查看更多>>摘要：This paper presents the study of selected painted fragments from different contexts of Ostia Antica city, dating between 2nd century BCE and the end of the 1st century CE. The aim is to identify the raw materials used and to understand the execution techniques through a non-invasive protocol including techniques based either on multiband imaging (Visible-VIS, Ultraviolet induced Luminescence - UVL and Visible Induced Luminescence - VIL) and single spot analyses (Fiber Optic Reflectance Spectroscopy-FORS and portable X-Ray Fluorescence spectrometry - XRF). The most representative and interesting fragments were sampled for further studies with laboratory techniques such as optical microscopy (OM) and electron microscopy (SEM), Fourier Transform Infrared and micro-Raman Spectroscopies (FT-IR and mu Raman). The extensive use of non-invasive techniques, even working on fragments, is proved to be the most robust and effective approach enabling the analysis of a high number of areas, dramatically increasing the statistical meaning of the collected data. The elaboration of such a huge number of data allows highlighting differences and similarities, thus achieving a more realistic overview of the materials composition and addressing the sampling to the more significant and complex areas. (C) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：Both electroporation-assisted and ultrasound-assisted delivery methods can rapidly deliver nanoparticles into living cells for surface-enhanced Raman scattering (SERS) detection, but these two methods have never been compared. In this study, electroporation-assisted SERS and ultrasound-assisted SERS were employed to detect the biochemical changes of degranulated mast cells induced by mast cell stimulator (C48/80). The results showed that the cell damage of electroporation based on controllable electric pulse was smaller than that of ultrasound based on cavitation. Transmission electron microscope images of cells indicated that the nanoparticles delivered by electroporation were mainly distributed in the cytoplasm, while ultrasound could transport nanoparticles to the cytoplasm and nucleus. Therefore, electroporation-assisted SERS mainly detects the biochemical information of cytoplasm, while ultrasound-assisted SERS gets more spectral signals of nucleic acid. Both methods can obtain high quality SERS signal of cells. With drug treatment, the SERS peak intensity of 733 cm-1 attributed to phosphatidylserine decreased significantly, which may be due to the activation of mast cell degranulation pathway stimulated by C48/80 agonist, resulting in a large amount of intracellular serine being used to synthesize tryptase, while the production of phosphatidylserine decreased. Further, based on principal component analysis and linear discriminant analysis (PCA-LDA approach), ultrasound-assisted SERS could achieve better sensitivity, specificity and accuracy in the discrimination and identification of drug-treated degranulated mast cells than electroporation assisted SERS. This exploratory work is helpful to realize the real-time dynamic SERS detection of intracellular biochemical components, and it also has great potential in intracellular SERS analysis, such as the cytotoxicity assay of anti-tumor drugs or cancer cell screening. (c) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：In this study, a novel FONs-based sensor P-M(w) was synthesized using 1-Pyrenecarboxaldehyde and L-methionine through facile hydrothermal strategy. The fluorescence emission peaks of the acquired P-M (w) would show specific changes after the addition of Hg2+ due to interfering the PET process and inducing nano-structure conformational rigidification of P-M(w). Notably, the water-soluble FONs-based sensor was firstly used to detect Hg2+ in tea samples providing a new material choice for the fluorescence sensor construction of metal ion detection. Besides, the qualitative and quantitative analysis of Hg2+ could be carried out with P-M (w) at a very low concentration (1 mu g/mL) meaning that the acquired PM(w) synthesized by few grams of reactants may satisfy the detection of approximate fifty thousand samples. (C) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：In this study, we characterize the solution processed tris-(8-hydroxyquinoline)aluminum(Alq(3))/ZnO hybrid thin films using Raman and X-ray photoelectron spectroscopic (XPS) techniques. Raman studies reveal the sol-gel derived spin-coated ZnO thin film has hexagonal wurtzite structure. The incorporation of Alq(3) molecules in the hybrid film results in the formation of bonding onto the surface of highly crystalline ZnO nanoparticles. The XPS confirms the incorporation of Alq(3) in the hybrid thin films and corroborates that the Alq(3) molecules may be adsorbed onto the surface of ZnO nanoparticles (chemisorption), showing the existence of chemical interaction between Alq(3) and ZnO in the hybrid films. These studies support that the chemisorbed Alq(3) molecules onto the ZnO nanoparticles may facilitate the charge transfer (non-radiative) between Alq(3) and ZnO in the hybrid thin films which will be useful to enhance the optical and electrical properties for the optoelectronic device applications. (C) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：A series of novel La9.31Si6.24O26:Er3+,Yb3+ (LS:Er3+,Yb3+) luminescent materials have been successfully synthesized by conventional solid-state reaction method. The phases, morphologies and upconversion (UC) luminescence properties were systematically researched by XRD, SEM, PL spectra, etc. The optimum Yb3+ concentration in LS:1%Er3+,xYb(3+) was determined to be x = 15%, above which the concentration quenching effect appeared due to the increasing energy back transfer from Er3+ to Yb3+. Meanwhile, the FIR technique (by using I-522/I-554 and I-660/I-522 of Er3+) was employed to study the temperature-sensing performance. As the rise of temperature for all the different Yb3+ concentrations, the values of the absolute sensitivity S-A increased first and then decreased by utilizing I-522/I-554, but showed continuous decrease by using I-660/I-522. For the relative sensitivity S-R, it has been found that the S-R values for all the samples exhibited gradual decrease with rising temperature. Besides, the experiment of the heating-cooling cycles between 283 and 523 K proved that the LS:Er3+,Yb3+ material has good reversibility and repeatability. The above results indicated that the LS:Er3+,Yb3+ may be a potential candidate for optical temperature sensor. (C) 2021 Elsevier B.V. All rights reserved.
Kalita, PriyankiSingh, Ranjan K.Bhattacharjee, Ayon
13页
查看更多>>摘要：Liquid crystals (LCs) are a promising system of molecules for biosensing as a transducing agent for detecting protein human serum albumin (HSA). Herein, we investigate the detection of HSA by a liquid crystal 40-octyl-4-biphenylcarbonitrile (8CB) intending to develop an LC-based biosensor. The change in the alignment of liquid crystal molecules in the presence of protein results in the transfigurations of the director through interactions. The limit of 8CB to detect HSA is found to be at a reliable concentration in the development of biosensors. The transition in the director configurations from radial to bipolar during the crystalline to the isotropic phase of the liquid crystals are studied under polarizing optical microscopy. These transitions confirm the detection of HSA by 8CB. The docking analysis depicts the interactions by which 8CB liquid crystal molecules bind with protein HSA. The binding energy, binding active residues and their distances between the docked residues of HSA and molecules of ligand 8CB are calculated by molecular docking. Temperature-dependent Raman spectroscopy is used to analyse the spectral behaviour of the interactions. The residues validated by molecular docking studies correlate well with the findings of Raman spectra for the interaction between 8CB and HSA. (C) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：This paper mainly focuses on the feasibility of rapidly identifying Fritillariae cirrhosae varieties, distinguishing its authenticity and detecting its components by using a portable near infrared (NIR) spectrometer. Five different varieties of Fritillariae cirrhosae, five common counterfeits and two main components (ethanol-soluble extractives and total alkaloids) were studied. The reference values of ethanol-soluble extractives were determined by hot dip method and the reference value of total alkaloid was determined by ultraviolet-visible spectrophotometry (UV-Vis). Linear discriminant analysis (LDA) algorithm was used to identify the sources of different varieties of Fritillariae cirrhosae and the common counterfeits of Fritillariae cirrhosae, respectively. As a result, the best models seemed to be effective, with accuracy of the two models' prediction sets reaches 83.33% and 90.91%, respectively. The partial least squares regression (PLSR) algorithm was used to relate the sample spectra with the reference values of ethanol-soluble extractives and total alkaloid content. Coefficient of determination of prediction (R2p) and root mean square errors of prediction (RMSEP) obtained were 0.8562 and 0.3911; 0.6917 and 0.0117, for ethanol-soluble extractives and total alkaloid content, respectively. The results showed that the portable NIR spectrometer could evaluate the quality of Fritillariae cirrhosae with high efficiency and practicability. (c) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：A label-free sensing strategy based on the enzyme-mimicking property of Glutathione-Ag nanoparticles (GSH-AgNPs) was demonstrated for colorimetric detection of vitamin B1 (VB1). Firstly, obvious blue color accompanied with an absorption peak at 652 nm was observed due to the high peroxidase-like activity of GSH-AgNPs towards 3,3',5,5'-tetramethylbenzidine (TMB). Then, in the presence of VB1, the mimetic activity of GSH-AgNPs could be strongly restrained, evidenced as a promiment colorimetric change to colorless, which can be used to achieve the visualization detection VB1. Linear relationship between absorbance response and VB1 concentration from 0 to 0.2 mu M were obtained. The detection limit was calculated as low as 40 nM. The inhibition reasons were thoroughly discussed. Considering the advantages of rapid response, easy procedure and high selectivity, the proposed method possesses potential application in environment and biological analysis for VB1 detection. (C) 2021 Elsevier B.V. All rights reserved.
Ribeiro, Ana Rubia BatistaSilva, Elaine Cristina OliveiraAraujo, Polliane Maria CavalcanteFonseca, Eduardo Jorge da Silva...
11页
查看更多>>摘要：Macrophages are key cells in the immune inflammatory response that can be differentiated into M1 and M2 phenotypes. Polarization has a critical therapeutic value, especially in diseases in which an M1/M2 imbalance plays a pathophysiological role. Raman spectroscopy has proven to be a promising bioanalytical technique for discriminating different cell types. However, to our knowledge, its application to identify the functional polarization of macrophages into M1 or M2 cells is yet to be investigated. In this work, Raman spectroscopy was applied to the analysis of macrophage polarization, and the spectral datasets were analyzed using principal component analysis (PCA). In vitro, resting J774.1 macrophages were treated with LPS/IFN-gamma to induce the M1 phenotype or with IL-4 to induce the M2 phenotype. The resulting Raman spectra showed sufficient biochemical information to distinguish between M1 and M2 phenotypes when analyzed by PCA, reflecting the changes in cell markers caused by differentiation. The Raman spectra collected from LPS-stimulated M1 and M2 macrophages were more intense. The functional phenotype of M1 macrophages was confirmed by IL-6 secretion and TNF-alpha mRNA expression, while M2 macrophages produced IL-10 and Arg-1 mRNA, as well as by the morphological changes observed by scanning electron microscopy. Taken together, the results indicate that Raman spectroscopy combined with PCA analysis is a useful tool to identify the functional phenotypes of macrophages, providing an alternative way to distinguish between cells in distinct differentiation stages. (C) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：A new method was developed for selectively and rapidly detecting carcinogen 4-aminobiphenyl, with lower limit of detection and wider linear range. Up-conversion nanoparticles beta-NaGdF4:Yb3+, Er3+ was the first time to choose as light-emitting signal component. Molecularly imprinted polymers (MIPs) with specific recognition ability were successfully coated on the surface of beta-NaGdF4:Yb3+, Er3+ to obtain a nano fluorescent probe for detecting 4-aminobiphenyl. The effect of addition amount of beta-NaGdF4: Yb3+, Er3+ on the detection ability of alpha-NaGdF4:Yb3+, Er3+@MIPs was studied, and composite fluorescence nanoprobe with the best performance was obtained. beta-NaGdF4:Yb3+, Er3+@MIPs were characterized by transmission electron microscopy, X-ray powder diffractometer, Fourier transform infrared spectroscopy and thermogravimetric analysis. The fluorescence intensity of beta-NaGdF4:Yb3+, Er3+@MIPs decreased significantly compared with molecularly non-imprinted polymers beta-NaGdF4:Yb3+, Er3+@NIPs (the maximum emission peak is at 541 nm) in the presence of 4-aminobiphenyl. Adsorption isotherm and adsorption kinetics between UCNP@MIPs and 4-ABP have been investigated and a satisfactory imprinting factor is 2.5. The detection mechanism is proved to be based on Langmuir adsorption and internal filtration effect. Under optimal experimental conditions, the limit of detection and quantification are 0.16 mu M and 0.53 mu M, respectively. The linear range of response is 1-50 mu M, and RSD is less than 6.7%. This method was applied to determining river water samples in order to evaluate the practicability, and the good recovery rate is between 98.89% and 109.7%. These evidences demonstrate that beta-NaGdF4:Yb3+, Er3+@MIPs is successfully used for the detection of 4-aminobiphenyl. (C) 2021 Elsevier B.V. All rights reserved.
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Elsevier