SERS Sensors: Recent Developments and a Generalized Classification Scheme Based on the Signal Origin

Figure 1: (a) At top is an electrified interface in which the electrode is negatively charged; countercations are aligned along the electrified surface. At bottom are the electrical circuit elements c...

Figure 2: Nyquist plots obtained from Equation 7 with different kinetic parameters. The calculations were performed between 50 kHz and 1 Hz. The values (relative rates of electron transfer to that of...

Figure 3: Ratio of the time constants plotted for the ratio of R values obtained from the parallel connection of Rp and Rs (τ(Rs‖Rp)·Cd) to the ratio calculated with Rs alone (τRs·Cd). Data taken from...

Figure 4: (a) General scheme for label-free detection via electrochemical impedance spectroscopy (EIS). The charge-transfer impedance for the probe ions (P) is increased due to the target analyte boun...

Figure 5: Impedance imaging of two-dimensional surfaces via scanning probes. (a) Scheme for impedance imaging of a cone-shaped pore in the polycarbonate membrane by scanning electrochemical microscopy...

Figure 1: (a) Illustration of the localized surface plasmon resonance effect. (b) Extinction efficiency (ratio of cross section to effective area) of a spherical silver nanoparticle of 35-nm radius in...

Figure 2: (a) Surface-enhanced Raman spectra of pyridine adsorbed to silver film over nanosphere samples treated with various thicknesses of alumina (0.0 nm, 1.6 nm, 3.2 nm, and 4.8 nm). ex = 532 nm, ...

Figure 3: (a) Surface-enhanced Raman excitation spectra with Si as intensity standard. Localized surface plasmon resonance (LSPR) λmax = 690 nm, profile fit maximum at λex, max = 662 nm. (b–d) Effect ...

Figure 4: Schematic diagram of typical instrumentation used for surface-enhanced Raman spectroscopy experiments. (a) Macro-Raman configuration used when 100-μm-to-millimeter spatial resolution is suff...

Figure 5: Schematic representation of the nanosphere lithography process for fabricating metal film over nanosphere and periodic particle arrays of metal nanotriangles.

Figure 6: Glucose reversibility and partial least-squares leave-one-out analysis. Glucose pulsing sequence on the self-assembled monolayer–modified Ag film over nanosphere (AgFON) surface for reversib...

Figure 7: Sequential glucose and lactate pulsing. (a) Step changes of glucose (G) and lactate (L) concentrations (0–100 mM) introduced into the sensor. (b) Mean difference spectrum (average of differe...

Figure 8: Stability of Ag film over nanosphere (AgFON) toward replicate adsorption-desorption cycles of benzene and pyridine. (a) Surface-enhanced Raman spectroscopy (SERS) intensity of the 992 cm−1 p...

Figure 9: Surface-enhanced Raman spectroscopy (SERS) detected cyclic voltammograms. SERS intensity of the 1008 cm−1 band of pyridine (ring breathing mode) versus potential. (a) Ag film over nanosphere...

Figure 1: The mass parabolas of the Ne isotopes 20 and 22 (lower right) of ∼10:1 relative abundance. Reprinted from Reference 6 (plate I) with permission.

Figure 2: Electron ionization mass spectrum of benzene showing galvanometer measurements of ion currents as a function of magnetic field (7). Note the unit mass resolution between the C6H6+· and C6H5+...

Figure 3: Time-of-flight mass spectra recorded from an oscilloscope on Polaroid film of eluted gas chromatography fractions. (a) Acetone (m/z 14–58). (b) Benzene (m/z 36–79). (c) Toluene (m/z 27–92). ...

Figure 4: A four-sector EBEB mass spectrometer (85), constructed between 1977 and 1980, that was used for high-resolution tandem mass spectrometry (MS/MS) and MS/MS/MS (EB/E/B) of larger molecules and...

Figure 5: Backbone cleavages indicated by fragment ions in a single plasma electron-capture dissociation (ECD) spectrum (117) of bovine carbonic anhydrase (259 residues; molecular weight: calculated, ...

Figure 6: Stepwise evolution, after electrospray ionization, of the structure of a native or denatured protein such as cytochrome c or ubiquitin. On entry into the mass spectrometric vacuum system, (a...

Figure 1: Fluidic features produced by 3D printing. (a) Gradient mixing device consisting of several intersecting turbulent mixing sections used to measure nitrite concentrations. Adapted with permiss...

Figure 2: Template and surface of 3D printed microfluidic devices. (a,b) Images showing the surface roughness of a polylactic acid fused deposition modeling (FDM) template before and after smoothing w...

Figure 3: Stereolithography (SLA) 3D printed microfluidic devices with ∼50-μm features. (a) Chain links of varying sizes as small as 4 μm. Adapted with permission from Reference 90. (b) Microfluidic b...

Figure 4: New approaches for 3D printing of microfluidic devices and structures. (a) Two-photon polymerization of a spring diode inside a microfluidic channel. Adapted with permission from Reference 1...

Figure 1: Sanger sequencing.

Figure 2: Comparison between (a) paired-end and (b) mate-pair sequencing library-construction processes.

Figure 3: (a) Illumina® library-construction process. (b) Illumina cluster generation by bridge amplification. (c) Sequencing by synthesis with reversible dye terminators.

Figure 4: (a) Structure of the Ion Torrent Ion Chip used in pH-based sequencing. (b) pH sensing of nucleotide incorporation.

Figure 5: Single-molecule sequencing using Pacific Biosciences' zero-mode waveguides.