies with elemental labels followed by detection by inductively coupled plasma mass spectrometry (ICP-MS) allow detection of multiple antigens in parallel in a single analysis. Using the laser ablation (LA) modality (LA-ICP-MS), it is also possible to monitor the spatial distribution of biogenic elements. Moreover, the employment of metal nanoparticle-labeled antibodies expands the applicability also to molecular imaging by LA-ICP-MS. In this work, conjugates of model monoclonal antibody (DO-1, recognizing p53 protein) with various metal nanoparticles-based labels were created and utilized in dot-blot analysis in order to compare their benefits and disadvantages. Based on experiments with the p53 protein standard, commercial kits of gold nanoparticles proved to be the most suitable for the preparation of conjugates. The LA-ICP-MS demonstrated very good repeatability, wide linear dynamic range (0.1–14 ng), and limit of detection was calculated as a 1.3 pg of p53 protein.

Study on the sensitivity enhancement of fiber SPR sensor by gold nanorods

Sensor Review ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rui Wang ◽  
Chunlan Liu ◽  
Yong Wei ◽  
Yudong Su
Keyword(s):  
Refractive Index ◽  
Parameter Optimization ◽  
Gold Nanorods ◽  
Sensitivity Enhancement ◽  
Gold Nanorod ◽  
Enhancement Effect ◽  
Content Type ◽  
Spr Sensor ◽  
Aspect Ratios ◽  
Validation Experiments

Purpose This paper aims to study the sensitivity enhancement effect of the gold nanorod on fiber surface plasmon resonance (SPR) sensor. It proposes modeling the sensing effects of fiber SPR sensor decorated with metal nanoparticles. By using simulation and experiment, the sensitivity enhancement effect of the gold nanorod was studied and demonstrated. Design/methodology/approach The paper opted for an exploratory study using simulation approach of finite-difference time-domain. Specifically, the effect of ratios and aspect ratios of gold nanorod on sensing performance are investigated theoretically. Based on the mathematical models, the validation experiments by using the gold nanorod with the aspect ratios of 5.1 were done to verify the sensitivity enhancement effect of the gold nanorod. Findings In conclusion, it is evident that with the increases of the aspect ratios, the sensing sensitivity of the refractive index increases first, then gradually stabilizes or decreases. After parameter optimization, the ratios and aspect ratios of gold nanorod are chosen to be 8 nm and 12.5, respectively, which makes the optimal refractive index sensitivity of 4465.53 nm/RIU be realized. In addition, the validation experiments by using the gold nanorod with the aspect ratios of 5.1 verify the sensitivity enhancement effect of the gold nanorods. Originality/value This paper proposes and demonstrates a new method for the sensitivity enhancement of fiber SPR sensor. After parameter optimization, the maximum sensitivity of 4465.53 nm/RIU was achieved by using 8 nm gold nanorods with the aspect ratios of 12.5. To verify the sensitivity enhancement of the gold nanorods, the authors also did the validation experiments. The testing results indicated that after the decoration of the gold nanorods, the sensitivity of the sensing probe increases from 2190.57 nm/RIU to 2693.24 nm/RIU, which demonstrates the sensitivity enhancement effect of the gold nanorods.

scholarly journals Critical angle reflection imaging for quantification of molecular interactions on glass surface

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guangzhong Ma ◽  
Runli Liang ◽  
Zijian Wan ◽  
Shaopeng Wang
Keyword(s):  
Refractive Index ◽  
Small Molecule ◽  
Molecular Interactions ◽  
Glass Surface ◽  
Critical Angle ◽  
Dynamic Range ◽  
Refractive Index Change ◽  
Label Free ◽  
Index Change ◽  
Sensing Range

AbstractQuantification of molecular interactions on a surface is typically achieved via label-free techniques such as surface plasmon resonance (SPR). The sensitivity of SPR originates from the characteristic that the SPR angle is sensitive to the surface refractive index change. Analogously, in another interfacial optical phenomenon, total internal reflection, the critical angle is also refractive index dependent. Therefore, surface refractive index change can also be quantified by measuring the reflectivity near the critical angle. Based on this concept, we develop a method called critical angle reflection (CAR) imaging to quantify molecular interactions on glass surface. CAR imaging can be performed on SPR imaging setups. Through a side-by-side comparison, we show that CAR is capable of most molecular interaction measurements that SPR performs, including proteins, nucleic acids and cell-based detections. In addition, we show that CAR can detect small molecule bindings and intracellular signals beyond SPR sensing range. CAR exhibits several distinct characteristics, including tunable sensitivity and dynamic range, deeper vertical sensing range, fluorescence compatibility, broader wavelength and polarization of light selection, and glass surface chemistry. We anticipate CAR can expand SPR′s capability in small molecule detection, whole cell-based detection, simultaneous fluorescence imaging, and broader conjugation chemistry.

scholarly journals Engineering Cyanobacterial Cell Morphology for Enhanced Recovery and Processing of Biomass

2017 ◽  
Vol 83 (9) ◽  
Author(s):  
Adam Jordan ◽  
Jenna Chandler ◽  
Joshua S. MacCready ◽  
Jingcheng Huang ◽  
Katherine W. Osteryoung ◽  
...  
Keyword(s):  
Cell Division ◽  
Cell Morphology ◽  
Dynamic Range ◽  
Enhanced Recovery ◽  
Downstream Processing ◽  
Crop Species ◽  
Content Type ◽  
Alternative Crop ◽  
Cell Harvesting ◽  
Broad Dynamic Range

ABSTRACT Cyanobacteria are emerging as alternative crop species for the production of fuels, chemicals, and biomass. Yet, the success of these microbes depends on the development of cost-effective technologies that permit scaled cultivation and cell harvesting. Here, we investigate the feasibility of engineering cell morphology to improve biomass recovery and decrease energetic costs associated with lysing cyanobacterial cells. Specifically, we modify the levels of Min system proteins in Synechococcus elongatus PCC 7942. The Min system has established functions in controlling cell division by regulating the assembly of FtsZ, a tubulin-like protein required for defining the bacterial division plane. We show that altering the expression of two FtsZ-regulatory proteins, MinC and Cdv3, enables control over cell morphology by disrupting FtsZ localization and cell division without preventing continued cell growth. By varying the expression of these proteins, we can tune the lengths of cyanobacterial cells across a broad dynamic range, anywhere from an ∼20% increased length (relative to the wild type) to near-millimeter lengths. Highly elongated cells exhibit increased rates of sedimentation under low centrifugal forces or by gravity-assisted settling. Furthermore, hyperelongated cells are also more susceptible to lysis through the application of mild physical stress. Collectively, these results demonstrate a novel approach toward decreasing harvesting and processing costs associated with mass cyanobacterial cultivation by altering morphology at the cellular level. IMPORTANCE We show that the cell length of a model cyanobacterial species can be programmed by rationally manipulating the expression of protein factors that suppress cell division. In some instances, we can increase the size of these cells to near-millimeter lengths with this approach. The resulting elongated cells have favorable properties with regard to cell harvesting and lysis. Furthermore, cells treated in this manner continue to grow rapidly at time scales similar to those of uninduced controls. To our knowledge, this is the first reported example of engineering the cell morphology of cyanobacteria or algae to make them more compatible with downstream processing steps that present economic barriers to their use as alternative crop species. Therefore, our results are a promising proof-of-principle for the use of morphology engineering to increase the cost-effectiveness of the mass cultivation of cyanobacteria for various sustainability initiatives.

Experimental and theoretical study of the characteristics of LSPR peaks for metal NPs produced by controlling Ar ambient gas pressure to enhance the efficiency of solar cells

2021 ◽  
pp. 1-6
Author(s):  
Serap Yiğit Gezgin ◽  
Abdullah Kepceoğlu ◽  
Hamdi Şükür Kiliç
Keyword(s):  
Metal Nanoparticles ◽  
Ag Nanoparticles ◽  
Solar Spectrum ◽  
Wavelength Region ◽  
Gas Pressure ◽  
Metal Nanoparticle ◽  
Ag Nanoparticle ◽  
Extinction Cross Section ◽  
Ambient Gas ◽  
Ar Gas

In this study, silver (Ag) nanoparticle thin films were deposited on microscope slide glass and Si wafer substrates using the pulsed-laser deposition (PLD) technique in Ar ambient gas pressures of 1 × 10−3 and 7.5 × 10−1 mbar. AFM analysis has shown that the number of Ag nanoparticles reaching the substrate decreased with increasing Ar gas pressure. As a result of Ar ambient gas being allowed into the vacuum chamber, it was observed that the size and height of Ag nanoparticles decreased and the interparticle distances decreased. According to the absorption spectra taken by a UV–vis spectrometer, the wavelength where the localised surface plasmon resonance (LSPR) peak appeared was shifted towards the longer wavelength region in the solar spectrum as Ar background gas pressure was decreased. This experiment shows that LSPR wavelength can be tuned by adjusting the size of metal nanoparticles, which can be controlled by changing Ar gas pressure. The obtained extinction cross section spectra for Ag nanoparticle thin film was theoretically analysed and determined by using the metal nanoparticle–boundary element method (MNPBEM) toolbox simulation program. In this study, experimental spectrum and simulation data for metal nanoparticles were acquired, compared, and determined to be in agreement.

scholarly journals Optimization of transition metal nanoparticle-phosphonium ionic liquid composite catalytic systems for deep hydrogenation and hydrodeoxygenation reactions

2015 ◽  
Vol 17 (3) ◽  
pp. 1597-1604 ◽  
Author(s):  
Abhinandan Banerjee ◽  
Robert W. J. Scott
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Transition Metal ◽  
Metal Nanoparticles ◽  
Metal Nanoparticle ◽  
Catalytic Systems ◽  
Phosphonium Ionic Liquid

Stable metal nanoparticles in tetraalkylphosphonium ionic liquids can catalyze hydrogenations, as well as phenol hydrodeoxygenation, owing to presence of adventitious borates.

Sign in / Sign up

Export Citation Format

Share Document