Published by: The Royal Society of Chemistry
Total articles ≅ 40,348
Latest articles in this journal
The Analyst; https://doi.org/10.1039/d2an01850k
Nanozymes have been widely used to construct colorimetric sensors due to their advantages of cost-effective, high stability, good biocompatibility, and ease of modification. The emergence of nanozymes greatly enhances the detection sensitivity and stability of the colorimetric sensing platform. Recent significant research has focused on designing various sensors based on nanozymes with peroxidase-like activity for colorimetric analysis. However, with the deepening of research, nanozymes with peroxidase-like activity also expose some problems, such as weak affinity and low catalytic activity. In view of the above issues, existing investigations have shown that the catalytic properties of nanozymes can be improved by adding surface modification and changing the structure of nanomaterials. In this review, we summarize the recent trends and advances of colorimetric sensors based on several typical nanozymes with peroxidase-like activities, including noble metals, metal oxides, metal sulfides/metal selenides, carbon and metal-organic frameworks (MOF), etc. Finally, the current challenges and prospects of colorimetric sensors based on nanozymes with peroxidase-like activity are summarized and discussed to provide a reference for researchers in related fields.
The Analyst; https://doi.org/10.1039/d2an01603f
The combination of single-cell Raman microspectroscopy (SCRM) and stable isotope probing (SIP) enables in-situ tracking of carbon or hydrogen fluxes into microorganisms at the single-cell level. Therefore, it has high...
The Analyst; https://doi.org/10.1039/d2an01798a
We report here the construction of a programmable catalytic molecular nanomachine based on cross-linked catalytic hairpin assembly (CCHA) reaction for one-step highly sensitive detection of proteins and small molecules. For this system, when the recognition elements attached on split initiators bind to the target proteins, it can trigger the cascade of CCHA reaction, resulting in the formation of many macromolecular fluorescent products for signaling. This platform couples the advantages of highly efficient DNA-based nanotechnology with specific protein-small molecule interaction. We demonstrate sensitive detection of streptavidin and anti-digoxigenin antibody with the detection limit down to 48.8 pM and 0.85 nM, respectively. This nanomachine is flexible, we also display nanomolar detection of the corresponding small molecules such as biotin and digoxigenin, using a competitive method. In addition, the nanomachine is robust enough to perform well in human serum samples. Overall, this programmable catalytic molecular nanomachine provides a versatile platform for the detection of other proteins and small molecules by replacing the recognition elements, which will promote the development of DNA nanotechnology in disease diagnosis and therapeutic drug monitoring.
The Analyst; https://doi.org/10.1039/d2an01321e
In this study, a cathodic intra-molecular electrochemiluminescence resonance energy transfer (ECL-RET) probe was exquisitely designed via the integration of an ECL donor (Cu NCs) with an acceptor (Ru(dcbpy)32+), and further employed the 3D bipedal DNA walker amplification strategy to monitor the platelet-derived growth factor BB (PDGF-BB). Specifically, blue emission Cu NCs with low consumption, biocompatibility and numerous resources, act as well-overlapped donors and significantly improve the ECL efficiency of Ru(dcbpy)32+. More impressively, the intra-molecular ECL-RET of Cu NC-Ru endowed a better and more stable ECL signal by reducing the electron-transfer distance and decreasing the energy loss. Furthermore, 3D bipedal DNA walker amplification was employed to efficiently convert the target PDGF-BB into numerous DNA strands, achieving sensitive target amplification. By virtue of such design, the constructed aptasensor exhibited a sensitive and selective assay for PDGF-BB with a detection range from 0.01 pM to 10 nM and a detection limit of 3.3 fM. The intramolecular ECL-RET and 3D bipedal DNA walker amplification strategy designed in this study will provide valuable insight into promising ultrasensitive ECL bioanalysis.
The Analyst; https://doi.org/10.1039/d2an01771g
L-Cysteine is a common amino acid, which plays an important role in human livelihood and production. Therefore, a novel method for simultaneous quantitative and qualitative determination of L-Cysteine by colorimetric detection system was proposed. As a viable oxidase mimic, [N4444]Cl-G/MnO2 consisted of MnO2 nanosheet which functionalized by tetrabutylammonium chloride-glycerol ([N4444]Cl-G) based deep eutectic solvent (DES). Owing to the oxidation of MnO2 nanosheet, the [N4444]Cl-G/MnO2 could oxidize the colorless 3,3’,5,5’-tetramethylbenzidine (TMB) into a blue product (oxTMB) with a characteristic UV-vis spectrum absorbance at 652 nm. The oxidation of TMB by [N4444]Cl-G/MnO2 was inhibited when L-cysteine was introduced, and the absorbance decreased proportionally with the increase of L-cysteine concentration. Due to this inhibition effect, a colorimetric detection system ([N4444]Cl-G/MnO2-TMB) for quantitative determination of L-Cysteine was schemed out. Under optimal conditions, the assay showed good linearity over the concentration ranges of 0.125-2.00 μg·mL-1 with a low detection limit of 5.96 ng·mL-1, respectively. The study of inhibition mechanism demonstrated that the sulfhydryl group of L-Cysteine could decompose [N4444]Cl-G/MnO2 into Mn2+, thus limiting the conversion of TMB to oxTMB. In addition, the DES/MnO2-TMB system had been used in test strips for visual-qualitative detection of L-Cysteine. Finally, the selectivity and test strip results illustrated the [N4444]Cl-G/MnO2-TMB system exhibited high selectivity, simple operation, rapid response for qualitative detection of L-Cysteine. Due to the satisfying performance of detection strategy, the colorimetric sensing based on [N4444]Cl-G/MnO2-TMB system has a prospective application value in quantitative and qualitative detection of L-Cysteine.
The Analyst; https://doi.org/10.1039/d2an01471h
Tripterygium wilfordii Hook F from the family Celastraceae is a traditional Chinese medicine (TCM) whose principal chemical constituents are terpenoids, including sesquiterpene alkaloids and diterpenoids, which have unique and diverse structures and remarkable biological activities. In order to advance pharmacological research and guide the preparation of monomer compounds derived from T. wilfordii, a systematic approach to efficiently discover new compounds or their derivatives is needed. Herein, compound separation and identification were performed by offline reversed-phase × supercritical fluid chromatography coupled mass spectrometry (RP × SFC-Q-TOF-MS/MS) and Global Natural Product Social (GNPS) molecular networking. The 2D chromatography system exhibited a high degree of orthogonality and significant peak capacity, and SFC has an advantage during the separation of sesquiterpene alkaloid isomers. Feature-based molecular networking offers the great advantage of quickly detecting and clustering unknown compounds, which greatly assists in intuitively judging the type of compound, and this networking technique has the potential to dramatically accelerate the identification and characterization of compounds from natural sources. A total of 324 compounds were identified and quantitated, including 284 alkaloids, 22 diterpenoids and 18 triterpenoids, which means that there are numerous potential new compounds with novel structures to be further explored. Overall, feature-based molecular networking provides an effective method for discovering and characterizing novel compounds and guides the separation and preparation of targeted natural products.
The Analyst; https://doi.org/10.1039/d2an01674e
In this work, we have meticulously tuned the carcinogenic congo red dye to environmentally benign fluorescent carbon dots (CDs) by adopting a typical hydrothermal method without any additives. As synthesized CDs were extremely water soluble, exhibited an excitation wavelength independent emission with a high fluorescence quantum yield (46%) and were biocompatible. The microscopic results revealed that the CDs were quasi-spherical with a particle diameter of ~5 nm. The structure and functional groups of CDs were comprehensively investigated using Fourier-transform infrared, X-ray photoelectron and Raman spectroscopic analysis. These studies show that the CDs were intrinsically functionalized with –OH, N–H and C=O groups. In the sensing experiments, the CDs selectively responded to Fe3+ ions over other analytes with a detection limit of 12 nM. The time-resolved fluorescence quenching measurements were used to decipher the sensing mechanism. For onsite ‘equipment-free’ detection of iron, we have developed CDs adsorbed paper-based analytical tool. Furthermore, the selective nature of CDs was successfully employed to detect Fe3+ in non-heme metalloprotein (ferritin) and real water samples. Thus, the CDs produced from congo red dye could be a prospective asset to the bio-imaging and biosensing research fields.
The Analyst; https://doi.org/10.1039/d2an01657e
The continuous and excessive use of agrochemicals for the crop improvement and protection has raised a widespread concern, as they exert adverse effects on human health and local environment. Surface Enhanced Raman Spectroscopy (SERS) provides a method for the quick identification and detection of such hazardous substances in a short amount of time due to its properties of being robust, accurate, sensitive and non-destructive. Despite the fact that several SERS substrates have been developed, the bulk of them are ineffective in terms of sample collecting or providing reproducible results. In this study, we showed that a 3-D wrinkled polymeric heat-shrink film coated with Au [email protected] nanorods (silver nanorods) serves as a potential SERS substrate for trace analysis. The surface of the heat-shrink film became wrinkled after heating, and this, along with the spatial arrangement of nanoparticles, significantly enhances the Raman signal of the analytes. The fabricated SERS substrate was able to sense two model analytes 1,4-benzenedithiol (BDT) and 2-naphthalenethiol (NT) up to 10-13 M and 10-11 M concentrations. The fabricated substrate was also effective in sensing thiram down to 10-13 M concentration. Additionally, the SERS substrate was applied in a real-world setting for the detection of pesticide thiram spiked onto apple skin surfaces. To collect the thiram residues, the substrate was simply swabbed across the surface of the apple. This allowed for the detection of thiram at concentrations as low as 10-9 M (1 ppb). The fabricated SERS substrate can thus detect analytes in an efficient, sensitive, and dependable and accurate manner, allowing for the sensing of trace analytes like pesticides in a real-world environment.
The Analyst; https://doi.org/10.1039/d2an01747d
Circulating tumor cells (CTCs) are the important biomarkers of liquid biopsy. The number and heterogeneity of CTCs play an important role in the diagnosis of cancer and personalized medicine. However, owing to the low-abundance biomarkers of CTCs, conventional assays are only able to detect the CTCs at the population level. Therefore, there is pressing need of a high sensitive method to analyze the CTCs at the single-cell level. As one important branch of microfluidics, droplet microfluidics has become a high-throughput and sensitive single-cell analysis platform for the quantitative detection and heterogeneity analysis of CTCs. In this review, we focus on the discussion of the quantitative detection and heterogeneity analysis of CTCs using droplet microfluidics. The enabling technologies of droplet microfluidics especially the high-throughput droplet generation and the high-efficiency droplet manipulation are first discussed. Then, the recent advances on detecting and analyzing CTCs using droplet microfluidics from different aspects of nucleic acids, proteins, and metabolites are introduced. The purpose of this review is to provide guidance for the continued study of droplet microfluidics for CTC-based liquid biopsy.
The Analyst; https://doi.org/10.1039/d2an01604d
The stability of MOF plays one of the most important roles in material applications, while the delicate structure of MOFs is suffering from the limitation of poor alkali tolerance. A new biligand Zr-MOF (biUIO-66-NH2NO2) with alkali-resistance performance and active functional groups has been synthesized in this study. The biUIO-66-NH2NO2 demonstrated a much better stability in 1% NH3·H2O solution compared with its parent material, the UIO-66-NH2. Following a further immobilization of Zr4+ ions, the biDZMOF consisting of dual-zirconium centers was prepared and was further applied in global enrichment of phosphopeptides by avoiding instability of the enrichment materials in the essential alkali elution procedure for the phosphopeptide enrichment workflow. The alkali-resistance elution of phosphopeptides from the biDZMOF can be directly introduced to a tandem mass spectrometry system for peptide analysis without desalting treatment. 425 phosphopeptides in total in 3 independent samples were identified from 10 μL human saliva after enriched by biDZMOF. The improvement in the alkali resistance and successful post modification of biUIO-66-NH2NO2 suggest an efficient strategy to develop new types of MOF materials for application.