Analysis & sensing最新文献

Metabolic MRI is a powerful new molecular imaging modality, and parahydrogen-based SABRE technology presents a promising approach to hyperpolarize metabolites with high throughput, low cost, and minimal methodological and instrumental burden. In the Concept Article by Andreas B. Schmidt, Stephan Knecht, and co-workers key advances are reviewed that have recently enabled the first in vivo metabolic imaging with hyperpolarized pyruvate using SABRE.

Biosensors are analytical tools that integrate a biological element with a physicochemical detector in order to quantify the existence or concentration of chemicals, biomolecules, or other biological elements for human health monitoring purposes. Electrochemical techniques for biological analyte detection include the use of electrochemical sensors to identify and quantify the existence and concentration of biological molecules. These techniques are often used because of their high sensitivity, specificity, quick reaction time, and the possibility of being made smaller in size, but still, the research problem in electrochemical-based biosensing largely revolves around improving biosensors′ sensitivity, selectivity, stability, and response time. Borophene, an intriguing and novel substance within the domain of two-dimensional (2D) materials, emerges as a highly promising protagonist in the continuous and dynamic history of nanoscience and nanotechnology. Borophene, characterized by its distinctive electronic, mechanical, and thermal properties, enthralls scientists due to its atomic structure consisting exclusively of boron atoms organized in a honeycomb lattice. In recent years, borophene hybrids and composites have emerged as potentially fruitful avenues for expanding their utility in numerous fields and improving their properties. In addition, borophene and its hybrid systems hold significant potential to overcome the limitations of current electrochemical-based biosensors. By leveraging their unique properties—such as high surface area, chemical versatility, and mechanical strength—these materials can improve biosensors′ limitations. Moreover, the integration of borophene with other materials can further optimize performance, paving the way for advanced and practical biosensing solutions. This perspective presents a synopsis of recent developments in biosensing composites and hybrids based on borophene, including polymers and other nanomaterials. In addition, we emphasized the remarkable characteristics of borophene hybrids, which permit the detection of biological analytes such as proteins, nucleic acids, and small molecules in a sensitive and selective manner. Additionally, a summary of the computational investigations into analyte detection utilizing borophene-based systems has been provided. In a nutshell, we discussed the challenges and future directions in the field, outlining opportunities for further innovation and optimization of borophene-based biosensing platforms.

Hyperpolarized magnetic resonance imaging (HP-MRI) has emerged as a powerful tool in molecular imaging, providing in vivo, real-time insights into metabolic pathways without ionizing radiation. Signal Amplification by Reversible Exchange (SABRE) represents a promising hyperpolarization technique, leveraging parahydrogen to enhance MRI signals. In this concept, we delineate the evolution of SABRE and landmark papers that have enabled us recently to produce biocompatible and low-cost hyperpolarized pyruvate within minutes for in vivo metabolic imaging, showcasing SABRE′s potential for preclinical and near-future clinical settings. Looking ahead, with ongoing efforts focused on optimizing polarizer technology and expanding applications beyond pyruvate, we envision SABRE as a key player in the research and application of HP-MRI due to its simplicity and throughput.

The expression profiles of intracellular biomarkers hold significance for understanding cellular biological functions and tracking pathological activities. Due to its programmability and biocompatibility, extensive efforts have been devoted to design various kinds of nucleic acid probes for biomarker detection. However, pinpointing a single biomarker could end up in a false positive signal, delaying diagnosis. In this review, we present an overview of current advances in biomarker detection and signal amplification techniques. We highlight strategies for biomarker multiplexing and signal amplification with combination of isothermal approaches. High specificity and sensitivity are the two criteria for a desired probe, as are the challenges encountered by a probe that operates efficiently in biological systems. With higher biomarker identification accuracy, we may be able to move one step closer to precision medicine.

Acetylene (C₂H₂), as an important characteristic gas in transformer fault diagnosis, should be accurately detected and effectively distinguished from other dissolved gases (H₂, CH₄, C₂H₆, C₂H₄, CO, CO₂), which is crucial to determine whether the fault occurs and the fault type, but also faces challenges now. The rational design and employment of rare earth and noble metals are expected to address this issue. In this work, SnO₂-3 at% Sm₂O₃-1 at% PdO based MEMS gas sensor was prepared to achieve high performance detection of C₂H₂ which has a response value of 56 to 50 ppm C₂H₂, response/recovery time of 2 s/136 s, lower detection limit of 1 ppm, power consumption of 15.5 mW, and weak cross sensitivity to other transformer fault characteristic gases. Lewis acids and bases theory was used to explain the reason why rare earth Sm is a benefit element to improve selectivity to C₂H₂. The formation of oxygen vacancies and hetero junctions was used to explain the increased sensitivity of the material. This study proved the feasibility of rare earth and noble metals as potential additives to enable advanced gas-sensitive materials for highly selective transformer fault characteristic gas C₂H₂ detection.

Metronidazole and nimorazole are antibiotics of a nitroimidazole group which also may be potentially utilized as hypoxia radiosensitizers for the treatment of cancerous tumors. Hyperpolarization of ¹⁵N nuclei in these compounds using SABRE-SHEATH (Signal Amplification By Reversible Exchange in SHield Enables Alignment Transfer to Heteronuclei) approach provides dramatic enhancement of detection sensitivity of these analytes using magnetic resonance spectroscopy and imaging. Methanol-d₄ is conventionally employed as a solvent in SABRE hyperpolarization process. Herein, we investigate SABRE-SHEATH hyperpolarization of isotopically labeled [¹⁵N₃]metronidazole and [¹⁵N₃]nimorazole in nondeuterated methanol and ethanol solvents. Optimization of such hyperpolarization parameters as polarization transfer magnetic field, temperature, parahydrogen flow rate and pressure allowed us to obtain an average ¹⁵N polarization of up to 7.2–7.4 % for both substrates. The highest ¹⁵N polarizations were observed in methanol-d₄ for [¹⁵N₃]metronidazole and in ethanol for [¹⁵N₃]nimorazole. At a clinically relevant magnetic field of 1.4 T the ¹⁵N nuclei of these substrates possess long characteristic hyperpolarization lifetimes (T₁) of ca. 1 to ca. 7 min. This study represents a major step toward SABRE in more biocompatible solvents, such as ethanol, and also paves the way for future utilization of these hyperpolarized nitroimidazoles as molecular contrast agents for MRI visualization of tumors.

Sensitive and accurate detection of small molecules from complex matrix has aroused increasing interest in many fields, yet remains an open challenge. Recent years have witnessed a considerable advance of aptasensors for diagnostic assay development towards diverse small molecules because aptamer is one of the most powerful classes of molecular receptors with advanced affinity and specificity. Herein, we reviewed the small-molecule aptasensors in the past five years, focusing on the principles to specific applications in clinical diagnosis, food safety, and environmental monitoring. The first introductory section on the development of aptasensors in historical view and its analytical features contextualizes essential health-related small molecules. The second part highlights the basic components of aptasensor and the detection principles of different sensors based on signal output modes. The subsequent part systematically discusses various small-molecule sensing platforms by interfacing aptamers with diverse signal amplification strategies. Finally, challenges and perspectives for improving the aptasensor performance are also discussed. By describing biochemical and analytical procedures, this review highlights the optimal use of aptamers in the detection, quantification, and imaging of important health-related small molecules and presents new insights, technical advances, and engineering strategies for practical applications.

Electrochemical impedance spectroscopy (EIS) is a suitable analytical technique to detect interfacial phenomena and analyte binding at electrode surfaces. In contrast to metallic electrodes, carbon-based electrodes are more suited due to the low cost and the availability of more versatile methods for chemical functionalization. For (bio) sensing, often the Faradaic version of EIS in a three-electrode configuration is used, where a redox-active species is used as a marker. In order to avoid interference due to the redox-active marker with the interfacial interaction, we focus here on the use of non-Faradaic EIS in the absence of any added markers. First, we utilize the sedimentation of silica beads as a model system, which reduces the complexity of the interaction simplifying the interpretation of the measured signals. Moreover, we introduce two improvements. First, impedance measurements are performed in a three-electrode configuration with applied potential as an additional variable, which serves as a handle to optimize the sensitivity. Secondly, we present a time-differential strategy to detect subtle changes and demonstrate that we can consistently follow the sedimentation of beads using the non-Faradaic impedance as a function of the applied potential. Finally, we show a proof-of-principle demonstration for the biosensing of cell attachment on the electrodes in real-time using the proposed technique.