Multicellular systems, such as microbial biofilms and cancerous tumors, feature complex biological activities coordinated by cellular interactions mediated via different signaling and regulatory ...pathways, which are intrinsically heterogeneous, dynamic, and adaptive. However, due to their invasiveness or their inability to interface with native cellular networks, standard bioanalysis methods do not allow in situ spatiotemporal biochemical monitoring of multicellular systems to capture holistic spatiotemporal pictures of systems‐level biology. Here, a high‐throughput reverse nanoimprint lithography approach is reported to create biomimetic transparent nanoplasmonic microporous mesh (BTNMM) devices with ultrathin flexible microporous structures for spatiotemporal multimodal surface‐enhanced Raman spectroscopy (SERS) measurements at the bio‐interface. It is demonstrated that BTNMMs, supporting uniform and ultrasensitive SERS hotspots, can simultaneously enable spatiotemporal multimodal SERS measurements for targeted pH sensing and non‐targeted molecular detection to resolve the diffusion dynamics for pH, adenine, and Rhodamine 6G molecules in agarose gel. Moreover, it is demonstrated that BTNMMs can act as multifunctional bio‐interfaced SERS sensors to conduct in situ spatiotemporal pH mapping and molecular profiling of Escherichia coli biofilms. It is envisioned that the ultrasensitive multimodal SERS capability, transport permeability, and biomechanical compatibility of the BTNMMs can open exciting avenues for bio‐interfaced multifunctional sensing applications both in vitro and in vivo.
A high‐throughput reverse nanoimprint lithography approach is reported to create biomimetic transparent nanoplasmonic microporous mesh (BTNMM) devices for spatiotemporal multimodal surface‐enhanced Raman spectroscopy (SERS) measurements at the bio‐interface. It is demonstrated that the BTNMMs, supporting uniform and ultrasensitive SERS hotspots, can serve as multifunctional bio‐interfaced mesh SERS sensors to conduct in situ spatiotemporal pH mapping and molecular profiling of Escherichia coli biofilms.
The particles of the solid solution of strontium molybdate and tungstate (SrMo.sub.0.5W.sub.0.5O.sub.4) were doped with Eu.sup.3+ ions at concentrations of 1, 2 and 4 mol% synthesized by the ...microwave-hydrothermal method (MHM). The structural analyses of the particles were conducted by XRD with Rietveld Refinement and FT-Raman spectroscopy. The crystallization and growth of particles were investigated by FEG-SEM and proposed a mechanism of particle development involving the steps: nucleation and further growth. The SrMo.sub.0.5W.sub.0.5O.sub.4 presented white emission with the chromaticity coordinates: (0.32; 0.40). The Sr.sub.(1-x)Eu.sub.xMo.sub.0.5W.sub.0.5O.sub.4 samples exhibited an increase in luminescence intensity in the red region as the concentration of Eu.sup.3+ increases, a behavior attributed to the .sup.5D.sub.0 right arrow .sup.7F.sub.2 transition of Eu.sup.3+ (623 nm). The Sr.sub.(1-x)Eu.sub.xMo.sub.0.5W.sub.0.5O.sub.4 samples showed high color purity (almost equal to 97%), as well as the results of the color reproduction index (CRI) reached 80% level. The radiation luminous efficiency (LER) presented by the samples exhibited values of 322 lm.W.sup.-1. According to the quality of the photometric parameters presented, the samples have attributions for application in solid-state lighting devices. Graphical abstract
Surface‐enhanced Raman spectroscopy (SERS) has become a sensitive detection technique for biochemical analysis. Despite significant research efforts, most SERS substrates consisting of ...single‐resonant plasmonic nanostructures on the planar surface suffer from limitations of narrowband SERS operation and unoptimized nano‐bio interface with living cells. Here, it is reported that nanolaminate plasmonic nanocavities on 3D vertical nanopillar arrays can support a broadband SERS operation with large enhancement factors (>106) under laser excitations at 532, 633, and 785 nm. The multi‐band Raman mapping measurements show that nanolaminate plasmonic nanocavities on vertical nanopillar arrays exhibit broadband uniform SERS performance with diffraction‐limited resolution at a single nanopillar footprint. By selective exposure of embedded plasmonic hotspots in individual metal–insulator–metal (MIM) nanogaps, nanoscale broadband SERS operation at the single MIM nanocavity level with visible and near‐infrared (vis–NIR) excitations is demonstrated. Numerical studies reveal that nanolaminate plasmonic nanocavities on vertical nanopillars can support multiple hybridized plasmonic modes to concentrate optical fields across a broadband wavelength range from 500 to 900 nm at the nanoscale.
Multiresonant nanolaminate plasmonic nanocavities on vertical nanopillar arrays can support a multi‐band surface‐enhanced Raman spectroscopy operation with large enhancement factors (>106) under 532, 633, and 785 nm laser excitations at the single nanocavity level, which is due to the presence of multiple spectrally separated and spatially overlapped hybrid plasmonic modes in nanolaminate plasmonic nanocavities over a broad vis–NIR range.
Featured Cover Fuini, Evan; Reimers, Alexandra; Hudspeth, Amber ...
Journal of Raman spectroscopy,
April 2022, 2022-04-00, 20220401, Letnik:
53, Številka:
4
Journal Article
Recenzirano
The cover image is based on the Research Article Raman spectroscopy detects adulterated counter‐ions in pharmaceuticals by Evan Fuini et al., https://doi.org/10.1002/jrs.6306.
The domain structure of two selected single-crystal VO.sub.2 microrods (MRs) with different morphologies was mapped by pixelated Raman imaging through the metal-to-insulator transition (MIT) during ...heating and cooling schedules through 68 °C. The results show that MIT does not occur simultaneously and uniformly throughout the whole MR, and instead, it proceeds through alternating metal-insulator domains. Each structural domain possesses its own MIT transition temperature and hysteresis width. The variations in MIT characteristics among different domains of a single MR are probably ascribed to structural nonuniformity. The observed overall MIT transition and hysteresis width of a given VO.sub.2 single-crystal MR is an aggregate manifestation of the MIT properties of domains within the crystal. Graphic abstract
•Detection of explosives is of major concern in very different fields.•FTIR and Raman are powerful techniques for identifying explosives.•Raman spectroscopy allows non-invasive and stand-off ...detection of explosives.•FTIR is useful for the detection of explosives in the environment.•SERS and resonance Raman detect traces of explosives.
This review summarizes the recent trends and developments of infrared and Raman spectroscopy applied to the identification of explosives that have been published over the past decade, focusing on the different fields where explosives were studied: homeland and international security, forensics, environmental, characterization of explosives, trace detection and fluorescence-free Raman analysis of explosives.
The layer-structured monoclinic Lisub.2MnOsub.3 is a key material, mainly due to its role in Li-ion batteries and as a precursor for adsorbent used in lithium recovery from aqueous solutions. In the ...present work, we used first-principles calculations based on density functional theory (DFT) to study the crystal structure, optical phonon frequencies, infra-red (IR), and Raman active modes and compared the results with experimental data. First, Lisub.2MnOsub.3 powder was synthesized by the hydrothermal method and successively characterized by XRD, TEM, FTIR, and Raman spectroscopy. Secondly, by using Local Density Approximation (LDA), we carried out a DFT study of the crystal structure and electronic properties of Lisub.2MnOsub.3. Finally, we calculated the vibrational properties using Density Functional Perturbation Theory (DFPT). Our results show that simulated IR and Raman spectra agree well with the observed phonon structure. Additionally, the IR and Raman theoretical spectra show similar features compared to the experimental ones. This research is useful in investigations involving the physicochemical characterization of Lisub.2MnOsub.3 material.
The MoS.sub.2/Ag/AgBr composite with ultrathin-MoS.sub.2 layers was prepared by the methods of ultrasonic liquid exfoliation and ion exchange. The composition and micromorphology of ...ultrathin-MoS.sub.2/Ag/AgBr were detected by XRD, EDS, SEM and TEM in detail. The element mapping showed that the samples were well-distributed. The MoS.sub.2 in samples and the number of plies were detected by Raman spectra specifically. The results indicated that the photocatalytic performance of the as-prepared samples would increase by 50% when the average thickness of MoS.sub.2 was about 4 nm. The enhanced photocatalytic performance of ultrathin-MoS.sub.2/Ag/AgBr composite is attributed to the modified conduction band of MoS.sub.2 by reducing the layers of MoS.sub.2 to fit the potential of O.sub.2/O2·-. In particular, this work would expand the scope of application of MoS.sub.2 in photodegradation.
Today, BaFBr crystals activated by europium ions are used as detectors that store absorbed energy in metastable centers. In these materials, the image created by X-ray irradiation remains stable in ...the dark for long periods at room temperature. As a result, memory image plates are created, and they are extended to other types of ionizing radiation as well. Despite significant progress towards X-ray storage and readout of information, the mechanisms of these processes have not been fully identified to date, which has hindered the efficiency of this class of phosphors. In this study, using photoluminescence (PL), optical absorption (OA), Raman spectroscopy (RS), and atomic force microscopy (AFM), the luminescence of oxygen vacancy defects to BaFBr crystals irradiated with 147 MeV sup.84Kr and 24.5 MeV sup.14N ions at 300 K to fluences (10sup.10–10sup.14) ion/cmsup.2 was investigated. BaFBr crystals were grown by the Shteber method on a special device. Energy-dispersive X-ray spectroscopy (EDX) analysis revealed the presence of Ba, Br, F, and O. The effect of oxygen impurities present in the studied crystals was considered. The analysis of the complex PL band, depending on the fluence and type of ions, showed the formation of three types of oxygen vacancy defects. Macrodefects (tracks) and aggregates significantly influence the luminescence of oxygen vacancy defects. The creation of hillocks and tracks in BaFBr crystals irradiated with 147 MeV sup.84Kr ions is shown for the first time. Raman spectra analysis confirmed that BaFBr crystals were amorphized by 147 MeV sup.84Kr ions due to track overlap, in contrast to samples irradiated with 24.5 MeV sup.14N ions. Raman and absorption spectra demonstrated the formation of hole and electron aggregate centers upon swift heavy ions irradiation.
Milk is a complete nutrient source for humans. The quality and safety of milk are critical for both producers and consumers, thereby the dairy industry requires rapid and nondestructive methods to ...ensure milk quality and safety. However, conventional methods are time-consuming and laborious, and require complicated preparation procedures. Therefore, the exploration of new milk analytical methods is essential. This current review introduces the principles of Raman spectroscopy and presents recent advances since 2012 of Raman spectroscopic techniques mainly involving surface-enhanced Raman spectroscopy (SERS), fourier-transform (FT) Raman spectroscopy, near-infrared (NIR) Raman spectroscopy, and micro-Raman spectroscopy for milk analysis including milk compositions, microorganisms and antibiotic residues in milk, as well as milk adulterants. Additionally, some challenges and future outlooks are proposed. The current review shows that Raman spectroscopic techniques have the promising potential for providing rapid and nondestructive detection of milk parameters. However, the application of Raman spectroscopy on milk analysis is not common yet since some limitations of Raman spectroscopy need to be overcome before making it a routine tool for the dairy industry.
