Journal articles: 'LSPR sensors'

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Alharbi, Raed, Mehrdad Irannejad, and Mustafa Yavuz. "A Short Review on the Role of the Metal-Graphene Hybrid Nanostructure in Promoting the Localized Surface Plasmon Resonance Sensor Performance." Sensors 19, no. 4 (February 19, 2019): 862. http://dx.doi.org/10.3390/s19040862.

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Localized Surface Plasmon Resonance (LSPR) sensors have potential applications in essential and important areas such as bio-sensor technology, especially in medical applications and gas sensors in environmental monitoring applications. Figure of Merit (FOM) and Sensitivity (S) measurements are two ways to assess the performance of an LSPR sensor. However, LSPR sensors suffer low FOM compared to the conventional Surface Plasmon Resonance (SPR) sensor due to high losses resulting from radiative damping of LSPs waves. Different methodologies have been utilized to enhance the performance of LSPR sensors, including various geometrical and material parameters, plasmonic wave coupling from different structures, and integration of noble metals with graphene, which is the focus of this report. Recent studies of metal-graphene hybrid plasmonic systems have shown its capability of promoting the performance of the LSPR sensor to a level that enhances its chance for commercialization. In this review, fundamental physics, the operation principle, and performance assessment of the LSPR sensor are presented followed by a discussion of plasmonic materials and a summary of methods used to optimize the sensor’s performance. A focused review on metal-graphene hybrid nanostructure and a discussion of its role in promoting the performance of the LSPR sensor follow.

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Lu, Mengdi, Wei Peng, Ming Lin, Fang Wang, and Yang Zhang. "Gold Nanoparticle-Enhanced Detection of DNA Hybridization by a Block Copolymer-Templating Fiber-Optic Localized Surface Plasmon Resonance Biosensor." Nanomaterials 11, no. 3 (March 1, 2021): 616. http://dx.doi.org/10.3390/nano11030616.

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To overcome low surface coverage and aggregation of particles, which usually restricts the sensitivity and resolution of conventional localized surface plasmon resonance (LSPR) fiber-optic sensors, we propose a simple self-assembled templating technique that uses a nanometer thickness block copolymer (BCP) layer of poly(styrene-b-4-vinylpyridine) to form a 33 nm gold nanoparticle (AuNP) monolayer with high uniformity and density for LSPR sensing. The LSPR resonance wavelength for this PS-b-P4VP templated methodology is 592 nm and its refractive index sensitivity is up to 386.36 nm/RIU, both of which are significantly improved compared to those of conventional LSPR techniques. Calibrated by a layer-by-layer polyelectrolyte deposition procedure, the decay length of this LSPR sensor is calculated to be 78 nm, which is lower than other traditional self-assembled LSPR sensors. Furthermore, hybridization between target ssDNA, which is linked with capture ssDNA on the LSPR biosensor and DNA–AuNP conjugates, leads to a low detection limit of 67 pM. These enhanced performances are significant and valuable for high-sensitivity and cost-effective LSPR biosensing applications.

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Alharbi, Raed, and Mustafa Yavuz. "Promote Localized Surface Plasmonic Sensor Performance via Spin-Coating Graphene Flakes over Au Nano-Disk Array." Photonics 6, no. 2 (May 25, 2019): 57. http://dx.doi.org/10.3390/photonics6020057.

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Although localized surface plasmonic resonance (LSPR) sensors have advantages over regular surface plasmonic resonance (SPR) sensors, such as in sensor setup, excitation method, and cost, they suffer from low performance when compared to SPR sensors, which thus limits their commercialization. Among different methods applied to promote LSPR sensor performance, metal-two-dimensional (2D) hybrid nanostructure has been shown to be an efficient improvement. However, metal-2D hybrid nanostructures may come in a complex or a simple scheme and the latter is preferred to avoid challenges in fabrication work and to be applicable in mass production. In this work, a new and simple gold-graphene hybrid scheme is proposed and its plasmonic sensing performance is numerically evaluated using the finite different time domain (FDTD) method. The proposed sensor can be fabricated by growing a Au nano-disk (ND) array on a quartz substrate and then spin-coating graphene flakes of different sizes and shapes randomly on top of and between the Au NDs. Very high sensitivity value is achieved with 2262 nm/RIU at a 0.01 refractive index change. The obtained sensitivity value is very competitive in the field of LSPR sensors using metal-2D hybrid nanostructure. This proposed sensor can be utilized in different biosensing applications such as immunosensors, sensing DNA hybridization, and early disease detection, as discussed at the end of this article.

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Lee, Seunghun, Hyerin Song, Heesang Ahn, Seungchul Kim, Jong-ryul Choi, and Kyujung Kim. "Fiber-Optic Localized Surface Plasmon Resonance Sensors Based on Nanomaterials." Sensors 21, no. 3 (January 26, 2021): 819. http://dx.doi.org/10.3390/s21030819.

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Applying fiber-optics on surface plasmon resonance (SPR) sensors is aimed at practical usability over conventional SPR sensors. Recently, field localization techniques using nanostructures or nanoparticles have been investigated on optical fibers for further sensitivity enhancement and significant target selectivity. In this review article, we explored varied recent research approaches of fiber-optics based localized surface plasmon resonance (LSPR) sensors. The article contains interesting experimental results using fiber-optic LSPR sensors for three different application categories: (1) chemical reactions measurements, (2) physical properties measurements, and (3) biological events monitoring. In addition, novel techniques which can create synergy combined with fiber-optic LSPR sensors were introduced. The review article suggests fiber-optic LSPR sensors have lots of potential for measurements of varied targets with high sensitivity. Moreover, the previous results show that the sensitivity enhancements which can be applied with creative varied plasmonic nanomaterials make it possible to detect minute changes including quick chemical reactions and tiny molecular activities.

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S. S. dos Santos, Paulo, José M. M. M. de Almeida, Isabel Pastoriza-Santos, and Luís C. C. Coelho. "Advances in Plasmonic Sensing at the NIR—A Review." Sensors 21, no. 6 (March 17, 2021): 2111. http://dx.doi.org/10.3390/s21062111.

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Surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR) are among the most common and powerful label-free refractive index-based biosensing techniques available nowadays. Focusing on LSPR sensors, their performance is highly dependent on the size, shape, and nature of the nanomaterial employed. Indeed, the tailoring of those parameters allows the development of LSPR sensors with a tunable wavelength range between the ultra-violet (UV) and near infra-red (NIR). Furthermore, dealing with LSPR along optical fiber technology, with their low attenuation coefficients at NIR, allow for the possibility to create ultra-sensitive and long-range sensing networks to be deployed in a variety of both biological and chemical sensors. This work provides a detailed review of the key science underpinning such systems as well as recent progress in the development of several LSPR-based biosensors in the NIR wavelengths, including an overview of the LSPR phenomena along recent developments in the field of nanomaterials and nanostructure development towards NIR sensing. The review ends with a consideration of key advances in terms of nanostructure characteristics for LSPR sensing and prospects for future research and advances in this field.

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Duan, Qilin, Yineng Liu, Shanshan Chang, Huanyang Chen, and Jin-hui Chen. "Surface Plasmonic Sensors: Sensing Mechanism and Recent Applications." Sensors 21, no. 16 (August 4, 2021): 5262. http://dx.doi.org/10.3390/s21165262.

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Surface plasmonic sensors have been widely used in biology, chemistry, and environment monitoring. These sensors exhibit extraordinary sensitivity based on surface plasmon resonance (SPR) or localized surface plasmon resonance (LSPR) effects, and they have found commercial applications. In this review, we present recent progress in the field of surface plasmonic sensors, mainly in the configurations of planar metastructures and optical-fiber waveguides. In the metastructure platform, the optical sensors based on LSPR, hyperbolic dispersion, Fano resonance, and two-dimensional (2D) materials integration are introduced. The optical-fiber sensors integrated with LSPR/SPR structures and 2D materials are summarized. We also introduce the recent advances in quantum plasmonic sensing beyond the classical shot noise limit. The challenges and opportunities in this field are discussed.

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Yin, Fengyu, Jin Liu, Haima Yang, Aleksey Kudreyko, and Bo Huang. "Design and Optimization of Plasmon Resonance Sensor Based on Micro–Nano Symmetrical Localized Surface." Symmetry 12, no. 5 (May 20, 2020): 841. http://dx.doi.org/10.3390/sym12050841.

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Surface Plasma resonance (SPR) sensors combined with biological receptors are widely used in biosensors. Due to limitations of measurement techniques, small-scale, low accuracy, and sensitivity to the refractive index of solution in traditional SPR prism sensor arise. As a consequence, it is difficult to launch commercial production of SPR sensors. The theory of localized surface plasmon resonance (LSPR) developed based on SPR theory has stronger coupling ability to near-field photons. Based on the LSPR sensing theory, we propose a submicron-sized golden-disk and graphene composite structure. By varying the thickness and diameter of the array disk, the performance of the LSPR sensor can be optimized. A graphene layer sandwiched between the golden-disk and the silver film can prevent the latter from oxidizing. Symmetrical design enables high-low concentration of dual-channel distributed sensing. As the fixed light source, we use a 632.8-nm laser. A golden nano-disk with 45 nm thickness and 70 nm radius is designed, using a finite difference time domain (FDTD) simulation system. When the incident angle is 42°, the figure of merit (FOM) reaches 8826, and the measurable refractive index range reaches 0.2317.

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Proença, Manuela, Marco S. Rodrigues, Diana I. Meira, M. Cidalia R. Castro, Pedro V. Rodrigues, Ana V. Machado, Eduardo Alves, Nuno P. Barradas, Joel Borges, and Filipe Vaz. "Optimization of Au:CuO Thin Films by Plasma Surface Modification for High-Resolution LSPR Gas Sensing at Room Temperature." Sensors 22, no. 18 (September 17, 2022): 7043. http://dx.doi.org/10.3390/s22187043.

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In this study, thin films composed of gold nanoparticles embedded in a copper oxide matrix (Au:CuO), manifesting Localized Surface Plasmon Resonance (LSPR) behavior, were produced by reactive DC magnetron sputtering and post-deposition in-air annealing. The effect of low-power Ar plasma etching on the surface properties of the plasmonic thin films was studied, envisaging its optimization as gas sensors. Thus, this work pretends to attain the maximum sensing response of the thin film system and to demonstrate its potential as a gas sensor. The results show that as Ar plasma treatment time increases, the host CuO matrix is etched while Au nanoparticles are uncovered, which leads to an enhancement of the sensitivity until a certain limit. Above such a time limit for plasma treatment, the CuO bonds are broken, and oxygen is removed from the film’s surface, resulting in a decrease in the gas sensing capabilities. Hence, the importance of the host matrix for the design of the LSPR sensor is also demonstrated. CuO not only provides stability and protection to the Au NPs but also promotes interactions between the thin film’s surface and the tested gases, thereby improving the nanocomposite film’s sensitivity. The optimized sensor sensitivity was estimated at 849 nm/RIU, which demonstrates that the Au-CuO thin films have the potential to be used as an LSPR platform for gas sensors.

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Li, Guoru, Ragini Singh, Jiajun Guo, Bingyuan Zhang, and Santosh Kumar. "Nb₂CT_x MXene-assisted double S-tapered fiber-based LSPR sensor with improved features for tyramine detection." Applied Physics Letters 122, no. 8 (February 20, 2023): 083701. http://dx.doi.org/10.1063/5.0143776.

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Niobium carbide (Nb2CTx), a type of MXene with high optical transparency, large specific surface area, and good electrical conductivity, is expected to perform as an excellent medium in the field of optical fiber biosensing. Here, we fabricated double S-tapered fiber sensors functionalized with gold nanoparticles/graphene oxide/tyrosinase (AuNPs/GO/tyrosinase) and AuNPs/Nb2CTx/tyrosinase, respectively. The double S-tapered structure can provide more evanescent wave leakage and enhance light–matter interaction. By implementing transmittance experiment, the sensitivity of the two probes were tested to be 17 and 34 pm/ μM over 0–300 μM tyramine concentrations. The comparative results demonstrate that Nb2CTx-enhanced localized surface plasmon resonance (LSPR) sensor has more excellent performance due to the existence of surface functional groups and large specific surface area of Nb2CTx. Our work provides a research platform for improving the sensitivity of LSPR sensors.

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Qian, Siyu, Xinlong Chen, Shiyu Jiang, Qiwen Pan, Yachen Gao, Lei Wang, Wei Peng, Shanjun Liang, Jie Zhu, and Shengchun Liu. "Direct detection of charge and discharge process in supercapacitor by fiber-optic LSPR sensors." Nanophotonics 9, no. 5 (February 22, 2020): 1071–79. http://dx.doi.org/10.1515/nanoph-2019-0504.

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AbstractSupercapacitors with high power density, ultralong lifespan and wide range operating temperature have drawn significant attention in recent years. However, monitoring the state of charge in supercapacitors in a cost-effective and flexible way is still challenging. Techniques such as transmission electron microscopy and X-ray diffraction can analyze the characteristics of supercapacitor well. But with large size and high price, they are not suitable for daily monitoring of the supercapacitors’ operation. In this paper, a low cost and easily fabricated fiber-optic localized surface plasmon resonance (LSPR) probe is proposed to monitor the state of charge of the electrode in a supercapacitor. The Au nanoparticles were loading on the fiber core as LSPR sensing region. In order to implant the fiber in the supercapacitor, a reflective type of fiber sensor was used. The results show that this tiny fiber-optic LSPR sensor can provide online monitoring of the state of charge during the charging and discharging process in situ. The intensity shift in LSPR sensor has a good linear relationship with the state of charge calculated by standard galvanostatic charging and discharging test. In addition, this LSPR sensor is insensitive to the temperature change, presenting a great potential in practical applications.

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Ran, Lingling, Yifei Tao, Kai Guo, Fei Shen, Hongping Zhou, Yongxuan Sun, Renbin Zhang, et al. "Bias-scanning based tunable LSPR sensor." Physical Chemistry Chemical Physics 20, no. 4 (2018): 2146–50. http://dx.doi.org/10.1039/c7cp07565k.

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The principle and the characteristics of the bias-scanning based tunable localized surface plasmon resonance (LSPR) sensors for environmental refractive index have been theoretically and numerically investigated in detail.

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Liu, Yun, Ning Zhang, Ping Li, Li Yu, Shimeng Chen, Yang Zhang, Zhenguo Jing, and Wei Peng. "Low-Cost Localized Surface Plasmon Resonance Biosensing Platform with a Response Enhancement for Protein Detection." Nanomaterials 9, no. 7 (July 16, 2019): 1019. http://dx.doi.org/10.3390/nano9071019.

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There are many potential applications for biosensors that can provide real-time analysis, such as environmental monitoring and disease prevention. In this study, we investigated a simple strategy for real-time protein detection, which had the advantages of affordability, fast response, portability, and ease of use. A robust quantification of protein interaction was achieved by combining capillary localized surface plasmon resonance (LSPR) sensors and complementary metal–oxide–semiconductor (CMOS) image sensors. Gold nanoparticles were modified on the inner wall of the capillary, which was used as a microfluidic channel and sensing surface. We functionalized one of the LSPR sensors using ligand bound to gold nanoparticle. Our proposed biosensing platform could be easily multiplexed to achieve high throughput screening of biomolecular interactions, and it has the potential for use in disposable sensors. Moreover, the sensing signal was enhanced by the extinction effect of gold nanoparticles. The experimental results showed that our device could achieve qualitative identification and quantitative measurement of transferrin and immunoglobulin G (IgG). As a field-portable and low-cost optical platform, the proposed LSPR biosensing device is broadly applicable to various protein binding tests via a similar self-assembly of organic ultrathin films.

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Rodrigues, Marco S., Joel Borges, Cláudia Lopes, Rui M. S. Pereira, Mikhail I. Vasilevskiy, and Filipe Vaz. "Gas Sensors Based on Localized Surface Plasmon Resonances: Synthesis of Oxide Films with Embedded Metal Nanoparticles, Theory and Simulation, and Sensitivity Enhancement Strategies." Applied Sciences 11, no. 12 (June 10, 2021): 5388. http://dx.doi.org/10.3390/app11125388.

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This work presents a comprehensive review on gas sensors based on localized surface plasmon resonance (LSPR) phenomenon, including the theory of LSPR, the synthesis of nanoparticle-embedded oxide thin films, and strategies to enhance the sensitivity of these optical sensors, supported by simulations of the electromagnetic properties. The LSPR phenomenon is known to be responsible for the unique colour effects observed in the ancient Roman Lycurgus Cup and at the windows of the medieval cathedrals. In both cases, the optical effects result from the interaction of the visible light (scattering and absorption) with the conduction band electrons of noble metal nanoparticles (gold, silver, and gold–silver alloys). These nanoparticles are dispersed in a dielectric matrix with a relatively high refractive index in order to push the resonance to the visible spectral range. At the same time, they have to be located at the surface to make LSPR sensitive to changes in the local dielectric environment, the property that is very attractive for sensing applications. Hence, an overview of gas sensors is presented, including electronic-nose systems, followed by a description of the surface plasmons that arise in noble metal thin films and nanoparticles. Afterwards, metal oxides are explored as robust and sensitive materials to host nanoparticles, followed by preparation methods of nanocomposite plasmonic thin films with sustainable techniques. Finally, several optical properties simulation methods are described, and the optical LSPR sensitivity of gold nanoparticles with different shapes, sensing volumes, and surroundings is calculated using the discrete dipole approximation method.

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Li, Jin, Haoru Wang, Zhi Li, Zhengcheng Su, and Yue Zhu. "Preparation and Application of Metal Nanoparticals Elaborated Fiber Sensors." Sensors 20, no. 18 (September 10, 2020): 5155. http://dx.doi.org/10.3390/s20185155.

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In recent years, surface plasmon resonance devices (SPR, or named plamonics) have attracted much more attention because of their great prospects in breaking through the optical diffraction limit and developing new photons and sensing devices. At the same time, the combination of SPR and optical fiber promotes the development of the compact micro-probes with high-performance and the integration of fiber and planar waveguide. Different from the long-range SPR of planar metal nano-films, the local-SPR (LSPR) effect can be excited by incident light on the surface of nano-scaled metal particles, resulting in local enhanced light field, i.e., optical hot spot. Metal nano-particles-modified optical fiber LSPR sensor has high sensitivity and compact structure, which can realize the real-time monitoring of physical parameters, environmental parameters (temperature, humidity), and biochemical molecules (pH value, gas-liquid concentration, protein molecules, viruses). In this paper, both fabrication and application of the metal nano-particles modified optical fiber LSPR sensor probe are reviewed, and its future development is predicted.

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Wang, Huafeng, Ting Fang, Hua Liu, Tianxiang Wei, and Zhihui Dai. "Gold Nanostar-Based Sensitive Catechol Plasmonic Colorimetric Sensing Platform with Ultra-Wide Detection Range." Chemosensors 10, no. 11 (October 25, 2022): 439. http://dx.doi.org/10.3390/chemosensors10110439.

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High sensitivity and a wide detection range are always the pursuit of sensor design. In this work, gold nanostars (Au NSs) featuring the shape of sea urchins with an absorption peak at the near infrared region (822 nm) were prepared. We proposed a Au NSs-based plasmonic colorimetric sensing platform for ultrasensitive catechol (CC) detection with a wide detection range from 3.33 nM to 107 μM and a limit of detection (LOD) at 1 nM. The target analyte, CC, was used to reduce silver ions (Ag+) to form silver (Ag) coating on the surface of Au NSs, which caused a blue-shift in the localized surface plasmon resonance (LSPR) of Au NSs. With the gradual increase in CC concentration, the Ag coating on the surface was gradually nucleated, and the LSPR blue-shift carried on. This strategy yields a wide LSPR shift by as much as 276 nm for plasmonic effects, enabling an ultra-wide range and the ultrasensitive detection of CC. This work will facilitate the research of target-mediated LSPR sensors and their wide application in environmental monitoring, food safety, and disease diagnosis.

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Qomaruddin, Olga Casals, Hutomo Suryo Wasisto, Andreas Waag, Joan Daniel Prades, and Cristian Fàbrega. "Visible-Light-Driven Room Temperature NO2 Gas Sensor Based on Localized Surface Plasmon Resonance: The Case of Gold Nanoparticle Decorated Zinc Oxide Nanorods (ZnO NRs)." Chemosensors 10, no. 1 (January 11, 2022): 28. http://dx.doi.org/10.3390/chemosensors10010028.

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In this work, nitrogen dioxide (NO2) gas sensors based on zinc oxide nanorods (ZnO NRs) decorated with gold nanoparticles (Au NPs) working under visible-light illumination with different wavelengths at room temperature are presented. The contribution of localized surface plasmon resonant (LSPR) by Au NPs attached to the ZnO NRs is demonstrated. According to our results, the presence of LSPR not only extends the functionality of ZnO NRs towards longer wavelengths (green light) but also increases the response at shorter wavelengths (blue light) by providing new inter-band gap energetic states. Finally, the sensing mechanism based on LSPR Au NPs is proposed.

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Badi'ah, Hanim Istatik, Dinda Khoirul Ummah, Ni Nyoman Tri Puspaningsih, and Ganden Supriyanto. "Strategies in Improving Sensitivity of Colorimetry Sensor Based on Silver Nanoparticles in Chemical and Biological Samples." Indonesian Journal of Chemistry 22, no. 6 (July 27, 2022): 1705. http://dx.doi.org/10.22146/ijc.73194.

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Colorimetric sensors-based silver nanoparticles (AgNPs) are very interesting to be studied and developed because of the simplicity and ease in the principle of detection. It does not require sophisticated and affordable tools but still has high sensitivity. The coefficient extinction of AgNPs is relatively higher than AuNPs of the same size, making the sensitivity of AgNPs higher than AuNPs. The principle of detection is based on the aggregation of nanoparticles with analytes that causes shifting in Localized Surface Plasmon Resonance (LSPR) to a larger wavelength, commonly called a bathochromic shift or redshift. It is a favorite phenomenon because it is more easily observed with naked eyes. This sensor shows a good analytic performance with high sensitivity due to strong LSPR and good strategies that selectively bring interaction between analytes and AgNPs. AgNPs are characterized using UV-Visible (Ultra Violet-Visible), TEM (Transmission Electron Microscope), FTIR (Fourier Transform Infrared), and DLS (Dynamic Light Scattering), and many analytes have been detected with this sensor successfully. This article discusses several important parameters in increasing the sensitivity of AgNPs colorimetric sensors. Finally, it can be used as guidelines in the development of methods in the future.

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Wu, Fan, Lin Cheng, and Wenhui Wang. "Surface Plasmon Resonance of Large-Size Ag Nanobars." Micromachines 13, no. 4 (April 18, 2022): 638. http://dx.doi.org/10.3390/mi13040638.

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Silver nanobars have attracted much attention due to their distinctive localized surface plasmon resonance (LSPR) in the visible and near-infrared regions. In this work, large-size Ag nanobars (length: 400~1360 nm) working at a longer-wavelength near-infrared range (>1000 nm) have been synthesized. By using the finite-difference time-domain (FDTD) simulation, the LSPR properties of a single large-size Ag nanobar are systematically investigated. The LSPR in Ag nanobar can be flexibly tuned in a wide wavelength range (400~2000 nm) by changing the bar length or etching the bar in the length direction. Our work provides a flexible way to fabricate nanoparticle arrays using large-size nanobars and throws light on the applications of large-size nanomaterials on wide spectral absorbers, LSPR-based sensors and nanofilters.

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Santos, Paulo, José Almeida, and Luis Coelho. "Study of LSPR Spectral Analysis Techniques on SPR Optical Fiber Sensors." U.Porto Journal of Engineering 8, no. 3 (May 30, 2022): 12–17. http://dx.doi.org/10.24840/2183-6493_008.003_0004.

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Nanoparticles create localized surface plasmonic resonances (LSPR) with lower surrounding refractive index (SRI) sensitivities than their propagating SPR counterpart, originated in thin films. Historically, LSPR SRI sensitivities enhancements were achieved through spectral analysis methods that focus on unique spectral features. Herein, a study using that methodology was applied on SPR devices resulting in an increased sensitivity to SRI. It was found that by applying the inflection point method on optical fiber SPR sensors resulted in both sensitivity and resolution increments up to 44 and 35 %, respectively, in the SRI range from 1.3333 to 1.4150. Thus, successfully improving sensing capabilities of SPR based optical fiber sensors.

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Jiang, Jing, Xinhao Wang, Shuang Li, Fei Ding, Nantao Li, Shaoyu Meng, Ruifan Li, Jia Qi, Qingjun Liu, and Gang Logan Liu. "Plasmonic nano-arrays for ultrasensitive bio-sensing." Nanophotonics 7, no. 9 (August 28, 2018): 1517–31. http://dx.doi.org/10.1515/nanoph-2018-0023.

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AbstractSurface plasmon resonance (SPR) and localized SPR (LSPR) effects have been shown as the principles of some highlysensitive sensors in recent decades. Due to the advances in nano-fabrication technology, the plasmon nano-array sensors based on SPR and LSPR phenomena have been widely used in chemical and bioloical analysis. Sensing with surface-enhanced field and sensing for refractive index changes are able to identify the analytes quantitatively and qualitatively. With the newly developed ultrasensitive plasmonic biosensors, platforms with excellent performance have been built for various biomedical applications, including point-of-care diagnosis and personalized medicine. In addition, flexible integration of plasmonics nano-arrays and combining them with electrochemical sensing have significantly enlarged the application scenarios of the plasmonic nano-array sensors, as well as improved the sensing accuracy.

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Kim, Dong Min, Jong Seong Park, Seung-Woon Jung, Jinho Yeom, and Seung Min Yoo. "Biosensing Applications Using Nanostructure-Based Localized Surface Plasmon Resonance Sensors." Sensors 21, no. 9 (May 4, 2021): 3191. http://dx.doi.org/10.3390/s21093191.

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Localized surface plasmon resonance (LSPR)-based biosensors have recently garnered increasing attention due to their potential to allow label-free, portable, low-cost, and real-time monitoring of diverse analytes. Recent developments in this technology have focused on biochemical markers in clinical and environmental settings coupled with advances in nanostructure technology. Therefore, this review focuses on the recent advances in LSPR-based biosensor technology for the detection of diverse chemicals and biomolecules. Moreover, we also provide recent examples of sensing strategies based on diverse nanostructure platforms, in addition to their advantages and limitations. Finally, this review discusses potential strategies for the development of biosensors with enhanced sensing performance.

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Bousiakou, Leda G., Hrvoje Gebavi, Lara Mikac, Stefanos Karapetis, and Mile Ivanda. "Surface Enhanced Raman Spectroscopy for Molecular Identification- a Review on Surface Plasmon Resonance (SPR) and Localised Surface Plasmon Resonance (LSPR) in Optical Nanobiosensing." Croatica chemica acta 92, no. 4 (2019): 479–94. http://dx.doi.org/10.5562/cca3558.

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Surface plasmon resonance (SPR) allows for real-time, label-free optical detection of many chemical and biological substances. Having emerged in the last two decades, it is a widely used technique due to its non-invasive nature, allowing for the ultra-sensitive detection of a number of analytes. This review article discusses the principles, providing examples and illustrating the utility of SPR within the frame of plasmonic nanobiosensing, while making comparisons with its successor, namely localized surface plasmon resonance (LSPR). In particular LSPR utilizes both metal nanoparticle arrays and single nanoparticles, as compared to a continuous film of gold as used in traditional SPR. LSPR, utilizes metal nanoparticle arrays or single nanoparticles that have smaller sizes than the wavelength of the incident light, measuring small changes in the wavelength of the absorbance position, rather than the angle as in SPR. We introduce LSPR nanobiosensing by describing the initial experiments performed, shift-enhancement methods, exploitation of the short electromagnetic ﬁeld decay length, and single nanoparticle sensors are as pathways to further exploit the strengths of LSPR nanobiosensing. Coupling molecular identiﬁcation to LSPR spectroscopy is also explored and thus examples from surface-enhanced Raman spectroscopy are provided. The unique characteristics of LSPR nanobiosensing are emphasized and the challenges using LSPR nanobiosensors for detection of biomolecules as a biomarker are discussed.

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Rao, Honghong, Xin Xue, Hongqiang Wang, and Zhonghua Xue. "Gold nanorod etching-based multicolorimetric sensors: strategies and applications." Journal of Materials Chemistry C 7, no. 16 (2019): 4610–21. http://dx.doi.org/10.1039/c9tc00757a.

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Gold nanorod (AuNR) colorimetric sensors have emerged as powerful tools in various chemosensing and biosensing applications due to their localized surface plasmon resonance (LSPR) extinction in the visible range.

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Liu, Ju, and Zhiyuan Li. "Control of Surface Plasmon Resonance in Silver Nanocubes by CEP-Locked Laser Pulse." Photonics 9, no. 2 (January 19, 2022): 53. http://dx.doi.org/10.3390/photonics9020053.

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Localized surface plasmon resonance (LSPR) of metal nanoparticles has attracted increasing attention in surface-enhanced Raman scattering, chemical and biological sensing applications. In this article, we calculate the optical extinction spectra of a silver nanocube driven by an ultrashort carrier envelope phase (CEP)-locked laser pulse. Five LSPR modes are clearly excited in the optical spectra. We analyze the physical origin of each mode from the charge distribution on different parts of the cubic particle and the dipole and quadrupole excitation features at the LSPR peaks. The charge distribution follows a simple rule that when the charge concentrates from the face to the corners of the cubic particle, the resonant wavelength red-shifts. Then we modulate the LSPR spectra by changing CEP. The results show that CEP has selective plasmon mode excitation functionality and can act as a novel modulation role on LSPR modes. Our work suggests a novel means to regulate LSPR modes and the corresponding optical properties of metal nanoparticles via various freedoms of controlled optical field, which can be useful for optimized applications in chemical and biological sensors, single molecule detection, and so on.

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Nan, Minghui, Bobby Aditya Darmawan, Gwangjun Go, Shirong Zheng, Junhyeok Lee, Seokjae Kim, Taeksu Lee, Eunpyo Choi, Jong-Oh Park, and Doyeon Bang. "Wearable Localized Surface Plasmon Resonance-Based Biosensor with Highly Sensitive and Direct Detection of Cortisol in Human Sweat." Biosensors 13, no. 2 (January 24, 2023): 184. http://dx.doi.org/10.3390/bios13020184.

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Wearable biosensors have the potential for developing individualized health evaluation and detection systems owing to their ability to provide continuous real-time physiological data. Among various wearable biosensors, localized surface plasmon resonance (LSPR)-based wearable sensors can be versatile in various practical applications owing to their sensitive interactions with specific analytes. Understanding and analyzing endocrine responses to stress is particularly crucial for evaluating human performance, diagnosing stress-related diseases, and monitoring mental health, as stress takes a serious toll on physiological health and psychological well-being. Cortisol is an essential biomarker of stress because of the close relationship between cortisol concentration in the human body and stress level. In this study, a flexible LSPR biosensor was manufactured to detect cortisol levels in the human body by depositing gold nanoparticle (AuNP) layers on a 3-aminopropyltriethoxysilane (APTES)-functionalized poly (dimethylsiloxane) (PDMS) substrate. Subsequently, an aptamer was immobilized on the surface of the LSPR substrate, enabling highly sensitive and selective cortisol capture owing to its specific cortisol recognition. The biosensor exhibited excellent detection ability in cortisol solutions of various concentrations ranging from 0.1 to 1000 nM with a detection limit of 0.1 nM. The flexible LSPR biosensor also demonstrated good stability under various mechanical deformations. Furthermore, the cortisol levels of the flexible LSPR biosensor were also measured in the human epidermis before and after exercise as well as in the morning and afternoon. Our biosensors, which combine easily manufactured flexible sensors with sensitive cortisol-detecting molecules to measure human stress levels, could be versatile candidates for human-friendly products.

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Manzo, Maurizio, Omar Cavazos, Zhenhua Huang, and Liping Cai. "Plasmonic and Hybrid Whispering Gallery Mode–Based Biosensors: Literature Review." JMIR Biomedical Engineering 6, no. 2 (April 12, 2021): e17781. http://dx.doi.org/10.2196/17781.

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Background The term “plasmonic” describes the relationship between electromagnetic fields and metallic nanostructures. Plasmon-based sensors have been used innovatively to accomplish different biomedical tasks, including detection of cancer. Plasmonic sensors also have been used in biochip applications and biosensors and have the potential to be implemented as implantable point-of-care devices. Many devices and methods discussed in the literature are based on surface plasmon resonance (SPR) and localized SPR (LSPR). However, the mathematical background can be overwhelming for researchers at times. Objective This review article discusses the theory of SPR, simplifying the underlying physics and bypassing many equations of SPR and LSPR. Moreover, we introduce and discuss the hybrid whispering gallery mode (WGM) sensing theory and its applications. Methods A literature search in ScienceDirect was performed using keywords such as “surface plasmon resonance,” “localized plasmon resonance,” and “whispering gallery mode/plasmonic.” The search results retrieved many articles, among which we selected only those that presented a simple explanation of the SPR phenomena with prominent biomedical examples. Results SPR, LSPR, tilted fiber Bragg grating, and hybrid WGM phenomena were explained and examples on biosensing applications were provided. Conclusions This minireview presents an overview of biosensor applications in the field of biomedicine and is intended for researchers interested in starting to work in this field. The review presents the fundamental notions of plasmonic sensors and hybrid WGM sensors, thereby allowing one to get familiar with the terminology and underlying complex formulations of linear and nonlinear optics.

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Tu, M. H., T. Sun, and K. T. V. Grattan. "LSPR optical fibre sensors based on hollow gold nanostructures." Sensors and Actuators B: Chemical 191 (February 2014): 37–44. http://dx.doi.org/10.1016/j.snb.2013.09.094.

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Kaminska, I., T. Maurer, R. Nicolas, M. Renault, T. Lerond, R. Salas-Montiel, Z. Herro, et al. "Near-Field and Far-Field Sensitivities of LSPR Sensors." Journal of Physical Chemistry C 119, no. 17 (April 22, 2015): 9470–76. http://dx.doi.org/10.1021/acs.jpcc.5b00566.

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Yang, Wen, Jing Yu, Xiangtai Xi, Yang Sun, Yiming Shen, Weiwei Yue, Chao Zhang, and Shouzhen Jiang. "Preparation of Graphene/ITO Nanorod Metamaterial/U-Bent-Annealing Fiber Sensor and DNA Biomolecule Detection." Nanomaterials 9, no. 8 (August 12, 2019): 1154. http://dx.doi.org/10.3390/nano9081154.

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In this paper, a graphene/ITO nanorod metamaterial/U-bent-annealing (Gr/ITO-NM/U-bent-A)-based U-bent optical fiber local surface plasmon resonance (LSPR) sensor is presented and demonstrated for DNA detection. The proposed sensor, compared with other conventional sensors, exhibits higher sensitivity, lower cost, as well as better biological affinity and oxidize resistance. Besides, it has a structure of an original Indium Tin Oxides (ITO) nanocolumn array coated with graphene, allowing the sensor to exert significant bulk plasmon resonance effect. Moreover, for its discontinuous structure, a larger specific surface area is created to accommodate more biomolecules, thus maximizing the biological properties. The fabricated sensors exhibit great performance (690.7 nm/RIU) in alcohol solution testing. Furthermore, it also exhibits an excellent linear response (R2 = 0.998) to the target DNA with respective concentrations from 0.1 to 100 nM suggesting the promising medical applications of such sensors.

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Figueiredo, Nuno M., Ricardo Serra, and Albano Cavaleiro. "Robust LSPR Sensing Using Thermally Embedded Au Nanoparticles in Glass Substrates." Nanomaterials 11, no. 6 (June 17, 2021): 1592. http://dx.doi.org/10.3390/nano11061592.

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The poor adhesion and chemical and thermal stability of plasmonic nanostructures deposited on solid surfaces are a hindrance to the longevity and long-term development of robust localized surface plasmon resonance (LSPR)-based systems. In this paper, we have deposited gold (Au) nanolayers with thicknesses above the percolation limit over glass substrates and have used a thermal annealing treatment at a temperature above the substrate’s glass transition temperature to promote the dewetting, recrystallization, and thermal embedding of Au nanoparticles (NPs). Due to the partial embedding in glass, the NPs were strongly adherent to the surface of the substrate and were able to resist to the commonly used cleaning procedures and mechanical adhesion tests alike. The reflectivity of the embedded nanostructures was studied and shown to be strongly dependent on the NP size/shape distributions and on the degree of NP embedding. Strong optical scattering bands with increasing width and redshifted LSPR peak position were observed with the Au content. Refractive index sensitivity (RIS) values between 150 and 360 nm/RIU (concerning LSPR band edge shift) or between 32 and 72 nm/RIU (concerning LSPR peak position shift) were obtained for the samples having narrower LSPR extinction bands. These robust LSPR sensors can be used following a simple excitation/detection scheme consisting of a reflectance measurement at a fixed angle and wavelength.

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Bansal, Amit, and S. S. Verma. "Searching for Alternative Plasmonic Materials for Specific Applications." Indian Journal of Materials Science 2014 (May 12, 2014): 1–10. http://dx.doi.org/10.1155/2014/897125.

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The localized surface plasmon resonance (LSPR) based optical properties such as light scattering, absorption, and extinction efficiencies of multimetallic and metal-semiconductor nanostructures will be studied. The effect of size, surrounding medium, interaction between the particles, composition of the particles, and substrate on LSPR peak position, its line width, and maxima of cross-sections will also be discussed to optimize the selected systems for various applications like plasmonic sensors and biomedical applications and to enhance the efficiency of solar cells. Therefore, by varying all these factors, the LSPR peak of multimetallic and metal-semiconductor nanostructures can be tuned over the entire UV-visible to infrared (IR) region of the electromagnetic spectrum. Moreover the optical properties of underlying semiconductor materials can be enhanced by combining the semiconductor with noble metal nanoparticles.

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Oh, Seungju, Hyeyeon Hur, Yoonjae Kim, Seongcheol Shin, Hyunjeong Woo, Jonghoon Choi, and Hyun Ho Lee. "Peptide Specific Nanoplastic Detection Based on Sandwich Typed Localized Surface Plasmon Resonance." Nanomaterials 11, no. 11 (October 28, 2021): 2887. http://dx.doi.org/10.3390/nano11112887.

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Recently, various waste microplastics sensors have been introduced in response to environmental and biological hazards posed by waste microplastics. In particular, the detrimental effects of nano-sized plastics or nanoplastics have been reported to be severe. Moreover, there have been many difficulties for sensing microplastics due to the limited methodologies for selectively recognizing nanoplastics. In this study, a customized gold nanoparticles (Au NPs) based localized surface plasmon resonance (LSPR) system having bio-mimicked peptide probes toward the nanoplastics was demonstrated. The specific determination through the oligo-peptide recognition was accomplished by chemical conjugation both on the LSPR chip’s 40~50 nm Au NPs and sandwiched 5 nm Au NPs, respectively. The peptide probe could selectively bind to polystyrene (PS) nanoplastics in the forms of fragmented debris by cryo-grinding. A simple UV-Vis spectrophotometer was used to identify the LSPR sensing by primarily measuring the absorbance change and shift of absorption peak. The sandwich-binding could increase the LSPR detection sensitivity up to 60% due to consecutive plasmonic effects. In addition, microwave-boiled DI water inside of a styrofoam container was tested for putative PS nanoplastics resource as a real accessible sample. The LSPR system could be a novel protocol overcoming the limitations from conventional nanoplastic detection.

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Qi, Miao, Nancy Meng Ying Zhang, Kaiwei Li, Swee Chuan Tjin, and Lei Wei. "Hybrid Plasmonic Fiber-Optic Sensors." Sensors 20, no. 11 (June 8, 2020): 3266. http://dx.doi.org/10.3390/s20113266.

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With the increasing demand of achieving comprehensive perception in every aspect of life, optical fibers have shown great potential in various applications due to their highly-sensitive, highly-integrated, flexible and real-time sensing capabilities. Among various sensing mechanisms, plasmonics based fiber-optic sensors provide remarkable sensitivity benefiting from their outstanding plasmon–matter interaction. Therefore, surface plasmon resonance (SPR) and localized SPR (LSPR)-based hybrid fiber-optic sensors have captured intensive research attention. Conventionally, SPR- or LSPR-based hybrid fiber-optic sensors rely on the resonant electron oscillations of thin metallic films or metallic nanoparticles functionalized on fiber surfaces. Coupled with the new advances in functional nanomaterials as well as fiber structure design and fabrication in recent years, new solutions continue to emerge to further improve the fiber-optic plasmonic sensors’ performances in terms of sensitivity, specificity and biocompatibility. For instance, 2D materials like graphene can enhance the surface plasmon intensity at the metallic film surface due to the plasmon–matter interaction. Two-dimensional (2D) morphology of transition metal oxides can be doped with abundant free electrons to facilitate intrinsic plasmonics in visible or near-infrared frequencies, realizing exceptional field confinement and high sensitivity detection of analyte molecules. Gold nanoparticles capped with macrocyclic supramolecules show excellent selectivity to target biomolecules and ultralow limits of detection. Moreover, specially designed microstructured optical fibers are able to achieve high birefringence that can suppress the output inaccuracy induced by polarization crosstalk and meanwhile deliver promising sensitivity. This review aims to reveal and explore the frontiers of such hybrid plasmonic fiber-optic platforms in various sensing applications.

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Uchida, Shuhei, Kazuya Yamamura, and Nobuyuki Zettsu. "Fabrication of Precise Asymmetric Nanoshells Array with Nanogaps for a Label-Free Immunoassay Based on NIR-Light Responsive LSPR." Key Engineering Materials 523-524 (November 2012): 680–85. http://dx.doi.org/10.4028/www.scientific.net/kem.523-524.680.

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Localized surface plasmon resonance (LSPR) based sensors are a well established technology utilized for label-free biochemical sensing in immunoassay, medical diagnostics and environmental monitoring. The understanding of asymmetric metal nanoparticles, new object for complex, coupled plasmon systems providing localized significantly enhanced E-field, is central to a wide range of novel applications and processes in science of higher sensitive sensing systems. However, few methods are available for actual characterization of such nanostructures at the single particle level. Here we propose a precise and large sized scale fabrication technique for asymmetric nanoshells array with nanogaps of several tens of nanometers for LSPR sensor through atmospheric pressure plasma etching processes. A nanoshell was simply constructed by laminating thin Au films on periodic isolated polymer nanoparticles template. This nanoshells array was expected to exhibit specific near-infrared plasmonic properties. When measuring the sensitivity, nanoshells array exhibited a high sensitivity to changes of surrounding refractive index and showed a higher sensor figure of merit than the alternative structures. This indicated that the enhanced plasmon E-field in the asymmetric nanostructures improved sensor performance. Our fabrication technique and the optical properties of the arrays will provide useful information for developing new plasmonic applications.

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Gowri, A., and V. V. R. Sai. "Development of LSPR based U-bent plastic optical fiber sensors." Sensors and Actuators B: Chemical 230 (July 2016): 536–43. http://dx.doi.org/10.1016/j.snb.2016.02.074.

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Wang, Jun, Gang Wang, Changlong Liu, Yimo Wang, and Hui Qian. "Metal ion implantation into transparent dielectric slab: an effective route to high-stability localized surface plasmon resonance sensors." Nanotechnology 33, no. 3 (October 29, 2021): 035711. http://dx.doi.org/10.1088/1361-6528/ac2f23.

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Abstract Ag/SiO2 and Au/SiO2 samples were prepared by separately implanting 30 keV Ag and Au ions into 0.5-mm-thick SiO2 slabs at a fluence of 6 × 1016 ion·cm−2, and their optical and structural properties were studied in detail by using a fiber spectrometer and a transmission electron microscope, respectively. Our results showed that the two samples featured by their respective nanocomposite surface layers were asymmetrical in structure, and hence, their characteristic signals in the reflectance spectra excited by the lights incident from the rear surfaces were able to exhibit corresponding blueshifts when the overlays on the implanted surfaces were increased in refractive index with respect to air. Our results also showed that each of characteristic signals was strongly dependent on the localized surface plasmon resonance (LSPR) behavior of the involved Ag or Au nanoparticles (NPs), and it could not appear at a wavelength position smaller than or equal to that of the LSPR absorption peak since the involved Ag or Au NPs were quite small in size. These results meant that the two samples could be regarded as the LSPR sensors with a negative refractive index sensitivity (RIS), although their sensing abilities would lose when the overlays were very large in refractive index. Especially, the two samples were demonstrated to be relatively high in stability because the involved Ag and Au NPs were closely hugged and chemically protected by the matrices of SiO2, and consequently, they could have a chance to become prospective sensing devices in some special fields as long as their RISs and linearities could be improved in the future. The above findings substantially confirmed that the metal ion implantation into transparent dielectric slab was an effective route to the high-stability LSPR sensors.

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Bhalla, Nikhil, Aditya Jain, Yoonjoo Lee, Amy Q. Shen, and Doojin Lee. "Dewetting Metal Nanofilms—Effect of Substrate on Refractive Index Sensitivity of Nanoplasmonic Gold." Nanomaterials 9, no. 11 (October 27, 2019): 1530. http://dx.doi.org/10.3390/nano9111530.

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The localized surface plasmon resonance (LSPR) sensitivity of metal nanostructures is strongly dependent on the interaction between the supporting substrate and the metal nanostructure, which may cause a change in the local refractive index of the metal nanostructure. Among various techniques used for the development of LSPR chip preparation, solid-state dewetting of nanofilms offers fast and cost effective methods to fabricate large areas of nanostructures on a given substrate. Most of the previous studies have focused on the effect of the size, shape, and inter-particle distance of the metal nanostructures on the LSPR sensitivity. In this work, we reveal that the silicon-based supporting substrate influences the LSPR associated refractive index sensitivity of gold (Au) nanostructures designed for sensing applications. Specifically, we develop Au nanostructures on four different silicon-based ceramic substrates (Si, SiO2, Si3N4, SiC) by thermal dewetting process and demonstrate that the dielectric properties of these ceramic substrates play a key role in the LSPR-based refractive index (RI) sensitivity of the Au nanostructures. Among these Si-supported Au plasmonic refractive index (RI) sensors, the Au nanostructures on the SiC substrates display the highest average RI sensitivity of 247.80 nm/RIU, for hemispherical Au nanostructures of similar shapes and sizes. Apart from the significance of this work towards RI sensing applications, our results can be advantageous for a wide range of applications where sensitive plasmonic substrates need to be incorporated in silicon based optoelectronic devices.

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Zheng, Yuqiao, Sumin Bian, Jiacheng Sun, Liaoyong Wen, Guoguang Rong, and Mohamad Sawan. "Label-Free LSPR-Vertical Microcavity Biosensor for On-Site SARS-CoV-2 Detection." Biosensors 12, no. 3 (February 28, 2022): 151. http://dx.doi.org/10.3390/bios12030151.

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Cost-effective, rapid, and sensitive detection of SARS-CoV-2, in high-throughput, is crucial in controlling the COVID-19 epidemic. In this study, we proposed a vertical microcavity and localized surface plasmon resonance hybrid biosensor for SARS-CoV-2 detection in artificial saliva and assessed its efficacy. The proposed biosensor monitors the valley shifts in the reflectance spectrum, as induced by changes in the refractive index within the proximity of the sensor surface. A low-cost and fast method was developed to form nanoporous gold (NPG) with different surface morphologies on the vertical microcavity wafer, followed by immobilization with the SARS-CoV-2 antibody for capturing the virus. Modeling and simulation were conducted to optimize the microcavity structure and the NPG parameters. Simulation results revealed that NPG-deposited sensors performed better in resonance quality and in sensitivity compared to gold-deposited and pure microcavity sensors. The experiment confirmed the effect of NPG surface morphology on the biosensor sensitivity as demonstrated by simulation. Pre-clinical validation revealed that 40% porosity led to the highest sensitivity for SARS-CoV-2 pseudovirus at 319 copies/mL in artificial saliva. The proposed automatic biosensing system delivered the results of 100 samples within 30 min, demonstrating its potential for on-site coronavirus detection with sufficient sensitivity.

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Goicoechea, Rivero, Sada, and Arregui. "Self-Referenced Optical Fiber Sensor for Hydrogen Peroxide Detection based on LSPR of Metallic Nanoparticles in Layer-by-Layer Films." Sensors 19, no. 18 (September 7, 2019): 3872. http://dx.doi.org/10.3390/s19183872.

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Intensity-based optical fiber sensors are one of the most studied sensor approaches thanks to their simplicity and low cost. Nevertheless, their main issue is their lack of robustness since any light source fluctuation, or unexpected optical setup variation is directly transferred to the output signal, which, significantly reduces their reliability. In this work, a simple and robust hydrogen peroxide (H2O2) optical fiber sensor is proposed based on the Localized Surface Plasmon Resonance (LSPR) sensitivity of silver and gold metallic nanoparticles. The precise and robust detection of H2O2 concentrations in the ppm range is very interesting for the scientific community, as it is a pathological precursor in a wide variety of damage mechanisms where its presence can be used to diagnose important diseases such as Parkinson’s disease, diabetes, asthma, or even Alzheimer’s disease). In this work, the sensing principle is based the oxidation of the silver nanoparticles due the action of the hydrogen peroxide, and consequently the reduction of the efficiency of the plasmonic coupling. At the same time, gold nanoparticles show a high chemical stability, and therefore provide a stable LSPR absorption band. This provides a stable real-time reference that can be extracted from the spectral response of the optical fiber sensor, giving a reliable reading of the hydrogen peroxide concentration.

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Rodrigues, Marco S., Joel Borges, and Filipe Vaz. "Enhancing the Sensitivity of Nanoplasmonic Thin Films for Ethanol Vapor Detection." Materials 13, no. 4 (February 14, 2020): 870. http://dx.doi.org/10.3390/ma13040870.

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Nanoplasmonic thin films, composed of noble metal nanoparticles (gold) embedded in an oxide matrix, have been a subject of considerable interest for Localized Surface Plasmon Resonance (LSPR) sensing. Ethanol is one of the promising materials for fuel cells, and there is an urgent need of a new generation of safe optical sensors for its detection. In this work, we propose the development of sensitive plasmonic platforms to detect molecular analytes (ethanol) through changes of the LSPR band. The thin films were deposited by sputtering followed by a heat treatment to promote the growth of the gold nanoparticles. To enhance the sensitivity of the thin films and the signal-to-noise ratio (SNR) of the transmittance–LSPR sensing system, physical plasma etching was used, resulting in a six-fold increase of the exposed gold nanoparticle area. The transmittance signal at the LSPR peak position increased nine-fold after plasma treatment, and the quality of the signal increased six times (SNR up to 16.5). The optimized thin films seem to be promising candidates to be used for ethanol vapor detection. This conclusion is based not only on the current sensitivity response but also on its enhancement resulting from the optimization routines of thin films’ architectures, which are still under investigation.

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Chauhan, Maya, and Vinod Kumar Singh. "Review on recent experimental SPR/LSPR based fiber optic analyte sensors." Optical Fiber Technology 64 (July 2021): 102580. http://dx.doi.org/10.1016/j.yofte.2021.102580.

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Fantoni, Alessandro, Vladan Stojkovic, Ana Carvalho, Ana P. C. Ribeiro, and Elisabete C. B. A. Alegria. "Characterization of AuNPs+rGO as a functionalized layer for LSPR sensors." Materials Letters: X 5 (March 2020): 100032. http://dx.doi.org/10.1016/j.mlblux.2019.100032.

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Susu, Laurentiu, Andreea Campu, Ana Craciun, Adriana Vulpoi, Simion Astilean, and Monica Focsan. "Designing Efficient Low-Cost Paper-Based Sensing Plasmonic Nanoplatforms." Sensors 18, no. 9 (September 11, 2018): 3035. http://dx.doi.org/10.3390/s18093035.

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Paper-based platforms can be a promising choice as portable sensors due to their low-cost and facile fabrication, ease of use, high sensitivity, specificity and flexibility. By combining the qualities of these 3D platforms with the optical properties of gold nanoparticles, it is possible to create efficient nanodevices with desired biosensing functionalities. In this work, we propose a new plasmonic paper-based dual localized surface plasmon resonance–surface-enhanced Raman scattering (LSPR-SERS) nanoplatform with improved detection abilities in terms of high sensitivity, uniformity and reproducibility. Specifically, colloidal gold nanorods (GNRs) with a well-controlled plasmonic response were firstly synthesized and validated as efficient dual LSPR-SERS nanosensors in solution using the p-aminothiophenol (p-ATP) analyte. GNRs were then efficiently immobilized onto the paper via the immersion approach, thus obtaining plasmonic nanoplatforms with a modulated LSPR response. The successful deposition of the nanoparticles onto the cellulose fibers was confirmed by LSPR measurements, which demonstrate the preserved plasmonic response after immobilization, as well as by dark-field microscopy and scanning electron microscopy investigations, which confirm their uniform distribution. Finally, a limit of detection for p-ATP as low as 10−12 M has been achieved by our developed SERS-based paper nanoplatform, proving that our optimized plasmonic paper-based biosensing design could be further considered as an excellent candidate for miniaturized biomedical applications.

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Morsin, Marlia, Muhamad Mat Salleh, Akrajas Ali Umar, and Muhammad Yahaya. "Localized Surface Plasmon Resonance Sensor of Gold Nanoplates for Detection of Boric Acid." Key Engineering Materials 605 (April 2014): 356–59. http://dx.doi.org/10.4028/www.scientific.net/kem.605.356.

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Localized surface plasmon resonance (LSPR) peak wavelength of nanostructures metallic materials, such as gold and silver, is very sensitive to the dielectric environment of the materials; hence widely used as sensors to detect various types of chemicals. In this study, high - yield gold nanoplates ca. 63% have been grown on the quartz substrate using the seed - mediated growth method. The grown gold nanoplates exhibit variety of shapes such as triangular, hexagonal, truncated hexagonal and flat rod. The LSPR spectrum of Au nanoplates sample has two absorption bands; centring at 543 nm and 710 nm, which are associated with transverse SPR (t-SPR) and longitudinal SPR (l-SPR) respectively. The intensities and peaks position of these two bands were found to linearly change with the concentration of boric acid solutions.

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Rodrigues, Marco S., Joel Borges, and Filipe Vaz. "Plasmonic Strain Sensors Based on Au-TiO2 Thin Films on Flexible Substrates." Sensors 22, no. 4 (February 11, 2022): 1375. http://dx.doi.org/10.3390/s22041375.

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This study aimed at introducing thin films exhibiting the localized surface plasmon resonance (LSPR) phenomenon with a reversible optical response to repeated uniaxial strain. The sensing platform was prepared by growing gold (Au) nanoparticles throughout a titanium dioxide dielectric matrix. The thin films were deposited on transparent polymeric substrates, using reactive magnetron sputtering, followed by a low temperature thermal treatment to grow the nanoparticles. The microstructural characterization of the thin films’ surface revealed Au nanoparticle with an average size of 15.9 nm, an aspect ratio of 1.29 and an average nearest neighbor nanoparticle at 16.3 nm distance. The plasmonic response of the flexible nanoplasmonic transducers was characterized with custom-made mechanical testing equipment using simultaneous optical transmittance measurements. The higher sensitivity that was obtained at a maximum strain of 6.7%, reached the values of 420 nm/ε and 110 pp/ε when measured at the wavelength or transmittance coordinates of the transmittance-LSPR band minimum, respectively. The higher transmittance gauge factor of 4.5 was obtained for a strain of 10.1%. Optical modelling, using discrete dipole approximation, seems to correlate the optical response of the strained thin film sensor to a reduction in the refractive index of the matrix surrounding the gold nanoparticles when uniaxial strain is applied.

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Jia, Shuo, Aiwen Ma, Hanpeng Dong, and Shanhong Xia. "Quantifiable Effect of Interparticle Plasmonic Coupling on Sensitivity and Tuning Range for Wavelength-Mode LSPR Fiber Sensor Fabricated by Simple Immobilization Method." Sensors 22, no. 23 (November 23, 2022): 9075. http://dx.doi.org/10.3390/s22239075.

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Herein a gold nanosphere (AuNS)-coated wavelength-mode localized surface plasmon resonance (LSPR) fiber sensor was fabricated by a simple and time-saving electrostatic self-assembly method using poly(allylamine hydrochloride). Based on the localized enhanced coupling effect between AuNSs, the LSPR spectrums of the AuNS monolayer with good dispersity and high density exhibited a favourable capability for refractive index (RI) measurement. Based on the results obtained from the optimization for AuNS distribution, sensing length, and RI range, the best RI sensitivity of the fiber modified by 100 nm AuNS reached up to about 2975 nm/RIU, with the surrounding RI range from 1.3322 to 1.3664. Using an 80 nm AuNS-modified fiber sensor, the RI sensitivity of 3953 nm/RIU was achieved, with the RI range increased from 1.3744 to 1.3911. The effect of sensing length to RI sensitivity was proven to be negligible. Furthermore, the linear relationship between the RI sensitivity and plasma resonance frequency of the bulk metal, which was dependent on the interparticle plasmon coupling effect, was quantified. Additionally, the resonance peak was tuned from 539.18 nm to 820.48 nm by different sizes of AuNSs-coated fiber sensors at a RI of 1.3322, which means the spectrum was extended from VIS to NIR. It has enormous potential in hypersensitive biochemistry detection at VIS and NIR ranges.

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Roldán, M. V., N. S. Pellegri, and O. A. de Sanctis. "Optical Response of Silver Nanoparticles Stabilized by Amines to LSPR based Sensors." Procedia Materials Science 1 (2012): 594–600. http://dx.doi.org/10.1016/j.mspro.2012.06.080.

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Liu, Jianpeng, Yaqi Ma, Jinhai Shao, Sichao Zhang, and Yifang Chen. "Ultra-tall sub-wavelength gold nano pillars for high sensitive LSPR sensors." Microelectronic Engineering 196 (September 2018): 7–12. http://dx.doi.org/10.1016/j.mee.2018.04.007.

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Tran, Nhu Hoa Thi, Phuong Que Do Tran, Bach Thang Phan, Hanh Kieu Thi Ta, Ngoc Xuan Dat Mai, Lai Thi Hoa, Thanh Van Thi Tran, and Dung Van Hoang. "Gold nanoparticles enhanced fluorescence for highly sensitive biosensors based on localized surface plasmon resonance applied in determination C-reactive protein." Science and Technology Development Journal 24, no. 1 (March 17, 2021): 1862–69. http://dx.doi.org/10.32508/stdj.v24i1.2489.

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Introduction: C-reactive protein (CPR) is known as an inflammation marker related to numerous pathology. Optical biosensor based on the fluorescence dyed is widely used in diagnosis. There are still limitations on the fluorescence signal detection due to the photobleaching effect. The localized surface plasmon resonance (LSPR) performed by gold nanoparticles (Au NPs) is testified for the enhancement of photo-signal gathered from the dye molecules. Methods: In this study, Au NPs were used for their significant optical properties and biocompatibility additionally. The seed-mediated synthesis method provided stable NPs with all the essential qualities. A series of modification steps were done on a glass substrate before the bio-bonding for fluorescence-based sensing by a transmission mode (T-mode) detection system which is introduced for the first time in Viet Nam. Results: The synthetic Au NPs in nanosphere structure evinced the absorbance at a maximum wavelength is 521 nm. All the followed alterations showed the accomplishment in forming the in need linking proved through the basic analysis methods. Finally, CRP with the Alexa 488 dye was observed for average at 4.8 folds of enhancement factor compared between the Au NPs coating and non-coating substrate detected by the T-mode system. The low coefficient of variation at under 0.7% appeared for the repeatability and stability of this sensor. Conclusion: The completely modern approach of the T-mode system combined with the LSPR applied in fluorescence sensors enhanced is developed successfully. Also, the future prospect of this designed sensing method is promising by changing the materials' structures and ingredients. Keywords: LSPR, gold nanoparticles, fluorescence enhancement, C-reaction protein, optical biosensors

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Meira, Diana I., Manuela Proença, Rita Rebelo, Ana I. Barbosa, Marco S. Rodrigues, Joel Borges, Filipe Vaz, Rui L. Reis, and Vitor M. Correlo. "Chitosan Micro-Membranes with Integrated Gold Nanoparticles as an LSPR-Based Sensing Platform." Biosensors 12, no. 11 (November 1, 2022): 951. http://dx.doi.org/10.3390/bios12110951.

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Abstract:

Currently, there is an increasing need to develop highly sensitive plasmonic sensors able to provide good biocompatibility, flexibility, and optical stability to detect low levels of analytes in biological media. In this study, gold nanoparticles (Au NPs) were dispersed into chitosan membranes by spin coating. It has been demonstrated that these membranes are particularly stable and can be successfully employed as versatile plasmonic platforms for molecular sensing. The optical response of the chitosan/Au NPs interfaces and their capability to sense the medium’s refractive index (RI) changes, either in a liquid or gas media, were investigated by high-resolution localized surface plasmon resonance (HR-LSPR) spectroscopy, as a proof of concept for biosensing applications. The results revealed that the lowest polymer concentration (chitosan (0.5%)/Au-NPs membrane) presented the most suitable plasmonic response. An LSPR band redshift was observed as the RI of the surrounding media was incremented, resulting in a sensitivity value of 28 ± 1 nm/RIU. Furthermore, the plasmonic membrane showed an outstanding performance when tested in gaseous atmospheres, being capable of distinguishing inert gases with only a 10−5 RI unit difference. The potential of chitosan/Au-NPs membranes was confirmed for application in LSPR-based sensing applications, despite the fact that further materials optimization should be performed to enhance sensitivity.

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Journal articles on the topic 'LSPR sensors'

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