Analysis & sensing最新文献

Metal-organic frameworks (MOFs) offer an impeccable platform for glucose sensing, contributing in both enzymatic- and non-enzymatic-based electrochemical detection. Comprising metal ions and organic ligands, MOFs with their exceptional properties including tunable porosity, high surface area, diverse structural configuration, strong adsorptive capacity, electrocatalytic behavior, and abundant active sites pave way for improving healthcare diagnostics. More in the Review by R. Ajay Rakkesh and co-workers.

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.

Effective glucose monitoring is critical for managing diabetes and preventing its associated complications. While commercial glucose monitoring devices predominantly rely on blood samples, emerging research focuses on detecting glucose in alternative biofluids, harnessing advanced nanomaterials. Among these, Metal-Organic Frameworks (MOFs), composed of metal ions and organic ligands, have garnered significant attention due to their unique properties, including tunable porosity, high surface area, and abundant active sites conducive to glucose interaction. MOFs present a versatile platform for glucose sensing, offering potential in both enzymatic and non-enzymatic detection methods. This review delves into the recent advancements in MOFs-based electrochemical glucose sensors, providing a comprehensive analysis of various MOFs and their composites as electrode materials. The discussion highlights the structural attributes, functionalization strategies, and electrochemical performance of MOFs in glucose sensing, emphasizing their role in the development of next-generation, non-invasive glucose monitoring technologies. The review provides a comprehensive overview on the application of MOFs and MOFs-based composites in both enzymatic and non-enzymatic electrochemical-based glucose sensing and highlights the synthesis, mechanism, functionalization and development in the detection strategy of MOFs in glucose sensing.

Flexible biosensors play a crucial role for healthcare management and disease diagnosis. Electrochemical biosensors have attracted significant attention for wearable sensing applications owing to their numerous advantages, including high sensitivity and selectivity, inherent miniaturization and rapid response times. Challenges lie in the development of highly conductive and flexible electrodes that can be integrated with biorecognition components to engineer selective biosensor interfaces. Carbon nanotubes (CNTs) hold significant promise as materials for wearable flexible sensor fabrication. This review highlights recent strategies for fabricating conductive and flexible electrodes, whether in the form of films or fibers, based on CNTs and their composites. Additionally, the review explores emerging biosensing applications, including flexible sensors for the direct electrochemical detection of biomarkers, sensors functionalized with enzymes, antibodies, or DNA, and sensors interfaced with cells to monitor transient biochemical signals.

Formic acid (FA) is one of the very important organic acids that has been widely used in various industries. The highly corrosive FA can have severe adverse effects on the surrounding environment. Here, we developed an electrochemical sensor that utilizes the material properties of multi-walled carbon nanotubes (MWCNTs), and copper phthalocyanine (CuPc) for the real-time detection of FA gas. The response of FA has been compared with the responses of 9 common volatile organic compounds (VOCs). The chronoamperometry (CA) results revealed a high selectivity towards FA by showing an increase in the sensor current by about 25 %, in contrast to the decrease of the current in response to the other VOCs. The sensitivity of the CuPc device to FA was calculated to be 38.85 mAM⁻¹. Material characterization (SEM, EDX, FTIR, Raman, and UV-vis) also strongly suggests a protonation mechanism caused by the carboxylic acid group, which enhances the electrical conductivity.

At present, two competing hyperpolarization (HP) techniques, dissolution dynamic nuclear polarization (DNP) and parahydrogen (para-H₂) induced polarization (PHIP), can generate sufficiently high liquid state ¹³C signal enhancement for in vivo studies. PHIP utilizes the singlet spin state of para-H₂ to create non-equilibrium spin populations. In hydrogenative PHIP, para-H₂ is irreversibly added to unsaturated precursors, typically in the presence of a homogeneous catalyst. The hydrogenation catalyst plays a crucial role in converting the singlet spin order of para-H₂ into detectable nuclear polarization. Currently, rhodium(I) bisphosphine complexes are the most widely employed catalysts for PHIP, capable of catalyzing the addition of para-H₂ to unsaturated precursors in organic solvents or aqueous media, depending on the ligand. Chiral catalysts enable the stereoselective production of hyperpolarized substrates. Ruthenium(II) piano stool complexes are capable of trans addition and are used to generate hyperpolarized fumarate. However, these catalysts systems are not optimal, and the greatest source of nuclear spin polarization loss is attributed to the mixing of singlet and triplet states of the protons derived from the para-H₂ during the hydrogenation process. Hence, future efforts should focus on enhancing the efficiency and kinetics of these catalysts.

Carbon nano-onions (CNOs) promise to improve the range of applications of carbon materials for electroanalytical applications. In this review, we explore the synthesis, characterization, and electrochemical applications of CNOs. CNO-based sensors present impressive features, including low detection limits in the femtogram per milliliter range, a broad linear detection range spanning up to 7 orders of magnitude, exceptional selectivity, reproducibility, and stability. Synthetic methods and characterization techniques for CNOs were thoroughly examined, shedding light on their pivotal role in biosensing technologies. Comparative analyses with other carbon materials underscore CNOs′ competitive performance, either surpassing or matching many counterparts. Despite their relatively recent integration in biosensing applications, CNOs exhibit comparable or superior results concerning other carbon-based materials. Indeed, the incorporation of CNOs into hybrid nanocomposites has shown promising outcomes, indicating a synergistic potential for future advancements in biosensing technologies. Our review provides a broad approach to the application of CNOs to the field, with emphasis on breakthroughs of the last 5 years.

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.

Here we report a robust G-quadruplex (G4) dimer-guided transmembrane DNA nanovehicle for targeted payload delivery, based on dimeric G4-proximized aptamers that efficiently target transferrin receptors (TfR) over-expressed on cancer cell surface. It enables the cancer-specific delivery of fluorescent G4 ligands and therapeutic drugs for cellular imaging and treatment.