Activity

However, glutamine was an exception because the L-isomer had a stronger binding affinity with Fc-(S,S)-1 + Cu(II), which would limit the transport of the complex into the cavity of CBPQT4+-2, thereby resulting in a low peak current. Thus, an inverse phenomenon was observed with glutamine. In summary, we believe that this work can increase the testing scope for the chiral recognition of different kinds of isomers using electrochemical tools.Single particle plasmon scattering can provide real-time imaging information on the synthesis of nanomaterials. Here, an electrochemical deposition strategy is reported to synthesize plasmonic Au@Metal core-shell nanoparticles (Au@M NPs), which exhibit localized surface plasmon resonance (LSPR) properties. Because of the excellent catalytic activity of the methanol oxidation reaction (MOR), Pt, Pd, and Rh were reduced on the surface of Au NPs to form monometallic and bimetallic shells. Under dark field microscopy (DFM), the scattering changes could be utilized to track the surface nucleation and bulk deposition process. The synthesized Au@M NPs, which combined the plasmonic and electrocatalytic features, showed greatly enhanced activity for MOR. Under LSPR excitation, the electroxidation process toward MOR was accelerated and increased approximately linearly with increased illumination intensity, which could be mostly attributed to the generation of energetic charge carriers. This strategy of real-time plasmonic tracking electrochemical deposition at the single particle level is facile and universal, which could be extended to the precise synthesis of other plasmonic core-shell nanomaterials and the investigation of the pathway of plasmon accelerated chemical conversion.A novel biosensing system based on graphene-mediated surface-enhanced Raman scattering (G-SERS) using plasmonic/magnetic molybdenum trioxide nanocubes (mag-MoO3 NCs) has been designed to detect norovirus (NoV) via a dual SERS nanotag/substrate platform. A novel magnetic derivative of MoO3 NCs served as the SERS nanotag and the immunomagnetic separation material of the biosensor. Single-layer graphene oxide (SLGO) was adopted as the 2D SERS substrate/capture platform and acted as the signal reporter, with the ability to accommodate an additional Raman molecule as a coreporter. The developed SERS-based immunoassay achieved a signal amplification of up to ∼109-fold resulting from the combined electromagnetic and chemical mechanisms of the dual SERS nanotag/substrate system. The developed biosensor was employed for the detection of NoV in human fecal samples collected from infected patients by capturing the virus with the aid of NoV-specific antibody-functionalized magnetic MoO3 NCs. This approach enabled rapid signal amplification for NoV detection with this biosensing technology. The biosensor was tested and optimized using NoV-like particles within a broad linear range from 10 fg/mL to 100 ng/mL and a limit of detection (LOD) of ∼5.2 fg/mL. The practical applicability of the developed biosensor to detect clinical NoV subtypes in human fecal samples was demonstrated by effective detection with an LOD of ∼60 RNA copies/mL, which is ∼103-fold lower than that of a commercial enzyme-linked immunosorbent assay kit for NoV.Real-time and in situ detection of aqueous solution is essential for bioanalysis and chemical reactions. However, it is extremely challenging for infrared microscopic measurement because of the large background of water absorption. Here, we proposed a wideband-tunable graphene plasmonic infrared biosensor to detect biomolecules in an aqueous environment, employing attenuated total reflection in an Otto prism configuration and tightly confined plasmons in graphene nanoribbons. Benefiting from the graphene plasmonic electric field enhancement, such a biosensor is able to identify the molecular chemical fingerprints without the interference of water absorption. As a proof of concept, the recombinant protein AG and goat anti-mouse immunoglobulin G (IgG) are used as the sensing analytes, of which the vibrational modes (1669 and 1532 cm-1) are very close to the OH-bending mode of water (1640 cm-1). Fluzoparib Simulation results show that the fingerprints of protein molecules in the water environment can be selectively enhanced. Therefore, the water absorption is successfully suppressed so that two protein modes can be resolved by sweeping graphene Fermi energy in a wide waveband. By further optimizing the incident angle and graphene mobility to improve the mode energy of graphene plasmons, maximum enhancement factors of 112 and 130 can be achieved for amide I and II bands. Our work provides an effective approach for the highly sensitive and selective in situ identification of aqueous-phase molecular fingerprints in fields of healthcare, food safety, and biochemical sensing.A new theoretical model is formulated for the quantitative analysis of quartz crystal microbalance (QCM) response for heterogeneous loads consisting of nano- and microparticles. The influence of particle coverage and structure is described using a universal correction function in an ab initio manner. Explicit analytical expressions for the frequency and dissipation shifts are derived for the entire range of particle size under the rigid contact regime. The solvent coupling functions are also calculated to determine the dry coverage using the QCM measurements. These expressions furnish the upper limit of the QCM signal, which can be attained for a sensor providing perfect adhesion of particles. Correction functions accounting for the finite adhesion strength (soft contact regime) are also derived. The theoretical results are confronted with QCM and atomic force microscopy measurements of positively charged polymer particle deposition on silica sensors. The main features of the theoretical model are confirmed, especially the abrupt decrease in the QCM wet mass with the particle coverage and the overtone number. The latter effect is especially pronounced for microparticles under the soft contact regime, where the higher-number overtones produce a negligible QCM signal. These results represent a useful reference data for the interpretation of protein and bioparticles, for example, virus and bacteria attachment processes to various substrates.