Analysis & sensing最新文献

Due to their important roles in medicine, the product of the Petasis reaction has attracted extensive interest in pharmaceutical, medical and chemical communities. Traditional three-component Petasis methods normally use various catalysts under harsh conditions (high temperature, microwave, etc.) for long reaction times. In this study, we developed a green and highly efficient microdroplet method for accelerating the Petasis reaction, which obtain good yields without the need of any catalysts under mild reaction conditions. The Petasis reaction in microdroplets was suitable for a variety of salicylaldehydes, arylboronic acids and amines. The Petasis reaction in microdroplets was accelerated by approximately 4 orders of magnitude by comparing the measured rate constants in bulk. Further, a scaled-up amount of 0.8 g h⁻¹ was achieved for the Petasis reaction in microdroplets. This study supplies not only a high-efficiency and environment-friendly methodology to constructing aryl amines in organic community but also a useful derivatization strategy for highly sensitive mass spectrometric detection of arylboronic acids and aryl aldehydes.

Among the many biological imaging techniques, magnetic resonance imaging (MRI) has been widely adopted for biomedical and clinical diagnostic applications, because of its ability to image deep tissues with high spatiotemporal resolution. Bioresponsive contrast agents are the key to expanding the diagnostic potential of MRI by providing anatomical information and discerning biochemical activity. Recent developments in the field of responsive and gadolinium-based agents have resulted in novel complexes that can sense their chemical microenvironments and thus study various functional processes in the tissue. Herein, we discuss the design and use of Gd(III)-based and bioresponsive MRI contrast agents for specific biological markers such as Ca(II) and Zn(II) cations and zwitterionic amino acid neurotransmitters. Combining their basic physicochemical characteristics with aspects that should be considered for their use in vivo would achieve the desired sensing features and enable their applications in functional molecular imaging to visualize essential biological processes.

The cover image illustrates the binding of a group of DNA aptamers selected to recognize the spike protein (S-protein) of SARS-CoV-2, the virus that causes COVID-19. The binding affinity for several key variants of the S-protein and the degree of overlapping of the binding sites of the aptamers on the S-protein have been comparatively examined. The design was created with Biorender.com. More information can be found in the Research Article by John D. Brennan, Yingfu Li, and co-workers.

The cover feature image shows a two-dimensional (2D) colorimetric carbon dioxide (CO₂) sensor composed of a gas-permeable polypropylene film (25 μm thick) and a signal transduction hydrogel layer (30 μm thick). The hydrogel layer contained a pH sensitive chromoionophore to indicate the CO₂ induced pH change, and a cationic amine to further capture CO₂ through the carbamate formation reaction. With this 2D colorimetric CO₂ optode, the CO₂ release from yeast-catalyzed flour fermentation was successfully monitored. More information can be found in the Research Article by Jingying Zhai, Xiaojiang Xie, and co-workers.

The cover image illustrates the principle of a newly developed chemiluminescence (CL) microfluidic paper-based analytical device (μPAD) that enables highly sensitive detection of any catalytic process in which H₂O₂ is produced. Through the use of a new, sensitive CL luminophore cell phone camera detection allows quantification on-site with the same sensitivity as afforded through a CCD camera in the lab. One-step reactions to time the catalytic reactions can easily be realized through a moveable barrier if desired. Lactate is detected with μM detection limits and three orders of magnitude dynamic range in sweat, the luminophore reaches a pM detection limit. Cover design by Simone Rink.  More information can be found in the Research Article by Antje Baeumner and co-workers .

The front cover represents a wearable biosensor for the digitalization of lactate in sweat during sport activity. The biosensor is integrated into a microfluidic system for continue lactate monitoring, producing reliable real-time profiles. Outcomes: Real-time sweat lactate assessment is a potential proxy of personalized training strategies in cycling. More information can be found in the Research Article by Maria Cuartero, Gaston A. Crespo, and co-workers.

Invited for this month′s cover are the collaborating groups of Prof. Cuartero and Prof. Crespo at KTH and UCAM universities with the participation of Dalarna University. The cover picture shows a wearable biosensor for the digitalization of lactate in sweat during sport activity. The biosensor is integrated into a microfluidic system for continue lactate monitoring, producing reliable real-time profiles. It was found out that real-time sweat lactate assessment is a potential proxy of personalized training strategies in sports such as cycling.“ More information can be found in the Research Article by Maria Cuartero, Gaston A. Crespo, and co-workers.

Legionella pneumophila is the causative agent behind the deadly waterborne disease Legionnaires’, which is commonly transmitted by the spread of contaminated droplets from cooling tower water samples. The lack of effective detection methods presents a challenge for L. pneumophila outbreak control. Previously, an RNA-cleaving DNAzyme called LP1 was reported to specifically target L. pneumophila. In this study, LP1 was immobilized onto agarose beads via streptavidin-biotin interaction to develop a bead-based fluorescence assay for L. pneumophila detection. This bead-based assay demonstrated excellent stability and functionality in various cooling tower water samples. To improve L. pneumophila monitoring in real-world samples, a lysozyme treatment was used to enhance L. pneumophila recognition. The limit of detection of this DNAzyme-based bead assay can reach 10³ CFUs in cell-spiked cooling tower water samples without cell culturing or signal amplification steps.

Recent years, molecular detection technology has been playing an unprecedentedly important role in disease prevention and public health. Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) systems such as CRISPR/Cas12a and CRISPR/Cas13a, have been increasingly used in the detection of nucleic acid molecules because of its collateral cleavage ability in recent years. Herein, we develop a universal CRISPR/Cas12a-assisted methodology based on a nucleic acid duplex switch structure that can distinguish different categories of targets, such as DNA, RNA and small molecules. It is worth noting that for nucleic acid detection, this method can significantly identify single base substitutions with high specificity, compared with other Cas12a-assisted biosensing systems. The experimental results suggest that this method has great specificity for different targets, promising to be applied to rapid molecular diagnosis.

Development of a fluorescent probe for activity-based sensing of activity of alcohol dehydrogenase, a key enzyme in ethanol biooxidation, is reported. A caged coumarin reporter is released upon the selective oxidation by the enzyme with a strong, >60-fold emission enhancement. The probe has a low cytotoxicity and has been applied in visualising alcohol dehydrogenase activity in HepG2, A549 and HEK293T cells, demonstrating its potential as a convenient, easy-to-use bioanalytical tools in unveiling the roles of the enzyme in alcohol metabolism.