Analysis & sensing最新文献

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.

Editor in Chief Jonathan Faiz looks back at the developments in Analysis & Sensing in 2022, and introduces our new Commissioning Editors.

We report here a colorimetric carbon dioxide (CO₂) optode sensor with a polypropylene microporous membrane on top of a thin layer (30 μm) of polyurethane hydrogel. The diffusion of CO₂ across the polypropylene membrane induced pH changes in the hydrogel containing a lipophilic indicator, a cation exchanger, and a cationic amine. The ratio of the indicator and the cation exchanger was successfully utilized to adjust the sensitivity of the CO₂ response. Increasing the relative amount of the cation exchanger made the sensor much more sensitive to CO₂ in the lower concentration range. Moreover, the carbarmic formation reaction between the primary amine and CO₂ was investigated. The results indicated a very small contribution of carbarmic formation to the overall pH change. With a detection limit of 0.014 % for the CO₂ partial pressure, the sensor was successful applied to monitor CO₂ evolution during yeast catalyzed flour fermentation.

Chemiluminescence (CL) provides ideal conditions for point-of-care testing (POCT) with wide dynamic ranges, superior sensitivities, and detection simplicity. It has not arrived routinely in the POCT field due to naturally low quantum yields of typical probes and the lack of sensitive low-cost detection devices. Here, we developed a universal microfluidic paper-based analytical device (μPAD) using l-lactate as model analyte. We demonstrate that a smartphone camera can compete with a scientific CCD camera as performance benchmark when using the strong CL emitter, m-carboxy luminol, resulting in extraordinary signal-to-noise ratios of 67. The μPAD provides CV<10 %, stability at room temperature for≥3 months and simple processing. Furthermore, the μPAD enables the detection of picomoles of the luminophore providing additional design flexibility. Thus, this new CL-μPAD is available for translating the many CL standard analytical assays performed in microtiter plates, microarrays or other more complex detection strategies to the POC.

Catalytic hairpin assembly (CHA), as an enzyme-free isotheral nucleic acid amplification method, can easily cooperate with other amplification procedures to improve the sensitivity and accuracy of detection. Herein, we constructed a cascaded CHA sensing platform for breast cancer biomarker detection. Introducing a short double nucleic acid stand avoids the product of CHA1 to directly trigger the CHA2 reaction, which simplifies the design of the CHA hairpins. Compared with the single CHA2 reaction, the cascaded CHA biosensor activated by microRNA-155 holds nearly 10 times the amplification efficiency with detection limit down to 47.4 pM and quantifies the target in the range from 50 pM to 200 nM. Besides, the magnetic bead-confined CHA2 taking 3D DNA walking as the display form contributes to decreasing the environmental interference. As expected, the strategy sensitively distinguishes expression levels of microRNA-155 in different cell lines and cancer patients, which are consistent with the results of traditional qRT-PCR method. More importantly, simply adjusting the microRNA recognition sequence of CHA1 can extend the cascaded CHA platform to a wider detection range. Therefore, the robustness and efficiency of the approach enable the potential applications for detection of microRNA and early clinical disease diagnosis.

The cover feature image shows a fast-responding gating system by using horseradish peroxidase (HRP)-loaded functional RNA superstructures (HRP@3D RNA). The specificity of RNA aptamer-ligand interaction serves as a triggered manner to release the loaded HRP from HRP@3D RNA. Based on this, a disposable origami paper-based analytical device (doPAD) was developed for tetracycline (TC) detection. More information can be found in the Research Article by Meng Liu and co-workers.

Invited for this month′s cover is the collaborating groups of Prof. Sho Hideshima at Tokyo City University, Prof. Tetsuya Osaka at Waseda University, and Prof. Hiroaki Tateno at National Institute of Advanced Industrial Science and Technology, Japan. The cover picture shows a semiconductor-based biosensor with potential to detect the presence of a specific biomarker of human induced pluripotent stem cell (hiPSCs) in a culture medium. More information can be found in the Research Article by S. Hideshima, T. Osaka, and co-workers.