Journal articles: 'Localized Surface Plasmon Resonance signals'

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Hwang, Hyunsik, and Hyunjoon Song. "Nanoscale reaction monitoring using localized surface plasmon resonance scatterometry." Chemical Physics Reviews 3, no. 3 (September 2022): 031301. http://dx.doi.org/10.1063/5.0090949.

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Heterogeneous reactions are highly dependent upon the local structure and environment of the catalyst surface within a nanoscale. Among numerous techniques for monitoring heterogeneous reactions, dark-field microscopy offers reliable data regardless of specific reaction conditions. In addition, plasmonic nanoprobes provide high sensitivity in a sub-wavelength resolution due to localized surface plasmon resonances susceptible to the dielectric change of objects and surroundings. By clever reaction cell design and data analysis, nanoparticle signals can be parallelly analyzed under variable reaction conditions in a controlled manner. This technique effectively measures the heterogeneity of individual nanoparticles for reaction monitoring. A wide range of chemical and electrochemical reactions have been monitored in situ and in operando at a single-particle level in this way. The advancement of localized surface plasmon scatterometry with simulation techniques approaches sub-particle accuracy in a high temporal resolution up to microseconds. Combining other in situ spectroscopic methods would make dark-field scatterometry a versatile tool for various reaction monitoring and sensing applications.

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Tran, Vien Thi, and Heongkyu Ju. "Fluorescence Enhancement via Dual Coupling of Dye Molecules with Silver Nanostructures." Chemosensors 9, no. 8 (August 10, 2021): 217. http://dx.doi.org/10.3390/chemosensors9080217.

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We demonstrate the enhancement of fluorescence emitted from dye molecules coupled with two surface plasmons, i.e., silver nanoparticles (AgNPs)-induced localized surface plasmons (LSP) and thin silver (Ag) film supported surface plasmons. Excitation light is illuminated to a SiO2 layer that contains both rhodamine 110 molecules and AgNPs. AgNPs enhances excitation rates of dye molecules in their close proximity due to LSP-induced enhancement of local electromagnetic fields at dye excitation wavelengths. Moreover, the SiO2 layer on one surface of which a 50 nm-thick Ag film is coated for metal cladding (air on the other surface), acts as a waveguide core at the dye emission wavelengths. The Ag film induces the surface plasmons which couple with the waveguide modes, resulting in a waveguide-modulated version of surface plasmon coupled emission (SPCE) for different SiO2 thicknesses in a reverse Kretschmann configuration. We find that varying the SiO2 thickness modulates the fluorescent signal of SPCE, its modulation behavior being in agreement with the theoretical simulation of thickness dependent properties of the coupled plasmon waveguide resonance. This enables optimization engineering of the waveguide structure for enhancement of fluorescent signals. The combination of LSP enhanced dye excitation and the waveguide-modulated version of SPCE may offer chances of enhancing fluorescent signals for a highly sensitive fluorescent assay of biomedical and chemical substances.

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Tatsuma, Tetsu, Yu Katagi, Satoshi Watanabe, Kazutaka Akiyoshi, Tokuhisa Kawawaki, Hiroyasu Nishi, and Emiko Kazuma. "Direct output of electrical signals from LSPR sensors on the basis of plasmon-induced charge separation." Chemical Communications 51, no. 28 (2015): 6100–6103. http://dx.doi.org/10.1039/c5cc01020a.

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Potentiometric and conductometric sensors based on localized surface plasmon resonance that do not require light to pass through the sample solution were developed and applied to coloured and turbid samples.

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Lim, Hyunsoo, Dabum Kim, Yena Kim, Tomota Nagaura, Jungmok You, Jeonghun Kim, Hyun-Jong Kim, Jongbeom Na, Joel Henzie, and Yusuke Yamauchi. "A mesopore-stimulated electromagnetic near-field: electrochemical synthesis of mesoporous copper films by micelle self-assembly." Journal of Materials Chemistry A 8, no. 40 (2020): 21016–25. http://dx.doi.org/10.1039/d0ta06228f.

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The optimized mesoporous Cu films lead to strong localized surface plasmon resonances (LSPRs) due to their intertwined 3D natures and pores, resulting in strong surface-enhanced Raman spectroscopy (SERS) signals.

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Qi, Zhengqing, Jinhuan Li, Peng Chen, Lingling Zhang, and Ke Ji. "Tunable High-Q Factor Substrate for Selectively Enhanced Raman Scattering." Photonics 9, no. 10 (October 11, 2022): 755. http://dx.doi.org/10.3390/photonics9100755.

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Most Surface-enhanced Raman scattering (SERS) substrates enhance all the Raman signals in a relative broad spectral range. The substrates enhance both the interested and background signals together. To improve the identification of target molecules from numerous background ones, substrates with multi high-quality (Q) factor resonance wavelengths can be designed to achieve the selective enhancement of specific Raman transitions. When the resonance frequencies are modulated to match the excitation and Raman scattering frequencies, the detection of the target molecule can be more effective. In this paper, we design a tunable high-Q SERS substrate with periodic silver bowtie nanoholes on silica spacer and silver film. The substrate possessed three high-Q and high electric field resonance modes, which resulted from the interaction of the localized surface plasmon resonance (LSPR) of the bowtie nanoholes, the surface plasmon polariton (SPP) of the period bowtie nanoholes and the Fabry–Perot (FP) resonance between the bowtie and silver film bottom. The interaction between these resonance modes resulted in not only a higher quality (Q) factor, but also a higher electric field, which can be employed to realize a potential substrate in high-sensitivity and selective-detection fields.

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Meng, Lingyan, and Zhilin Yang. "Directional surface plasmon-coupled emission of tilted-tip enhanced spectroscopy." Nanophotonics 7, no. 7 (June 13, 2018): 1325–32. http://dx.doi.org/10.1515/nanoph-2018-0033.

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AbstractUnderstanding the spatial radiation pattern in tip-enhanced spectroscopy (TES) is crucial for plasmon-enhanced spectroscopy, chemical analysis and biochemical sensing. Although the TES technique has many excellent advantages, there is still room for improvement in terms of detection sensitivity. In this paper, we theoretically demonstrate the tip-tilted TES configuration featuring high directivity by using side illumination-collection condition. Taking full advantage of the characteristic of high directional emission ascribed to the far-field interference between localized surface plasmon resonance (LSPR) and surface plasmon polariton (SPP) modes, the collection efficiency of TES signals can be largely improved, greatly boosting the detection sensitivity of TES technology. Our theoretical results not only provide a deep understanding of the underlying physical mechanism of the directional surface plasmon-coupled emission of TES, but also serves as a promising guide for the rational construction of a highly efficient TES platform at the single molecular level.

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Song, Wen-Bo, Yun Qi, Xiao-Peng Zhang, Ming-Li Wan, and Jinna He. "Controlling the interference between localized and delocalized surface plasmons via incident polarization for optical switching." International Journal of Modern Physics B 32, no. 16 (June 28, 2018): 1850194. http://dx.doi.org/10.1142/s0217979218501941.

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Surface plasmons supported by various metallic nanostructures have given rise to several significant breakthroughs in the field of integrated photonic devices due to its ability to effectively confine and enhance optical field in subwavelength volume. In particular, the demand to actively control optical responses of plasmonic systems becomes urgent for the miniaturization of signal processing devices, surface-enhanced Raman scattering (SERS) substrates and biochemical sensors. In this paper, we systematically investigate the plasmon modes as well as their interaction in a layered nanostructure composed of a periodically-arranged radiative nanoring and a metallic ground plane, as well as a thin insulating spacer. A tunable transparent peak on the background of the broadband plasmon resonance emerges in the reflection spectrum as changing the periodicity of nanoparticle array, a plasmonic analogue of electromagnetically induced transparency (EIT). Owing to the structural symmetry of the rings, we demonstrate a new scheme of controlling the interference between localized and delocalized plasmons by means of incident polarization and believe that the proposed metasurface may find applications in optical switching if the polarization-controlled components are introduced.

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Zhang, Yan, Bingyu Wang, Shihe Yang, Lidong Li, and Lin Guo. "Facile synthesis of spinous-like Au nanostructures for unique localized surface plasmon resonance and surface-enhanced Raman scattering." New Journal of Chemistry 39, no. 4 (2015): 2551–56. http://dx.doi.org/10.1039/c4nj01769b.

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Spinous-like gold nanostructures were prepared using a wet chemistry method, and the intensities of the UV-Vis and SERS signals of the nanostructures were determined to be greatly enhanced by the presence of the spinous shapes.

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Singh, Ranjit, and Sanjeev Dewra. "Performance Analysis of Localized Surface Plasmon Resonance Sensor with and Without Bragg Grating." Journal of Optical Communications 41, no. 1 (December 18, 2019): 45–50. http://dx.doi.org/10.1515/joc-2017-0141.

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Abstract The performance of localized surface plasmon resonance-based sensor with and without Bragg grating by using finite difference time domain method is evaluated with nanoparticles used at the tip of optical fiber. The proposed sensor has been analyzed in terms of refractive index (RI) sensitivity and signal-to-noise ratio (SNR). It is observed that the RI sensitivity of surface plasmon resonance sensor is 240 nm/RIU with and without grating as RI of surrounding varies from 1.4 to 1.5. It is found that the value of SNR is 0.875 RIU→1 without grating and 2.75 RIU→1 with grating. So there is an improvement in the SNR when the Bragg grating is inscribed within the core of the fiber.

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Zhou, Bei, Feng Gu, Yingzheng Liu, and Di Peng. "Signal Enhancement of Pressure-Sensitive Film Based on Localized Surface Plasmon Resonance." Sensors 21, no. 22 (November 17, 2021): 7627. http://dx.doi.org/10.3390/s21227627.

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Pressure-sensitive films have been used for measurement in micro flow, but thin films have very limited intensity, resulting in poor signal-noise ratio (SNR). This paper presents a pressure-sensitive film whose emission signal is enhanced by silver nanoparticles (AgNPs) based on localized surface plasmon resonance (LSPR). Electronic beam evaporator and annealing furnace are used to fabricate silver nanotexture surface. PtTFPP and polystyrene are dissolved in toluene and then spin-coated on the silver nanotexture surface to prepare the pressure-sensitive films. Signal enhancement of film with AgNPs due to LSPR is analyzed and enhancement effect of samples with different particle sizes and spacer thickness are compared. Pressure and temperature calibrations are performed to assess the sensing performance of pressure-sensitive films. Pressure-sensitive films with AgNPs demonstrate signal enhancement due to LSPR and show promise for measurement in micro flow.

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Lou, Zhi Chao, Jin Qiang Sun, Jin Feng Wan, Xiao Hong Zhang, Hai Qian Zhang, and Ning Gu. "Quick and Sensitive Detection of Prion Disease-Associated Isoform (PrP^Sc) Using a Novel Gold Surface/PrP^Sc/Gold Nanoparticles Sandwich SPR Detection Assay." Journal of Nano Research 48 (July 2017): 18–28. http://dx.doi.org/10.4028/www.scientific.net/jnanor.48.18.

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Prion protein has drawn great attention due to its pathological potential to prion diseases. Discriminate and detection of the trace quantities PrPSc is an important measure for prion disease diagnosis at the presymptomatic stage. In this study, we developed a novel sandwich surface plasmon resonance (SPR) assay for the detection of PrPSc, involving bare gold surfaces and bare gold nanoparticles. PrPSc can be captured by the SPR sensing surface via a surface assisted coupling reaction between its intra-molecular disulfide bond and the gold atoms, while PrPC cannot bind to the gold surface strongly. The gold nanoparticles were proved to amplify the SPR detection signals via the coupling of their localized surface plasmon (LSP) with the propagating plasmon on the SPR gold surface. Our results confirmed that the bare SPR gold surface successfully captured the PrPSc from the solution with a LOD of 0.5ng/mL and a linear detection range from 0.5ng/mL to 500ng/mL. Injecting the gold nanoparticles after PrPSc yielded a dramatic enhancement of signal, with a lower LOD of 0.001ng/mL and a linear detection range from 0.001ng/mL to 10ng/mL. The gold nanoparticles permitted 4 to 322-fold increase of the signals. The required detection time was controlled in 15 min. PrPC, cys-protein G and their mixtures with PrPSc, were also detected via this sandwich SPR detection assay. Atomic force microscope (AFM) was used to evaluate the surface morphology of the SPR gold substrate after the detection. All the obtained results suggested that this novel SPR sandwich detection assay in our work was efficient, sensitive and specific for the detection of trace PrPSc

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Yu, Jeong Seon, Minsik Kim, Sanghoon Kim, Dong Han Ha, Bong Hyun Chung, Sang Jeon Chung, and Jong-Sung Yu. "Characteristics of Localized Surface Plasmon Resonance of Nanostructured Au Patterns for Biosensing." Journal of Nanoscience and Nanotechnology 8, no. 9 (September 1, 2008): 4548–52. http://dx.doi.org/10.1166/jnn.2008.ic20.

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Periodic arrays of pseudotetrahedal-shaped gold nanoparticles were fabricated using nanosphere lithography (NSL) and examined for localized surface plasmon resonance (LSPR). The dependence of the LSPR on particle size of the periodic gold nanostructures was explored for potential application as a new biosensor. With increasing size and height of the Au nanoparticles, the absorption peak of the LSPR shifts to the longer wavelength and becomes relatively sharper. With thinner metal deposition or finer Au nanostructure, the absorption signal varies more sensitively for the changes in the Au particle size. The binding affinity study for biotin-streptavidine system on the Au nanopatterns resulted in blue-shifted absorption signal, opening up the possibility of the nanostructured Au pattern as a new LSPR biosensor.

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Zhang, Jie, Yu Lin Chen, Tuo Fan, and Yong Zhu. "Large Area Au Decorated Multi-Walled CNTs Film for Surface Enhanced Raman Scattering." Key Engineering Materials 562-565 (July 2013): 826–31. http://dx.doi.org/10.4028/www.scientific.net/kem.562-565.826.

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We reported on a study upon a Surface-enhanced Raman Scattering (SERS) substrate produced from a large area multi-walled carbon nanotube (MWCNT) films decorated with Au nanoparticles. The morphology and spectrum of the MWCNTs/Au composite structure was characterized with scanning electron microscopy and spectrophotometer. The SERS signals of Rhodamine 6G (R6G) absorbed on the substrate were improved, which could contribute to the enlarged surface area for adsorption of molecules and Localized Plasmon Resonance Effect. The results indicated that it is potential to produce sensitive SERS substrates via further fine-tuning of size, shape of the nanostructure.

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Abdulhalim, Ibrahim. "Coupling configurations between extended surface electromagnetic waves and localized surface plasmons for ultrahigh field enhancement." Nanophotonics 7, no. 12 (November 26, 2018): 1891–916. http://dx.doi.org/10.1515/nanoph-2018-0129.

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AbstractLocal enhancement of electromagnetic (EM) fields near dielectric and metallic surfaces is usually associated with the existence of a confined EM wave at least in one direction. This phenomenon finds applications in enhancing optical spectroscopic signals, optical emission, nonlinear optical processes, biosensing, imaging contrast and superresolution, photovoltaics response, local heating, photocatalysis, and enhanced efficiency of optoelectronic devices. A well-known example is when the surface electromagnetic wave (SEW) is excited at the interface of two media, the field gets enhanced normally to that interface. This article reviews the different configurations revealing enhanced EM fields, particularly those giving ultrahigh enhancement, such as when a localized SEW is excited not from free space but via an extended SEW. Of particular interest are surface plasmon waves (SPWs) excited at the surface of metal-dielectric and particularly when exciting localized SPWs using extended ones. The latter case so far gave the highest local field enhancement; however, configurations involving Bloch SEWs, guided mode resonances, and cavity resonances have also been shown to give significant enhancement when used to excite localized surface plasmons. With this strategy, field enhancement by more than an order of magnitude can be attained. Using this ultrahigh enhancement, the strong coupling experiments between molecules and the intense optical field will be possible and new devices may emerge from those new methodologies for ultrahigh sensitive sensing for environmental and medical applications, as well as for improved optoelectronic devices.

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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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Chegel, V. I., A. M. Lopatynskyi, V. K. Lytvyn, P. V. Demydov, J. P. Martínez-Pastor, R. Abargues, E. A. Gadea, and S. A. Piletsky. "Localized surface plasmon resonance nanochips with molecularly imprinted polymer coating for explosives sensing." Semiconductor Physics, Quantum Electronics and Optoelectronics 23, no. 04 (November 19, 2020): 431–36. http://dx.doi.org/10.15407/spqeo23.04.431.

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Sensor elements based on localized surface plasmon resonance phenomenon in arrays of Au nanostructures on glass substrates (nanochips) with molecularly imprinted acrylamide copolymer coating have been proposed for explosives analogues sensing in liquid and vapor phase. Nanochips exhibited detection limits of 1 pM in aqueous solution and 0.1 ppm in gaseous state against 4-nitrophenol. Vapor phase sensing of 4-nitrotoluene, 1-nitronaphthalene and 5-nitroisoquinoline using the developed 4-nitrophenol-imprinted plasmonic nanochips demonstrated partially selective response with time to signal saturation starting from 2 minutes.

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Ghoshal, S. K., Asmahani Awang, M. R. Sahar, and R. Arifin. "Gold Nanoparticles Stimulated Surface Plasmon Resonance Effects in Erbium-Zinc-Sodium-Tellurite Glass." Materials Science Forum 846 (March 2016): 52–57. http://dx.doi.org/10.4028/www.scientific.net/msf.846.52.

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Modifying the optical characteristics of rare earth (RE) doped inorganic glasses by stimulating surface plasmon resonance (SPR) via controlled growth of metal nanoparticles (NPs) is an outstanding quest in glass plasmonics. Glasses with composition 70TeO2-20ZnO-10Na2O-(x)Er2O3-(y)Au (x = 0.0 and 1.0 mol%; y = 0.0 and 0.6 mol% both in excess) are synthesized using melt-quenching technique and characterized. Influences of heat treatment temperature on the growth of Au NPs and their subsequent impacts on Raman spectral features modifications are inspected. The amorphous nature of glass is confirmed by using XRD. TEM reveal the non-spherical Au NPs with average diameter vary from 7.4 to 10.3 nm. Surface plasmon band is evidenced around 627 - 632 nm. Raman spectra demonstrate the presence of Er-O and Zn-O bond, anti-symmetric vibrations of Te-O-Te bonds and stretching modes of non-bonded oxygen exists in TeO3 and TeO3+1 unit. The amplifications in Raman signals by a factor of 1.39, 1.40, 0.88 and 1.29 and 1.25 corresponding to the peak centered at 262, 382, 536, 670 and 725 cm-1 are attributed to the contribution of a surface plasmon (SP) generating a strong, localized and secondary field. The excellent features of the results suggest that our systematic method of controlled NPs growth may constitute a basis for improving the spectral features of tellurite glasses useful for the development of efficient and economic up-converted lasers.

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Asing, Md Eaqub Ali, and Sharifah Bee Abd Hamid. "SERS-Modeling in Molecular Sensing." Advanced Materials Research 1109 (June 2015): 223–26. http://dx.doi.org/10.4028/www.scientific.net/amr.1109.223.

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Surface enhanced Raman spectroscopy (SERS) is an ultrasensitive vibrational spectroscopic technique that useful tools in detecting biomolecules at near or on the surface of plasmonic nanostructures. Unique physicochemical and optical properties of noble metal nanostructures allow the assimilation of biomolecular probes and exhibit distinctive spectra, prompting the development of a plethora of biosensing platforms in molecular diagnostics. In SERS biosensor, signal to noise ration such as recognition and transducer elements that provide fingerprint spectrum at the lower limit of detection with specific binding or hybridized event, increasing reliability and sensitivity. Since the localized surface plasmon resonance (LSPR) of nanoparticle lies at the heart of SERS. It is essential to control all of the LSPR influencing factors in highly sensitivity signal strength that ensures reproducibility of SERS signals. SERS active substrates, transducer elements, metal surfaces modification, interparticle spacing, dielectric environment and selection of biorecognition molecules contribute in SERS signal strength. Modified metal structure with bioprobe and Raman reporter molecules provides a strong signature fingerprints that surely contribute to noble biosensor structural designing. We reviewed here ideal fabrication of nanostructure for SERS application in molecular sensing research fields.

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Huang, Haowen, Caiting Qu, Xuanyong Liu, Shaowen Huang, Zhongjian Xu, Yingjie Zhu, and Paul K. Chu. "Amplification of localized surface plasmon resonance signals by a gold nanorod assembly and ultra-sensitive detection of mercury." Chemical Communications 47, no. 24 (2011): 6897. http://dx.doi.org/10.1039/c1cc12137e.

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Abumazwed, Ahmed, Wakana Kubo, Chen Shen, Takuo Tanaka, and Andrew G. Kirk. "Projection method for improving signal to noise ratio of localized surface plasmon resonance biosensors." Biomedical Optics Express 8, no. 1 (December 23, 2016): 446. http://dx.doi.org/10.1364/boe.8.000446.

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Liu, Zhenchao, Jinlong He, and Sailing He. "Characterization and Sensing of Inert Gases with a High-Resolution SPR Sensor." Sensors 20, no. 11 (June 10, 2020): 3295. http://dx.doi.org/10.3390/s20113295.

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It is generally difficult to characterize inert gases through chemical reactions due to their inert chemical properties. The phase interference-sensing system based on high-resolution surface plasmon resonance (SPR) has an excellent refractive index detection limit. Based on this, this paper presents a simple and workable method for the characterization and detection of inert gases. The phase of light for the present SPR sensor is more sensitive to the change in the external dielectric environment than an amplitude SPR sensor. The limit of detection (LOD) is usually in the order of 10−6 to 10−7 RIU, which is superior to LSPR (Localized Surface Plasmon Resonance) sensors and traditional SPR sensors. The sensor parameters are simulated and optimized. Our simulation shows that a 36 nm-thick gold film is more suitable for the SPR sensing of inert gases. By periodically switching between the two inert gases, helium and argon, the resolution of the system is tested. The SPR sensing system can achieve distinguishable difference signals, enabling a clear distinction and characterization of helium and argon. The doping of argon in helium has a detection limit of 1098 ppm.

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Barbillon, Grégory. "Nanoplasmonics in High Pressure Environment." Photonics 7, no. 3 (July 28, 2020): 53. http://dx.doi.org/10.3390/photonics7030053.

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An explosion in the interest for nanoplasmonics has occurred in order to realize optical devices, biosensors, and photovoltaic devices. The plasmonic nanostructures are used for enhancing and confining the electric field. In the specific case of biosensing, this electric field confinement can induce the enhancement of the Raman signal of different molecules, or the localized surface plasmon resonance shift after the detection of analytes on plasmonic nanostructures. A major part of studies concerning to plasmonic modes and their application to sensing of analytes is realized in ambient environment. However, over the past decade, an emerging subject of nanoplasmonics has appeared, which is nanoplasmonics in high pressure environment. In last five years (2015–2020), the latest advances in this emerging field and its application to sensing were carried out. This short review is focused on the pressure effect on localized surface plasmon resonance of gold nanosystems, the supercrystal formation of plasmonic nanoparticles stimulated by high pressure, and the detection of molecules and phase transitions with plasmonic nanostructures in high pressure environment.

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Shen, Tsu-Wang, Ting-Ku Ou, Bo-Yan Lin, and Yi-Hsin Chien. "Plasmonic Gold Nanomaterials as Photoacoustic Signal Resonant Enhancers for Cysteine Detection." Nanomaterials 11, no. 8 (July 23, 2021): 1887. http://dx.doi.org/10.3390/nano11081887.

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The development of photoacoustic systems is important for the real-time detection of cysteine (Cys), a biothiol in biological systems that serves as a significant biomarker for human health. Advanced photoacoustic (PA) signals with colloidal plasmonic Au nanomaterials rely on the efficient conversion of light to energy waves under moderately pulsed laser irradiation. In this study, we synthesized Cys-capped Au nanorods (Au@Cys NRs) and Cys-capped Au nanoparticles (Au@Cys NPs) through a conjugate of three Cys concentrations (10, 100, and 1000 μM). These plasmonic Au nanomaterials can be used as a PA resonance reagent due to their maximum localized surface plasmon resonance (LSPR) absorption bands at 650 nm and 520 nm in Au NRs and Au NPs, respectively. Subsequently, the PA signals were noticeably increased proportionally to the concentrations in the Au@Cys NRs and Au@Cys NPs under 658 nm and 520 nm laser irradiation, respectively, according to our portable photoacoustic system. Furthermore, PA signal amplitudes in Cys detection are boosted by ~233.01% with Au@Cys NRs and ~102.84% with Au@Cys NPs enhancement, compared to free Cys, according to ultrasound transducers at frequencies of 3 MHz.

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Lee, Sang-Nam, Jin-Ha Choi, Hyeon-Yeol Cho, and Jeong-Woo Choi. "Metallic Nanoparticle-Based Optical Cell Chip for Nondestructive Monitoring of Intra/Extracellular Signals." Pharmaceutics 12, no. 1 (January 7, 2020): 50. http://dx.doi.org/10.3390/pharmaceutics12010050.

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The biosensing platform is noteworthy for high sensitivity and precise detection of target analytes, which are related to the status of cells or specific diseases. The modification of the transducers with metallic nanoparticles (MNPs) has attracted attention owing to excellent features such as improved sensitivity and selectivity. Moreover, the incorporation of MNPs into biosensing systems may increase the speed and the capability of the biosensors. In this review, we introduce the current progress of the developed cell-based biosensors, cell chip, based on the unique physiochemical features of MNPs. Mainly, we focus on optical intra/extracellular biosensing methods, including fluorescence, localized surface plasmon resonance (LSPR), and surface-enhanced Raman spectroscopy (SERS) based on the coupling of MNPs. We believe that the topics discussed here are useful and able to provide a guideline in the development of new MNP-based cell chip platforms for pharmaceutical applications such as drug screening and toxicological tests in the near future.

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Szlachetko, Kamil, Piotr Piotrowski, Katarzyna Sadecka, Paweł Osewski, Dobrosława Kasprowicz, and Dorota A. Pawlak. "Selective surface-enhanced Raman scattering in a bulk nanoplasmonic Bi2O3-Ag eutectic composite." Nanophotonics 9, no. 14 (July 8, 2020): 4307–14. http://dx.doi.org/10.1515/nanoph-2020-0281.

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AbstractA recent surge of interest in surface-enhanced Raman scattering (SERS) has stimulated the search for new systems that can be utilized to fabricate high-performance optical devices. However, the two-dimensional design of the vast majority of SERS-based assemblies has significantly hindered their real-life applicability, motivating the development of three-dimensional volumetric materials. Here, we report selective SERS observed in a volumetric Bi2O3-Ag eutectic composite obtained by the micro-pulling-down method utilizing directional solidification of eutectics. The enhancement of the Raman signal originates from the localized surface plasmon resonance, LSPR, resulting from silver nanoparticles embedded in the composite. The plasmonic origin of the enhancement is confirmed by characteristic features, such as (i) an enhancement magnitude >103, (ii) the correspondence between the Raman bands’ intensity upon excitation by different wavelengths and the localized surface plasmon resonance (LSPR) intensity, and (iii) the occurrence of overtones, which are absent in the as-grown material that does not exhibit LSPR. The examined Bi2O3-Ag eutectic-based composite is obtained by directional solidification using a simple crystal growth technique. It is the first case of a bulk SERS-active material fabricated by crystal growth techniques, which opens new perspectives towards scalable three-dimensional optical elements with tunable properties based on Raman scattering.

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Liu, Jingyi, Lianchun Long, and Yang Yang. "Modeling of Enhanced Polar Magneto-Optic Kerr Effect by Surface Plasmons in Au Bowtie Arrays." Nanomaterials 13, no. 2 (January 6, 2023): 253. http://dx.doi.org/10.3390/nano13020253.

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The weak magneto-optical (MO) signal of traditional MO materials is indeed an important issue for their further practical applications. Although many strategies have been proposed to improve the MO effect, hybridization with noble metal nanostructures is a promising route in recent years due to the high localized-surface plasmon resonances (LSPR) effect. A new magneto-optical surface plasmon resonance (MOSPR) structure hybrid with Au bowtie arrays is proposed to increase the measuring range of the polar magneto-optical Kerr effect (PMOKE) and the quality factor through the LSPR effect. It is verified by a numerical simulation of the finite element method (FEM). The optimized parameters were found by modulating the shape and geometric dimensions. Owing to the significant LSPR from the Au bowties, a PMOKE amplification signal spectrum with narrow linewidth, and a high amplitude with high-sensing performance was achieved. Compared with the bare magnetic film alone, by optimizing the relevant parameters of the LSPR structure, the maximum signal increases 3255 times, and the quality factor can be greatly improved, which would provide important guidance and help for the practical application of MO devices.

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Lee, Tae-Han, Seung-Woo Lee, Ji-Ae Jung, Junhyoung Ahn, Min-Gon Kim, and Yong-Beom Shin. "Signal Amplification by Enzymatic Reaction in an Immunosensor Based on Localized Surface Plasmon Resonance (LSPR)." Sensors 10, no. 3 (March 12, 2010): 2045–53. http://dx.doi.org/10.3390/s100302045.

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Aldosari, Fahad M. M. "Characterization of Labeled Gold Nanoparticles for Surface-Enhanced Raman Scattering." Molecules 27, no. 3 (January 28, 2022): 892. http://dx.doi.org/10.3390/molecules27030892.

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Noble metal nanoparticles (NP) such as gold (AuNPs) and silver nanoparticles (AgNPs) can produce ultrasensitive surface-enhanced Raman scattering (SERS) signals owing to their plasmonic properties. AuNPs have been widely investigated for their biocompatibility and potential to be used in clinical diagnostics and therapeutics or combined for theranostics. In this work, labeled AuNPs in suspension were characterized in terms of size dependency of their localized surface plasmon resonance (LSPR), dynamic light scattering (DLS), and SERS activity. The study was conducted using a set of four Raman labels or reporters, i.e., small molecules with large scattering cross-section and a thiol moiety for chemisorption on the AuNP, namely 4-mercaptobenzoic acid (4-MBA), 2-naphthalenethiol (2-NT), 4-acetamidothiophenol (4-AATP), and biphenyl-4-thiol (BPT), to investigate their viability for SERS tagging of spherical AuNPs of different size in the range 5 nm to 100 nm. The results showed that, when using 785 nm laser excitation, the SERS signal increases with the increasing size of AuNP up to 60 or 80 nm. The signal is highest for BPT labelled 80 nm AuNPs followed by 4-AATP labeled 60 nm AuNPs, making BPT and 4-AATP the preferred candidates for Raman labelling of spherical gold within the range of 5 nm to 100 nm in diameter.

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D’Acunto, Mario. "In Situ Surface-Enhanced Raman Spectroscopy of Cellular Components: Theory and Experimental Results." Materials 12, no. 9 (May 13, 2019): 1564. http://dx.doi.org/10.3390/ma12091564.

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In the last decade, surface-enhanced Raman spectroscopy (SERS) met increasing interest in the detection of chemical and biological agents due to its rapid performance and ultra-sensitive features. Being SERS a combination of Raman spectroscopy and nanotechnology, it includes the advantages of Raman spectroscopy, providing rapid spectra collection, small sample sizes, characteristic spectral fingerprints for specific analytes. In addition, SERS overcomes low sensitivity or fluorescence interference that represents two major drawbacks of traditional Raman spectroscopy. Nanoscale roughened metal surfaces tremendously enhance the weak Raman signal due to electromagnetic field enhancement generated by localized surface plasmon resonances. In this paper, we detected label-free SERS signals for arbitrarily configurations of dimers, trimers, etc., composed of gold nanoshells (AuNSs) and applied to the mapping of osteosarcoma intracellular components. The experimental results combined to a theoretical model computation of SERS signal of specific AuNSs configurations, based on open cavity plasmonics, give the possibility to quantify SERS enhancement for overcoming spectral fluctuations. The results show that the Raman signal is locally enhanced inside the cell by AuNSs uptake and correspondent geometrical configuration generating dimers are able to enhance locally electromagnetic fields. The SERS signals inside such regions permit the unequivocal identification of cancer-specific biochemical components such as hydroxyapatite, phenylalanine, and protein denaturation due to disulfide bonds breaking between cysteine links or proline.

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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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Fujiwara, Satoko, Daiki Kawasaki, Kenji Sueyoshi, Hideaki Hisamoto, and Tatsuro Endo. "Gold Nanocone Array with Extensive Electromagnetic Fields for Highly Reproducible Surface-Enhanced Raman Scattering Measurements." Micromachines 13, no. 8 (July 27, 2022): 1182. http://dx.doi.org/10.3390/mi13081182.

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Surface-enhanced Raman scattering (SERS) is a technique used to distinguish the constitution of disease-related biomarkers in liquid biopsies, such as exosomes and circulating tumor cells, without any recognition elements. Previous studies using metal nanoparticle aggregates and angular nanostructures have achieved the detection of various biomarkers owing to strong hot spots and electromagnetic (EM) fields by localized surface plasmon resonance (LSPR). Although these SERS platforms enable significant enhancement of Raman signals, they still have some problems with the fabrication reproducibility of platforms in obtaining reproducible SERS signals. Therefore, highly reproducible fabrication of SERS platforms is required. Here, we propose the application of a polymer-based gold (Au) nanocone array (Au NCA), which extensively generates an enhanced EM field near the Au NCA surface by LSPR. This approach was experimentally demonstrated using a 785 nm laser, typically used for SERS measurements, and showed excellent substrate-to-substrate reproducibility (relative standard deviation (RSD) < 6%) using an extremely simple fabrication procedure and very low laser energy. These results proved that a Au NCA can be used as a highly reproducible SERS measurement to distinguish the constitution of biomarkers.

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Sun, Xiaoli, Qingchuan Ye, Yi Liu, Wenqing Sun, Chi Pang, Yuechen Jia, and Feng Chen. "Plasmon-enhanced Raman scattering of 2D materials via embedded silver nanoparticles in glass." Journal of Applied Physics 133, no. 8 (February 28, 2023): 084304. http://dx.doi.org/10.1063/5.0138584.

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Localized surface plasmon resonance from metallic nanoparticles (NPs) under optical excitation brings out intriguing applications in photonics. We realize plasmon-enhanced Raman scattering of two-dimensional (2D) materials (up to 19 times of magnitude for SnSe2 and 12 times for MoS2) via embedded silver nanoparticles in fused silica glass (hereby Ag NPs:glass), suggesting that the fabricated ion-modified multifunctional substrate shows a good compatibility that couple with 2D nanosheets. Moreover, the existence of insulating layers of SiO2 blocks the direct electron transfer and protects the intrinsic properties of surface materials, the Ag NPs:glass substrate exhibits excellent environmental stability and reusability, maintaining higher enhancement ability after a number of repeated uses. Our work opens up a novel route to develop reusable functional substrates for practical applications toward the weak-signal detection and label-free enhanced Raman scattering.

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Toftegaard, Rasmus, Jacob Arnbjerg, Huaiping Cong, Hossein Agheli, Duncan S. Sutherland, and Peter R. Ogilby. "Metal nanoparticle-enhanced radiative transitions: Giving singlet oxygen emission a boost." Pure and Applied Chemistry 83, no. 4 (February 23, 2011): 885–98. http://dx.doi.org/10.1351/pac-con-10-09-24.

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The fabrication and use of metal nanoparticles to influence electronic transitions in a given molecule is of growing interest; there is much to be gained by developing and exploiting methods to enhance weak optical signals. Singlet molecular oxygen, O2(a1∆g), which is an important intermediate in many oxidation reactions, particularly in biological systems, is ideally monitored by the 1275-nm O2(a1∆g) → O2(X3Σg–) phosphorescent transition. Unfortunately, the latter is highly forbidden and, as such, often presents a severe limitation in the application of this optical probe. In this paper, we describe how this weak phosphorescent transition can be enhanced by using localized surface plasmons (LSPs) from specially engineered gold nanostructures. In an attempt to elucidate the mechanism of this process, data were recorded from samples in which we decoupled the component of the plasmon resonance that absorbs incident light from the component that scatters incident light. We find that the latter appears to be the feature of significance in the process through which singlet oxygen phosphorescence is enhanced. In this work, we also illustrate how the singlet oxygen system provides an ideal model for a general study of metal-enhanced radiative rate constants.

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Zhang, Xinping. "Plasmon extinguishment by bandedge shift identified as a second-order spectroscopic differentiation." Nanophotonics 10, no. 4 (January 1, 2021): 1329–35. http://dx.doi.org/10.1515/nanoph-2020-0603.

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Abstract Optical excitation of metallic nanostructures induces strong intraband transitions, leaving transient depletion below the Fermi level, which allows transient interband transition to this depletion band. This is equivalent to the lowering of the threshold for interband transitions and pushes the plasmonic band to the red. As a result, localized surface plasmon resonance (LSPR) is “extinguished” or “quenched” around the bandedge, in contrast, the interband optical absorption becomes enhanced and redshifted. The corresponding transient absorption (TA) signals have equal lifetimes and opposite signs. Moreover, the TA spectrum is found to be a second-order differential of the steady-state optical extinction spectrum over the studied band. This is a commonly existing mechanism for metallic nanostructures and verified with gold in this work. Such a discovery is completely different from the optical-excitation-induced redshift of LSPR through enhanced electronic scattering and is important for understanding the ultrafast spectroscopic response of plasmonic nanostructures with clear photophysical insights, supplying solid basis for exploring optical logic device and optical data processing techniques.

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Hao, Xingkai, Jean-Philippe St-Pierre, Shan Zou, and Xudong Cao. "Localized surface plasmon resonance biosensor chip surface modification and signal amplifications toward rapid and sensitive detection of COVID-19 infections." Biosensors and Bioelectronics 236 (September 2023): 115421. http://dx.doi.org/10.1016/j.bios.2023.115421.

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Yukhymchuk, V. O., V. M. Rubish, V. M. Dzhagan, O. M. Hreshchuk, O. F. Isaieva, N. V. Mazur, M. O. Durkot, et al. "Surface-enhanced Raman scattering of As2S3 and Se thin films formed on Au nano-structures." Semiconductor Physics, Quantum Electronics and Optoelectronics 26, no. 1 (March 24, 2023): 049–58. http://dx.doi.org/10.15407/spqeo26.01.049.

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The effect of plasmonic nanostructures (NSs) on the Raman spectra and underlying structural changes in thin chalcogenide films is investigated. Several tens of nanometers thick As 2 S 3 and Se films were deposited by thermal sputtering on glass and surface-enhanced Raman spectroscopy (SERS) substrates based on gold nanostructures for comparison. The films on glass were practically not detectable by the Raman spectroscopy. Using gold NSs as the substrates enabled reliable registration of the Raman spectra of both the As 2 S 3 and Se films. The registered Raman spectra contained all the features usually present in the films with the thicknesses ~1 μm or more. Based on our analysis of the spectra obtained at different excitation wavelengths, we may conclude that the SERS chemical mechanism makes the main contribution to the enhancement of the Raman signal from chalcogenide films. Adjustment of the parameters of SERS substrates to tune their plasmon band position in resonance with the excitation laser radiation enables increasing the plasmonic enhancement contribution. Besides the effect of enhancement, localized plasmon resonance in the gold NSs causes local heating of the chalcogenide film around them leading to local structural transformations, which can be controlled using the Raman spectra.

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Vlieg, Redmar C., and John van Noort. "Multiplexed two-photon excitation spectroscopy of single gold nanorods." Journal of Chemical Physics 156, no. 9 (March 7, 2022): 094201. http://dx.doi.org/10.1063/5.0073208.

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Plasmonic metallic nanoparticles are commonly used in (bio-)sensing applications because their localized surface plasmon resonance is highly sensitive to changes in the environment. Although optical detection of scattered light from single particles provides a straightforward means of detection, the two-photon luminescence (TPL) of single gold nanorods (GNRs) has the potential to increase the sensitivity due to the large anti-Stokes shift and the non-linear excitation mechanism. However, two-photon microscopy and spectroscopy are restricted in bandwidth and have been limited by the thermal stability of GNRs. Here, we used a scanning multi-focal microscope to simultaneously measure the two-photon excitation spectra of hundreds of individual GNRs with sub-nanometer accuracy. By keeping the excitation power under the melting threshold, we show that GNRs were stable in intensity and spectrum for more than 30 min, demonstrating the absence of thermal reshaping. Spectra featured a signal-to-noise ratio of >10 and a plasmon peak width of typically 30 nm. Changes in the refractive index of the medium of less than 0.04, corresponding to a change in surface plasmon resonance of 8 nm, could be readily measured and over longer periods. We used this enhanced spectral sensitivity to measure the presence of neutravidin, exploring the potential of TPL spectroscopy of single GNRs for enhanced plasmonic sensing.

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Tariq, Sara M., Makram A. Fakhri, and Uda Hashim. "Fiber Optics for Sensing Applications in a Review." Key Engineering Materials 911 (February 24, 2022): 65–76. http://dx.doi.org/10.4028/p-k239ba.

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This paper introduces a review of the use of gold nanoparticles (AuNPs) in the fabrication of optical fiber biosensors based on localized surface Plasmon resonance (LSPR) and Evanescent field absorption. The AuNPs have special properties, such as high surface/volume ratio, and intense light scattering/absorption, and stable structure. The main advantage of AuNPs in the application of the biosensor in the detection signal increasing, for especially low concentration analyses. Moreover, we illustrate some of the previous works in this field in the period from 2001-2021, which used optical fiber and AuNPs as a base in the development of various biosensors and all exhibited differently limits of detection, sensitivity, and good performances to its target detection.

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Adegoke, Oluwasesan, and Enoch Y. Park. "Bright luminescent optically engineered core/alloyed shell quantum dots: an ultrasensitive signal transducer for dengue virus RNA via localized surface plasmon resonance-induced hairpin hybridization." Journal of Materials Chemistry B 5, no. 16 (2017): 3047–58. http://dx.doi.org/10.1039/c7tb00388a.

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Jeong, Hyeon-Ho, and Seung-Ki Lee. "The Method of Measurement Signal Processing of Biosensor Based on Optical Fiber Using Reflected Localized Surface Plasmon Resonance." Journal of Sensor Science and Technology 20, no. 2 (March 31, 2011): 107–13. http://dx.doi.org/10.5369/jsst.2011.20.2.107.

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Micek, Patrik, Dusan Pudis, Peter Gaso, Jana Durisova, and Daniel Jandura. "Microring Zone Structure for Near-Field Probes." Coatings 11, no. 11 (November 5, 2021): 1363. http://dx.doi.org/10.3390/coatings11111363.

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Recent advances in Surface Plasmon Resonance (SPR) technologies have shown the possibility of transmission enhancement of localized modes propagating through sub-diffraction wide slits and apertures, resulting in the strong near-field focusing of metallic planar nanostructures. This work presents a new approach to the fabrication of high-resolution near-field optical probes using 3D lithography in combination with numerical finite difference time domain (FDTD) simulations. A narrow 500 nm depth of field focus area was observed both by numerical analysis and near field scanning optical microscopy (NSOM) measurements. Further research and optimization are planned in order to achieve subwavelength focal regions and increased signal intensities.

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Barrios, Carlos Angulo, Teona Mirea, and Miguel Huerga Represa. "A Self-Referenced Refractive Index Sensor Based on Gold Nanoislands." Sensors 23, no. 1 (December 21, 2022): 66. http://dx.doi.org/10.3390/s23010066.

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We report on a self-referenced refractive index optical sensor based on Au nanoislands. The device consists of a random distribution of Au nanoislands formed by dewetting on a planar SiO2/metal Fabry–Pérot cavity. Experimental and theoretical studies of the reflectance of this configuration reveal that its spectral response results from a combination of two resonances: a localized surface plasmon resonance (LSPR) associated to the Au nanoislands and the lowest-order anti-symmetric resonance of the Fabry–Pérot cavity. When the device is immersed in different fluids, the LSPR contribution provides high sensitivity to refractive index variations of the fluid, whereas those refractive index changes have little impact on the Fabry–Pérot resonance wavelength, allowing its use as a reference signal. The self-referenced sensor exhibits a spectral sensitivity of 212 nm/RIU (RIU: refractive index unit), which is larger than those of similar structures, and an intensity sensitivity of 4.9 RIU−1. The proposed chip-based architecture and the low cost and simplicity of the Au nanoisland synthesis procedure make the demonstrated sensor a promising self-referenced plasmonic sensor for compact biosensing optical platforms based on reflection mode operation.

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Chen, Chien-Hsing, and Chang-Yue Chiang. "Determination of the Highly Sensitive Carboxyl-Graphene Oxide-Based Planar Optical Waveguide Localized Surface Plasmon Resonance Biosensor." Nanomaterials 12, no. 13 (June 22, 2022): 2146. http://dx.doi.org/10.3390/nano12132146.

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This study develops a highly sensitive and low-cost carboxyl-graphene-oxide-based planar optical waveguide localized surface plasmon resonance biosensor (GO-OW LSPR biosensor), a system based on measuring light intensity changes. The structure of the sensing chip comprises an optical waveguide (OW)-slide glass and microfluidic-poly (methyl methacrylate) (PMMA) substrate, and the OW-slide glass surface-modified gold nanoparticle (AuNP) combined with graphene oxide (GO). As the GO has an abundant carboxyl group (–COOH), the number of capture molecules can be increased. The refractive index sensing system uses silver-coated reflective film to compare the refractive index sensitivity of the GO-OW LSPR biosensor to increase the refractive index sensitivity. The result shows that the signal variation of the system with the silver-coated reflective film is 1.57 times that of the system without the silver-coated reflective film. The refractive index sensitivity is 5.48 RIU−1 and the sensor resolution is 2.52 ± 0.23 × 10−6 RIU. The biochemical sensing experiment performs immunoglobulin G (IgG) and streptavidin detection. The limits of detection of the sensor for IgG and streptavidin are calculated to be 23.41 ± 1.54 pg/mL and 5.18 ± 0.50 pg/mL, respectively. The coefficient of variation (CV) of the repeatability experiment (sample numbers = 3) is smaller than 10.6%. In addition, the affinity constants of the sensor for anti-IgG/IgG and biotin/streptavidin are estimated to be 1.06 × 107 M−1 and 7.30 × 109 M−1, respectively. The result shows that the GO-OW LSPR biosensor has good repeatability and very low detection sensitivity. It can be used for detecting low concentrations or small biomolecules in the future.

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Adegoke, Oluwasesan, Masahiro Morita, Tatsuya Kato, Masahito Ito, Tetsuro Suzuki, and Enoch Y. Park. "Localized surface plasmon resonance-mediated fluorescence signals in plasmonic nanoparticle-quantum dot hybrids for ultrasensitive Zika virus RNA detection via hairpin hybridization assays." Biosensors and Bioelectronics 94 (August 2017): 513–22. http://dx.doi.org/10.1016/j.bios.2017.03.046.

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Raj, Deepti, Federico Scaglione, and Paola Rizzi. "Rapid Fabrication of Fe and Pd Thin Films as SERS-Active Substrates via Dynamic Hydrogen Bubble Template Method." Nanomaterials 13, no. 1 (December 27, 2022): 135. http://dx.doi.org/10.3390/nano13010135.

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Fe and Pd thin film samples have been fabricated in a rapid fashion utilizing the versatile technique of dynamic hydrogen bubble template (DHBT) method via potentiostatic electrodeposition over a copper substrate. The morphology of the samples is dendritic, with the composition being directly proportional to the deposition time. All the samples have been tested as SERS substrates for the detection of Rhodamine 6G (R6G) dye. The samples perform very well, with the best performance shown by the Pd samples. The lowest detectable R6G concentration was found to be 10−6 M (479 μgL−1) by one of the Pd samples with the deposition time of 180 s. The highest enhancement of signals noticed in this sample can be attributed to its morphology, which is more nanostructured compared to other samples, which is extremely conducive to the phenomenon of localized surface plasmon resonance (LSPR). Overall, these samples are cheaper, easy to prepare with a rapid fabrication method, and show appreciable SERS performance.

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Lin, Shusen, Rutuja Mandavkar, Shalmali Burse, Md Ahasan Habib, Tasmia Khalid, Mehedi Hasan Joni, Young-Uk Chung, Sundar Kunwar, and Jihoon Lee. "MoS2 Nanoplatelets on Hybrid Core-Shell (HyCoS) AuPd NPs for Hybrid SERS Platform for Detection of R6G." Nanomaterials 13, no. 4 (February 18, 2023): 769. http://dx.doi.org/10.3390/nano13040769.

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In this work, a novel hybrid SERS platform incorporating hybrid core-shell (HyCoS) AuPd nanoparticles (NPs) and MoS2 nanoplatelets has been successfully demonstrated for strong surface-enhanced Raman spectroscopy (SERS) enhancement of Rhodamine 6G (R6G). A significantly improved SERS signal of R6G is observed on the hybrid SERS platform by adapting both electromagnetic mechanism (EM) and chemical mechanism (CM) in a single platform. The EM enhancement originates from the unique plasmonic HyCoS AuPd NP template fabricated by the modified droplet epitaxy, which exhibits strong plasmon excitation of hotspots at the nanogaps of metallic NPs and abundant generation of electric fields by localized surface plasmon resonance (LSPR). Superior LSPR results from the coupling of distinctive AuPd core-shell NP and high-density background Au NPs. The CM enhancement is associated with the charge transfer from the MoS2 nanoplatelets to the R6G. The direct contact via mixing approach with optimal mixing ratio can effectively facilitate the charges transfer to the HOMO and LUMO of R6G, leading to the orders of Raman signal amplification. The enhancement factor (EF) for the proposed hybrid platform reaches ~1010 for R6G on the hybrid SERS platform.

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Kim, Hyeong-Min, Se-Woong Bae, Jae-Hyoung Park, and Seung-Ki Lee. "Detection limit enhancement of fiber optic localized surface plasmon resonance biosensor by increased scattering efficiency and reduced background signal." Colloids and Surfaces A: Physicochemical and Engineering Aspects 629 (November 2021): 127439. http://dx.doi.org/10.1016/j.colsurfa.2021.127439.

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Kim, Yelim, Ahmed Salim, and Sungjoon Lim. "Millimeter-Wave-Based Spoof Localized Surface Plasmonic Resonator for Sensing Glucose Concentration." Biosensors 11, no. 10 (September 28, 2021): 358. http://dx.doi.org/10.3390/bios11100358.

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Glucose-monitoring sensors are necessary and have been extensively studied to prevent and control health problems caused by diabetes. Spoof localized surface plasmon (LSP) resonance sensors have been investigated for chemical sensing and biosensing. A spoof LSP has similar characteristics to an LSP in the microwave or terahertz frequency range but with certain advantages, such as a high-quality factor and improved sensitivity. In general, microwave spoof LSP resonator-based glucose sensors have been studied. In this study, a millimeter-wave-based spoof surface plasmonic resonator sensor is designed to measure glucose concentrations. The millimeter-wave-based sensor has a smaller chip size and higher sensitivity than microwave-frequency sensors. Therefore, the microfluidic channel was designed to be reusable and able to operate with a small sample volume. For alignment, a polydimethylsiloxane channel was simultaneously fabricated using a multilayer bonding film to attach the upper side of the pattern, which is concentrated in the electromagnetic field. This real-time sensor detects the glucose concentration via changes in the S11 parameter and operates at 28 GHz with an average sensitivity of 0.015669 dB/(mg/dL) within the 0–300 mg/dL range. The minimum detectable concentration and the distinguishable signal are 1 mg/dL and 0.015669 dB, respectively, from a 3.4 μL sample. The reusability and reproducibility were assessed through replicates.

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Nasrin, Fahmida, Ankan Dutta Chowdhury, Kenshin Takemura, Jaewook Lee, Oluwasesan Adegoke, Vipin Kumar Deo, Fuyuki Abe, Tetsuro Suzuki, and Enoch Y. Park. "Single-step detection of norovirus tuning localized surface plasmon resonance-induced optical signal between gold nanoparticles and quantum dots." Biosensors and Bioelectronics 122 (December 2018): 16–24. http://dx.doi.org/10.1016/j.bios.2018.09.024.

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Khosroshahi, Mohammad E., Vaughan W. Morison, Roxana Chabok, Yesha Patel, and Tiam Mohmedi. "Observation and biomedical application of plasmon-enhanced fluorescence induced multiple stimulated Stokes Raman scattering in FITC-conjugated gold nanoparticles solution." Laser Physics 32, no. 10 (October 1, 2022): 105601. http://dx.doi.org/10.1088/1555-6611/ac9373.

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Abstract This work describes the observation of multi-wavelengths due to stimulated Raman scattering from deep red to near-infrared (NIR) induced by plasmon-enhanced fluorescence (PEF) of fluorescein isothiocyanate (FITC) conjugated gold nanoparticles (F-AuNP) excited by 488 nm diode laser. Coupling between the near-field of localized surface plasmons of AuNP with molecules amplifies the fluorescence signal i.e. brightness hence the quantum yield by several orders of magnitude. Resonance Rayleigh scattering and PEF conditions are satisfied due to the overlapping of 488 nm of the laser beam with the maximum absorbance of FITC, and the SPR of AuNP with FITC emission spectrum at ≈525 nm. PEF acts as Stoke sand secondary pump beam for further optical excitation. Surface-enhanced Raman scattering (SERS) showed FITC molecular bonds at 600, 1680, and a weak deviation at 1280 cm−1, respectively. Longer wavelengths with higher output power were observed between 180° and 270°, and shorter wavelengths with lower power between 90° and 0° respectively. F-AuNPs were incubated and up taken by the oyster mushroom (OM) grown in the lab for bioimaging purposes and studied by phase-contrast microscope (PCM), and fluorescence microscope (FM). The FM results revealed visible colours, which can be utilized for in vitro and in vivo biosensing applications.

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Journal articles on the topic 'Localized Surface Plasmon Resonance signals'

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