查看更多>>摘要：? 2022 Elsevier B.V.Fluorescence microscopy is an extremely powerful technique that allows to distinguish multiple labels based on their emission color or other properties, such as their photobleaching and fluorescence recovery kinetics. These kinetics are ideally assumed to be mono-exponential in nature, where the time constants intrinsic to each fluorophore can be used to quantify their presence in the sample. However, these time constants also depend on the specifics of the illumination and sample conditions, meaning that identifying the different contributions in a mixture using a single-channel detection may not be straightforward. In this work, we propose a factor analysis approach called Slicing to identify the different contributions in a multiplexed fluorescence microscopy image exploiting a single measurement channel. With Slicing, a two-way dataset is rearranged into a three-way dataset, which allows the application of a trilinear decomposition model to derive individual profiles for all the model components. We demonstrate this method on bleaching - recovery fluorescence microscopy imaging data of U2OS cells, allowing us to determine the spatial distribution of the dyes and their associated characteristic relaxation traces, without relying on a parametric fitting. By requiring little a priori knowledge and efficiently handling perturbation factors, our method represents a general approach for the recovery of multiple mono-exponential profiles from single-channel microscopy data.
查看更多>>摘要：? 2022 Elsevier B.V.Rice is an important crop that provides energy and nutrients to humans, which undergoes the aging process, the quality decline is related to the exogenous storage conditions and the change of own enzyme activity. However, due to the complex composition of rice and serious matrix interference, the ageing identification of rice is still challenging. Hence, a novel spinel particles ZnFe2O4@PANI was designed and synthesized for adsorption and determination of vitamin B9, which can be used to distinguish rice in different years and analyze the degree of aging. The ZnFe2O4@PANI showed large specific surface area and fast mass transfer rate with good linear correlation coefficient (R2 = 0.9965), satisfactory recoveries (85.1%–99.9%) and relative standard deviations (RSD, 9.3%). Moreover, the π-π electron-donor-acceptor (EDA) and intermolecular hydrogen-bonding interactions of polyaniline coating provided selective adsorption on vitamin B9. Adsorption thermodynamics study suggested that the adsorption reactions were spontaneous, endothermic and thermodynamically favorable. Finally, ZnFe2O4@PANI was used to evaluate vitamin B9 in rice from different years, which laid a theoretical foundation for exploring the relationship between vitamin changes and the aging degree of the rice.
查看更多>>摘要：? 2022 Elsevier B.V.Separation, purification, and identification of glycoproteins are essential for understanding their vital roles in biological and pathological processes. However, glycoproteins are difficult to be captured due to their low abundance, strong interference from non-glycosylated proteins. Here, we report a promising dipeptide-based saccharide recognition platform to selectively enrich two typical glycoproteins, named immunoglobin G (IgG) and horseradish peroxidase (HRP). Different from the conventional glycoprotein enrichment method based on boronic acid affinity or hydrophilic interaction with glycans, the present method was established based on affinity between Pro-Glu (PE) dipeptide and mannose, which is a key unit in the pentasaccharide core of the IgG and HRP glycans. The prepared PE homopolymer surface was proved to selectively bind IgG and HRP superior to that of bovine serum albumin (BSA). Benefiting from this feature, selective enrichment of IgG and HRP was achieved from a protein mixture containing 200-fold BSA interference by using polyPE@SiO2 under a dispersive solid-phase extraction (dSPE) mode. High adsorption capacity, controllable and selective adsorption behaviors, as well as satisfactory recovery demonstrated the high potential of the dipeptide-based polymeric material in IgG and HRP enrichment. This study might provide a new insight to solve the challenging problem of glycoprotein separation.
查看更多>>摘要：? 2022In this work, a red, green, blue (RGB) color sensor was used for quantitative optical analysis of colored solutions. The capability of the sensor to respond to different colored solutions was critically evaluated to better understand which spectral bands are filtered and processed by each sensor channel. The effective capability of the RGB sensor, defined as its ability to illuminate and detect electromagnetic radiation reflected by the samples, was observed in the range of 415–564, 440–600 and 510–750 nm for blue, green and red channels, respectively. These results can help understand the interaction between the light emitted by the sensor and the signals obtained by the RGB channels for different quantitative determinations. In order to investigate the interaction between the RGB sensor and colored substances, and thereafter achieve quantitative optical analysis, different colored dyes were chosen to evaluate the RGB sensor capability, thus covering a wide range of colors. The analytical performance of the RGB sensor yielded a linear range of 5.0–50.0 μmol L?1 for dye solutions. The accuracy of this sensor was demonstrated by the thiocyanate method for colorimetric determination of iron in soil and supplement samples. Such RGB sensor achieved analytical performance similar to that obtained with the commercial spectrophotometer, without requiring the use of computers for image processing so as to gather RGB values. Additionally, this sensor also contributes to meeting the requirements of Internet of Analytical Things (IoAT) for the quantitative analysis of colored solutions.
查看更多>>摘要：? 2022Fluorescent biosensors and imaging devices have gained fervent consideration due to their prime functionality in biological. Among fluorescent nanomaterial (FNMs), the ultra-small gold nanoclusters (AuNCs) have gained promising attention with respect to extra-ordinary properties of bright fluorescence, economical synthesis, higher photostability, and biocompatibility, and deep tissue penetration. Therefore, the prior decades comprehended the revolutions in the field of real-time monitoring devices, nanotechnology-based biosensing, and bioimaging sensors. The present review primarily focuses on metal NCs (MNCs) and their advantages, a brief introduction of AuNCs along with history prospective and development, fundamental aspects regarding AuNCs quality and fluorescence, limitations and advantages of AuNCs, sensing mechanism, expected synthesis principle, and summarized the recent progress of AuNCs probe over the last 3 years (2019–2021) with their respective detection and bioimaging mechanism and synthesis principle. Moreover, the present work also serves as a novel stratagem for the preparation and potential applications of multifunctional AuNCs nano-systems responsiveness for various analytes detection and cell bioimaging with respective examples. At last, we described the challenges associated with the application of AuNCs based on recent signs of progress.
查看更多>>摘要：? 2022 The AuthorsThis work reports the first electrochemical bioplatform for the determination of soy traces in food. The bioplatform involves sandwich-type immunoassays using specific antibodies for β-conglycinin and glycinin, which are the main allergenic soy proteins, and carboxylic acid-modified magnetic microbeads. Amperometric detection at ?0.20 V (vs. an Ag pseudo-reference electrode) was performed using single or dual screen-printed carbon electrodes and the H2O2/hydroquinone (HQ) system. The measured variation in the cathodic current was directly proportional to the concentration of target allergenic proteins. The developed bioplatforms exhibit a good selectivity and sensitivity providing limits of detection (LOD) values of 0.03 and 0.02 ng mL?1 for β-conglycinin and glycinin, respectively. The determination of both proteins can be carried out in only 1.5 h. The electrochemical bioplatforms allow their accurate determinations (with results statistically comparable to those provided by ELISA methodologies) in raw cookie dough and baked cookies enriched with soy flour. The results obtained confirm, in a pioneering way with electrochemical biosensors, the possibility of discriminating samples incurred with as little as 0.0005 ppm of a food allergen in model cookie extracts.
查看更多>>摘要：? 2022 Elsevier B.V.Conductive composite fibers containing poly (3,4-ethylenedioxythiophene) (PEDOT) and silver nanoparticles (AgNPs) were fabricated by emulsion electrospinning of 2,5-dibromo-3,4-ethylenedioxythiophene (DBEDOT) in toluene together with aqueous solution of poly (vinyl alcohol) (PVA) and silver nanoparticles (AgNPs) in the presence of sodium dodecylsulfate followed by heat treatment at 70 °C to convert DBEDOT to conductive PEDOT via solid state polymerization (SSP). The composite fibers were characterized by scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy and thermogravimetric analysis. The PEDOT/PVA/AgNPs composite fibers deposited on a screen-printed carbon electrode (SPCE) surface exhibited good electrochemical response and was applied for simultaneous detection of heavy metal ions in a mixture, namely Zn(II), Cd(II), and Pb(II) via square wave anodic stripping voltammetry (SWASV). With added Bi+3 into the detection system, the bismuth film formed on the electrode allows effective alloy formation with the deposited heavy metals obtained upon reduction of the heavy metal ions, the detection of heavy metal ions after stripping was successfully accomplished with a linear range of 10–80 ppb and limits of detections (LOD) of 6, 3 and 8 ppb for Zn(II), Cd(II), and Pb(II), respectively.
查看更多>>摘要：? 2022Multiplexing the ion packet injection with advanced signal processing is an effective method to improve both the ion throughput and signal-to-noise ratio for ion mobility spectrometry. Generally used multiplexing methods include Hadamard transform ion mobility spectrometry (HT-IMS), Fourier transform ion mobility spectrometry (FT-IMS), and correlation ion mobility spectrometry (C-IMS). However, HT-IMS sometimes suffer from false peaks and further processing is needed, FT-IMS generally requires longer spectra acquisition time than the traditional signal averaging method, and C-IMS also demonstrated drawbacks such as spectra baseline distortions when using traditional on-off binary gating switches. To improve the performance of multiplexing ion mobility spectrometry, this study investigates the Fourier deconvolution to increase the resolving power and signal-to-noise ratio at the same time. This approach modulates the ion gate with a linear square wave chirp sequence and synchronizes the data acquisition and ion gate modulation and then reconstructs the ion mobility spectra based on convolution theorems. The equivalent ion injection period is decreased to microseconds scale with the signal-to-noise ratio improved by up to 13 times on average, and the resolving power is improved by up to 50% compared with traditional signal averaging methods without hardware modifications.
查看更多>>摘要：? 2022 Elsevier B.V.Detection of heavy metal ions (HMIs) in water is an important topic in the field of analytical chemistry and environmental science. Fluorescence spectroscopy is one of the most promising strategies due to its simple instrument, low investment, rapid and convenient operation. However, current fluorescence probes for detecting HMIs are typically selective for certain ions. Herein we reported the development of a novel strategy that determined the total content of HMIs in water by fluorescence spectroscopy. A novel fluorescent nitrogen, sulfur co-doped carbon quantum dots (N, S-CQDs) was prepared via graphene oxide-assisted synthesis method. The results showed that, with the fluorescence quenching strategy, N, S-CQDs exhibited a wide linear response to a series of water-soluble metal ions. The fluorescence of N, S-CQDs is stable in a wide range of pH 4–11. The detection mechanism was proved that the integration, caused by coordination interaction between S element in N, S-CQDs and the d-orbital of associated metal ions, was the main reason for fluorescence quenching. In practice, the N, S-CQDs were applied to determine total content of HMIs in water successfully. Interestingly, further experiment proved that the N, S-CQDs could effectively remove HMIs in water after centrifuging and filtering thoroughly. It was shown that the fluorescence of N, S-CQDs was obviously quenched by the multiple-ions-involved water and scavenging effect of N, S-CQDs on HMIs with centrifugal in which the concentration of individuals meets the Chinese National Standard. This indicates that the N, S-CQDs are of a wide application prospect in water quality analysis.
查看更多>>摘要：? 2022 Elsevier B.V.Molecularly imprinted polymers (MIPs) are artificial chemical receptors, and can recognize template molecules with a high selectivity and affinity. As “antibody mimics”, MIPs have been widely studied in various fields. However, the general applicability of MIPs is limited by the type of functional monomers. Herein, we developed caffeic acid (CA, a natural polyphenol) as novel a functional monomer. An innovative poly(caffeic acid)-coated molecularly imprinted magnetic nanoparticles (PCA-MIMN) with transferrin (TRF) as a model glycoprotein template was fabricated by autoxidation of CA with hexamethylenediamine (HMDA) in an aerobic environment as imprinted layer. The successful fabrication of PCA-MIMN was proved in detail by diversified characterization. The PCA-MIMN exhibited not only outstanding binding affinity and specificity for target glycoprotein, but also excellent hydrophilicity due to the externally generous hydrophilic groups. To evaluate the preeminent performance, the PCA-MIMN was linked with pH-triggered allochroic-graphene oxide (AGO), which was used for determination of TRF in real samples. The proposed PCA-MIMN linked AGO strategy exhibited ultrahigh sensitivity with limit of detection of 0.38 pg mL?1 for TRF. Finally, the proposed strategy was successfully applied in determination of TRF in spiked human serum sample with recovery and relative standard deviation in the range of 97.2%–103.9% and 4.6%–5.8%, respectively. This work demonstrates that the “autoxidation of CA with HMDA” may be a universal tool for synthesis of highly specific MIPs, and the type of functional monomers will increase exponentially due to the presence of numerous polyphenols in nature.
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