Silver-Based Surface Plasmon Sensors: Fabrication and Applications

Abstract

A series of novel phenomena such as optical nonlinear enhancement effect, transmission enhancement, orientation effect, high sensitivity to refractive index, negative refraction and dynamic regulation of low threshold can be generated by the control of surface plasmon (SP) with metal micro-nano structure and metal/material composite structure. The application of SP in nano-photonics, super-resolution imaging, energy, sensor detection, life science, and other fields shows an important prospect. Silver nanoparticles are one of the commonly used metal materials for SP because of their high sensitivity to refractive index change, convenient synthesis, and high controllable degree of shape and size. In this review, the basic concept, fabrication, and applications of silver-based surface plasmon sensors are summarized.

Keywords: SERS; SPR; silver nanoparticles; surface plasmon.

Figure 1

(a) interaction of a light wave with a spherical metallic NP causing oscillation of the electron cloud on the surface of the NP. (b) Extinction spectra of the Ag NPs fabricated from the different initial Ag deposition thickness. The main peak position of the extinction was indicated by the arrow. Reprinted with permission from Ref. [22]. Copyright 2021, Vacuum. (c) Absorbance spectra of the Ag NP of 5 nm (solid black line), 10 nm (solid red line), 20 nm (solid blue line), 50 nm (solid green line), 100 nm (solid magenta line), and 200 nm (solid olive line). Reprinted with permission from Ref. [23]. Copyright 2016, Optical Materials. (d) Absorption spectra for the corresponding morphologies that can be generated with the LED irradiation approach from a single precursor solution of 3 nm silver seeds. Reprinted with permission from Ref. [24]. Copyright 2012, Photochemistry and photobiology. (e) near-field intensity distribution around a single silver nanoparticle. Reprinted with permission from Ref. [25]. Copyright 2016, Advances in Physics. (f) Electromagnetic (EM) enhancement mechanism in SERS, including the two-step enhancements, illustrated in the nanogap of two metal nanoparticles. Reprinted with permission from Ref. [31]. Copyright 2018, Chemical Reviews. (g) Chemical enhancement through charge transfer (CT) between metal/semiconductor and the adsorbed molecule. The CT transitions (μCT) arrows show the CT directions. Red and white circles represent molecular orbitals. CB, conduction band; EF, Fermi level; HOMO, highest occupied molecular orbital; LUMO, lowest unoccupied molecular orbital; VB, valence band. Reprinted with permission from Ref. [31]. Copyright 2018, Chemical Reviews.

Figure 4

(a) TEM images of biosynthesized AgNPs from Rhodococcus (i), Bacillus (ii), and Brevundimonas (iii). Reprinted with permission from Ref. [79]. Copyright 2022, Marine Drugs. (b) TEM micrograph: scale bar 50 nm. Reprinted with permission from Ref. [81]. Copyright 2017, Materials Science and Engineering: C. (c) The antimicrobial effects of biosynthesized AgNPs evaluated by the standard Kirby-Bauer disc diffusion method on MHA plates. Reprinted with permission from Ref. [81]. Copyright 2017, Materials Science and Engineering: C. (d) Characterization of Ag-NPs formed by biomass filtrate of A. niger strain F2. TEM image and size distributions based on the TEM image. Reprinted with permission from Ref. [82]. Copyright 2022, In Journal of Fungi. (e) Schematic illustration of the formation of silver nanoparticles mediated by nucleotide-based assemblies. Reprinted with permission from Ref. [86]. Copyright 2018, ACS Applied Materials and Interfaces.

Figure 5

(a) Schematic illustration of the synthesis process of Ag NSs using a seed-mediated growth coupled with a chemical etching method. Reprinted with permission from Ref. [90]. Copyright 2018, Langmuir. (b) TEM image of Au@Ag nanocubes. Reprinted with permission from Ref. [93]. Copyright 2008, Journal of the American Chemical Society. (c) Schematic representation of the growth of Ag NPs on Au seeds. Reprinted with permission from Ref. [96]. Copyright 2022, Vibrational Spectroscopy. (d) substrate with 1st growth cycle. Reprinted with permission from Ref. [96]. Copyright 2022, Vibrational Spectroscopy. (e) SEM image of the substrate after the 4th growth cycle. Reprinted with permission from Ref. [96]. Copyright 2022, Vibrational Spectroscopy.

Figure 6

(a) Schematic representation for the syntheses of Ag NPs, where the solvent is a. pure glycerol and b. glycerol/water mixtures. MW: microwave. Reprinted with permission from Ref. [101]. Copyright 2021, International Journal of Hydrogen Energy. (b) Aging of Ag NPs. Reprinted with permission from Ref. [101]. Copyright 2021, International Journal of Hydrogen Energy. (c) TEM image of a typical individual silver nanostar. (d) TEM image of the central zone of the nanostar. Reprinted with permission from Ref. [102]. Copyright 2022, International Journal of Molecular Sciences. (e) Yields as a function of time for extractions of essential oil from rosemary leaves by microwave hydro-diffusion and gravity (MHG) (●) and hydro-distillation (○). Reprinted with permission from Ref. [103]. Copyright 2013, TrAC Trends in Analytical Chemistry. (f) Glucose yields of enzymatic hydrolysis of the cellulose-rich residues obtained from the integrated process. Reprinted with permission from Ref. [105]. Copyright 2022, Energy.

Figure 13

(a) Fabrication processes of the shared substrate. Reprinted with permission from Ref. [138]. Copyright 2021, Small. (b) SEM images and EDX spectroscopy of Ag-AuNDs substrate. SERS spectra of thiram with a concentration of 0–5 mg/L and 0–24 mg/L. Reprinted with permission from Ref. [144]. Copyright 2021, Food Control. (c) In-situ SERS detections of hazardous residues on fish by a ‘paste-test’ method. Raman spectra of thiram and TBZ detected on pears. Raman spectra of MG an ENRO detected on fishes. Reprinted with permission from Ref. [145]. Copyright 2021, Applied Surface Science. (d) Schematic of preparation process of superhydrophobic Ag-coated cotton fabric substrate and SERS evaluation of prepared substrates. Changes in Raman spectra of MB with time on the same area of AC100 plotted at 1 min intervals for 10 min, and intensity of peaks of Raman signals. Reprinted with permission from Ref. [147]. Copyright 2020, Applied Surface Science.

Figure 2

Top-down and bottom-up approach for fabricating Ag NPs. Major synthetic approaches for the fabrication of Ag NPs. TEM images of silver nanoparticles with different shapes: (A) nanospheres Reprinted with permission from Ref. [41]. Copyright 2004, Nano Letters. (B) nanoprisms Reprinted with permission from Ref. [42]. Copyright 2012, Colloids and Surfaces A. (C) nanobars Reprinted with permission from Ref. [43]. Copyright 2007, Nano Letters. (D) nanowires Reprinted with permission from Ref. [44]. Copyright 2002, Advanced Materials. SEM images of (E) nanocubes, (F) pyramids Reprinted with permission from Ref. [45]. Copyright 2006, The Journal of Physical Chemistry B. (G) nanorice Reprinted with permission from Ref. [43]. Copyright 2007, Nano Letters. and (H) nanoflowers Reprinted with permission from Ref. [46]. Copyright 2011, Materials Research Bulletin.

Figure 3

(a) A stepwise reduction method, in which the nucleation and growth processes were carried out at high and low pH, respectively, was proposed for the syntheses of spherical silver nanoparticles. Reprinted with permission from Ref. [65]. Copyright 2009, The Journal of Physical Chemistry C. (b) Optimization of silver nanoparticle synthesis by chemical reduction and evaluation of its antimicrobial and toxic activity. Reprinted with permission from Ref. [67]. Copyright 2019, Biomaterials research. Copyright 2019, Biomater Research. (c) Reduction of Ag⁺ ions by EG leads to the formation of nuclei. The structure of nuclei fluctuates depending on their size and the thermal energy available. Reprinted with permission from Ref. [70]. Copyright 2007, Accounts of Chemical Research.

Figure 7

SEM micrographs of (a) GO and (b) GO-Ag nanocomposite and (c) EDX of GO-Ag nanocomposite. TEM micrographs of (c) GO and (d) GO-Ag nanocomposite. Reprinted with permission from Ref. [108]. Copyright 2020, ACS Omega. (e) TEM image of Ag-NPs synthesized under ultrasonic irradiation for 45 min (AgNO₃ = 0.1 M, gelatin = 1%, and amplitude = 50). Reprinted with permission from Ref. [109]. Copyright 2012, Materials Letters. (f) Schematic illustration of the synthesis process of cubic AgNPs using sonochemical process. Reprinted with permission from Ref. [111]. Copyright 2022, Surfaces and Interfaces. (g) TEM image of Ag cubic. Reprinted with permission from Ref. [111]. Copyright 2022, Surfaces and Interfaces.

Figure 8

Applications of silver-based plasmon sensing in three fields: food detection, environment monitoring, biomedical sensing.

Figure 9

(a) The microcuvette modulation for spectrophotometric measurements at the solid platform for the same enantiomeric percentage range of D-cysteine. Reprinted with permission from Ref. [119]. Copyright 2018, Talanta (Oxford). (b) The recorded UV-Vis spectra for the corresponding microcuvettes. Reprinted with permission from Ref. [119]. Copyright 2018, Talanta (Oxford).

Figure 10

(a) Schematic of synthesis of functionalized CNTs and ZnO nanoparticles, attachment of ZnO nanoparticles to CNTs walls, CTAB functionalization of ZnO/CNTs nanocomposite for two concentrations, fiber probe, and experimental set-up. Results of repeatability and selectivity for the finalized. Reprinted with permission from Ref. [122]. Copyright 2020, ACS Applied Nano Materials. (b) Schematic illustration of sensing of Hg²⁺ by AV-AgNPs. UV-vis spectra recorded upon 1 mL addition of AV-AgNPs with different metal ion solutions (500 μM, 2 mL). Reprinted with permission from Ref. [123]. Copyright 2022, Journal of Molecular Liquids. (c) SPR band changes of Cys-AgNPs with different amounts of S²⁻ ion and inset shows photographic image of (i) Cys-AgNPs in the (ii) final addition S²⁻ ions. Relative absorption intensities and the colorimetric response of Cys-AgNPs towards S²⁻ ions as well 100-fold higher concentrations of different interfering inorganic anions and few cations. Reprinted with permission from Ref. [124]. Copyright 2022, Microchemical Journal. Copyright 2022, Microchemical Journal.

Figure 11

(a) Schematic of bio-sensing approaches using the Ag NPs-based LSPR sensor probe. Reprinted with permission from Ref. [127]. Copyright 2015, Sensors. (b) LSPR peak wavelength changes during the process of anti-human IgG immobilization on the Ag NP-based sensor surface over a period of 35 min. Reprinted with permission from Ref. [127]. Copyright 2015, Sensors. (c) Schematic of the biosensor used with on-chip separation and detection of NS1. Reprinted with permission from Ref. [128]. Copyright 2019, Biosensors and Bioelectronics. (d) Construction of HCR-based specific DNA detection platform. The sensing mechanism is based on the etching process of triangular silver nanoprisms. Reprinted with permission from Ref. [129]. Copyright 2014, ACS Nano. (e) Specificity of the DNA detection. UV-vis spectra of triangular silver nanoprisms in the presence of target DNA (10 nM) with different mismatched bases. Reprinted with permission from Ref. [129]. Copyright 2014, ACS Nano.

Figure 12

Two different composite modes (a) Experimental schematic of the shared substrate. Reprinted with permission from Ref. [138]. Copyright 2021, Small. (b) Schematic of the Ag@ZnO chip. Reprinted with permission from Ref. [139]. Copyright 2021, RSC Advances. (c) Schematic diagram of silver nanowires array. Reprinted with permission from Ref. [140]. Copyright 2022, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. (d) Schematic of MoS₂/AgNPs. Reprinted with permission from Ref. [141]. Copyright 2016, Applied Surface Science. (e) schematic of Fe₃O₄@MIL-100(Fe)@Ag NPs. Reprinted with permission from Ref. [142]. Copyright 2022, Microchemical Journal. (f) Schematic Diagram of Experimental Procedure for SERS Detection of Proteins Using Ag IANPs as Substrates. Reprinted with permission from Ref. [143]. Copyright 2020, Analytical chemistry.

Figure 14

(a) Fabrication of the TiO₂ NTs/AgNPs-rGO hybrid SERS substrate. Reprinted with permission from Ref. [150]. Copyright 2022, Journal of Hazardous Materials. (b) Raman spectra of glyphosate with different concentrations on the TiO₂ NTs/AgNPs-rGO substrate. Reprinted with permission from Ref. [150]. Copyright 2022, Journal of Hazardous Materials. (c) Corresponding calibration curve obtained at the characteristic peak of 920 cm⁻¹. Reprinted with permission from Ref. [150]. Copyright 2022, Journal of Hazardous Materials. (d) Illustration of HOX@Ag-PVDF capturing Cu²⁺. Reprinted with permission from Ref. [151]. Copyright 2022, Journal of Hazardous Materials. (e) SEM image of HOX@Ag-PVDF with Cu²⁺. Reprinted with permission from Ref. [151]. Copyright 2022, Journal of Hazardous Materials. (f) Capture mechanism of HOX@Ag-PVDF for Cu²⁺. Reprinted with permission from Ref. [151]. Copyright 2022, Journal of Hazardous Materials.

Figure 15

(a) Schematic of the Ag@ZnO chip and its fabrication process. The signal intensity versus oxycodone concentrations at the characteristic peaks at 1360 cm⁻¹ and 1590 cm⁻¹. Reprinted with permission from Ref. [139]. Copyright 2021, RSC Adv. (b) Schematic of the synthesis of AgNPs-4MPBA and the process of fructose-induced deboronation reaction. SERS spectra of AgNPs-4MPBA substrate and fructose in urine with concentrations: 0, 0.5, 1, 5, 50, 100 μmol/L, Working curve of fructose concentration and SERS peak intensity at 1570 cm⁻¹ in urine. Reprinted with permission from Ref. [153]. Copyright 2023, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. (c) Schematic illustrations of the sandwich-structured sensing system for SERS/electrochemical (EC) dual-mode detection of miR-106a. Reprinted with permission from Ref. [154]. Copyright 2022, Sensors and Actuators B: Chemical.

Figure 16

(a) Schematic fabrication process of Ag@IP6@AuNPs substrate and the SERS detection of PG. Concentration-dependent SERS spectra of Penicillin G by using Ag@IP6@AuNPs. Reprinted with permission from Ref. [160]. Copyright 2021, Sensors and Actuators B: Chemical. (b) SERS spectra of a. lysozyme, b. α-casein, c. insulin, d. myoglobin, e. catalase, and f. BSA at concentrations of 30 μg/mL using Ag IANPs. Reprinted with permission from Ref. [143]. Copyright 2020, Analytical chemistry. (c) Correlation curve of I752/I1004 versus Trp/(Trp + Phe). Reprinted with permission from Ref. [143]. Copyright 2020, Analytical chemistry. (d) The number of Trp and Phe in six proteins. I752 and I1004 represent the intensity at 752 and 1004 cm⁻¹, respectively, and Trp/(Trp + Phe) is the ratio of the number of Trp to the number of Trp + Phe. Reprinted with permission from Ref. [143]. Copyright 2020, Analytical chemistry.