Analysis & sensing最新文献

The ability to monitor protein biomarkers at clinically relevant concentrations is a powerful approach that provides insights into health status. The synergistic combination of microfluidics and photonics (optofluidic) has emerged as a new means to achieve this capability for detection and manipulation of biological samples. Here in this work, we demonstrate an optofluidic device which integrates the detection and the particle-focusing components to facilitate on-chip measurement of protein levels. With this design, we use a laser-induced fluorescence technique for the direct measurement of protein levels on magnetic bead complexes tagged with fluorescein isothiocyanate (FITC) fluorophore. The developed system was employed for the detection of human immunoglobulin G (IgG) as a model protein within a range of 0–20 μg/mL, showing an ability to resolve the fluorescence signal from different IgG concentrations down to 5.4 nM (0.81 μg/mL). The selectivity in detecting specific IgG target was tested by comparing the fluorescence signal levels from other interfering proteins such as bovine serum albumin (BSA) and human IgM. Although our system was designed for detecting IgG protein, this optofluidic device can be a powerful platform for the rapid detection of a diverse range of biomarkers, including viral pathogens retaining adequate signal sensitivity and selectivity.

Fatty acids (FAs) contain a vast amount of structural diversity, and differences in fatty acid structure have been associated with various disease states. Accurate identification and characterization of fatty acids is critical to fully understand the biochemical roles these compounds play in disease progression. Conventional tandem mass spectrometry (MS/MS) workflows do not provide sufficient structural information, necessitating alternative dissociation methods. Gas-phase charge inversion ion/ion reactions can be used to alter the ion type subjected to activation to provide improved or complementary structural information. Herein, we have used an ion/ion reaction between fatty acid (FA) anions and magnesium tris-phenanthroline [Mg(Phen)₃] dications to promote charge remote fragmentation of carbon-carbon bonds along the fatty acid chain, allowing for localization of carbon-carbon double bond (C=C) positions to successfully differentiate monounsaturated fatty acid isomers. Relative quantification was also performed to obtain the relative abundance of fatty acid isomers in different biological tissues. For example, the relative abundance of FA 18 : 1 (9) was determined to vary across regions of rat brain, rat kidney, and mouse pancreas, and FA 16 : 1 (9) was found to have a higher relative abundance in the dermis layer compared to the sebaceous glands in human skin tissue.

Point-of-care technologies need particularly stringent requirements, including portability, rapidity, affordability, and ease of use, enabling healthcare practitioners to perform reliable analyses in decentralized settings. Such diagnostic tests are usually based on bioassays that allow for the detection of clinically relevant biomarkers, namely proteins, antibodies and nucleic acids. In the context of electrochemical biosensors, the implementation of magnetic beads offers unique advantages stemming from their high surface-to-volume ratio, easy manipulation through magnetic fields and versatility in surface chemistries for bio-conjugation. The present concept article highlights the advantages achieved through the implementation of magnetic beads in electrochemical binding assays, immunosensors and genosensors. These methods mostly exploit magnetic beads for immobilization purposes, allowing for the assembly of bio-complexes in liquid suspensions under precise temperature and shaking control, as well as simplifying the manipulation steps to enable untrained personnel to perform analyses. In addition, magnetic beads can also take part in the detection mechanism, leading to innovative sensing strategies with great potential for point-of-care diagnostic applications.

The cover feature illustrates the application of high-brightness green fluorescent polymer dots (Pdots) to intraoperative neuroimaging to achieve excellent tracing effects. Through direct administration, Pdots can rapidly bind to the epineurium and perineurium, stably characterizing the peripheral nerve. In addition, it was found that Pdots bind to nerve membranes, do not invade nerve cells, and have high biosafety. Our study illustrates that Pdots has the potential as a neurotracer in image-guided surgery and has significant implications for reducing iatrogenic nerve injury and related surgical complications. More information can be found in the Research Article by Liqin Xiong and co-workers.

The front cover image illustrates the selective illumination of lipid droplets by BODIPYs, effectively highlighting the trafficking of lipid droplets between neighbouring cells. Two asymmetric BODIPY derivatives, exhibiting a red-shifted emission spectrum and a substantial Stokes shift compared to reference compounds, were successfully synthesized. These favourable fluorescence characteristics enabled the application of these derivatives in probing the influence of starvation on the intercellular exchange of lipid droplets. More information can be found in the Research Article by Amandeep Kaur, Elizabeth J. New, and co-workers.

Over the past few decades, pretargeted bioimaging has made significant contributions to disease diagnosis and the real-time visualization of biological processes. Notably, the inverse electron demand Diels-Alder (IEDDA) reaction between tetrazine (Tz) and trans-cyclooctene (TCO) has shown enormous potential in pretargeted bioimaging applications by capitalizing on its rapid kinetics, specific reactivity, biorthogonality and biocompatibility. To date, imaging probes based on the Tz−TCO click reaction have been extensively developed and widely used for pretargeted bioimaging applications. In this review, we focus on the Tz−TCO click reaction and summarize its applications in pretargeted bioimaging. Firstly, the fundamental principles for designing imaging probes based on the Tz−TCO click reaction are explained. Then, recent advances in imaging probes based on the Tz−TCO click reaction are discussed in detail. Finally, the current challenges and perspectives of the Tz−TCO click reaction in pretargeted bioimaging applications are presented.

The simultaneous detection of multiple analytes using electrochemical biosensor arrays has demonstrated significant potential in various fields, including medical diagnostics. These platforms are designed to be low-cost, easy to use, and offer fast detection of a range of molecules. This concept article discusses the components necessary to achieve multiplexing with electrochemical biosensor arrays. The various methods used to fabricate electrode arrays of different types are discussed. Furthermore, the methods for the selective immobilization of multiple different bioreceptors onto individual electrodes within the array, a crucial step essential for conferring specificity to the analytical processes, are presented with relevant examples. We have focused on enzymes, antibodies and aptamers as examples of bioreceptors that have been deployed in various multianalyte electrochemical detection platforms. Finally, we discuss the key challenges associated with their application for the analysis of real samples and provide a future outlook on possible strategies that can be used to overcome these challenges.

The skeleton plays a significant role in human health. Comprehensive and non-invasive visualization of the bone is in high demand to detect bone-related diseases. Clinically, conventional imaging techniques continue to face challenges in terms of limited imaging sensitivity, extended acquisition durations, and the inherent presence of ionizing radiation. These factors collectively hinder their capacity to furnish real-time spatial insights into cellular activity. Recently, Numerous innovative imaging methodologies employing diverse types of probes have emerged to enhance the clinical detection of bone. In vivo imaging of bone contribute to continuously detecting bone metabolism and growth, diagnosing bone metastases, visualizing medication delivery to bones. Fluorescent probes in dynamic detection of bone metabolism several inherent advantages. First, Fluorescent probes present lower potential long-term toxicity than radioactive isotope labels. Second, fluorescent dyes used in in vitro imaging are more cost-effective and come in a more compact size. Next, Near-infrared (NIR) dyes have deeper tissue penetration capability and lower tissue autofluorescence. However, bone-imaging fluorescent probes highly depend on phosphonate-related ligands. These ligands have multiple side effects in clinic and long half-live of them also exacerbates clearance concerns. This review aims to conclude and analyse the recently reported fluorescent probes for the precise detection of bone. Firstly, we outline the fundamental design mechanism of bone fluorescent probes and describe diverse bone-targeting moieties, emphasizing the targeting ligands, signal moieties, and functionalities of these probes. Secondly, we discuss the recent promising bone fluorescent probes for the precise and sensitive detection of bone. Finally, we offer our insights on potential future advancements in this field. We anticipate that this review will inspire creative ideas for designing and creating innovative bone-targeting probes, with applications in bone imaging, pharmaceutical screening, and assessing therapeutic outcomes.

Iatrogenic nerve injury is an important cause of surgical complications. We focused on improving intraoperative visualization of nerves through highly fluorescent polymer dots (Pdots) and in vivo optical imaging instrumentation. The prepared Pdots have good biocompatibility, fluorescence stability, and simple preparation. Peripheral nerves can be imaged quickly with Pdots through a simple direct administration method and process, low non-specific absorption in the surrounding tissues. Moreover, the Pdots does not invade nerve cells but binds stably in the neural membrane structure. This study verifies that fluorescent Pdots have excellent neuroimaging capabilities and can be used for intraoperative visualization of peripheral nerves.

Developing a simple, selective, and rapid reliable method to monitor hypochlorous acid (HClO) in vivo is very meaningful due to its important physiological and pathological functions. In this research, a novel AIE based fluorescent probe for ratiometric detection of HClO was fabricated by a simple one-step synthesis, in which the methyl sulfide group and salicylaldehyde azine serve as the recognition unit and fluorophore, respectively. This probe was visible-light-excitable, and showed a palpable aggregation-induced emission into the red region with high stability to Cu²⁺ and pH. Oxidation of the methyl sulfide group can be achieved rapidly and specifically by HClO in physiological condition, which enables it to display a rapid, ratiometric fluorescent response to HClO with high selectivity over other biologically pertinent species. By exploiting the probe-based tool, we successfully validated its practical utility in selectively recognizing HClO in living cells via ratiometric fluorescence signals, thereby providing a potential method for investigating the relevant functions of HClO in biosystems.