Analysis & sensing最新文献

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.

Metal-organic frameworks (MOFs) are formed by the self-assembly of metal centres/clusters and organic ligands. A diverse range of organic ligands can be employed, including nucleobases, amino acids, peptides, proteins, and saccharides et al. Due to the characteristics of large surface area, high porosity, easy surface functionalization and adjustable internal pore size, et al. MOFs have been used as a significant emerging class of biological imaging agents and have attracted great research interest in optical imaging (OI), photoacoustic imaging (PAI), magnetic resonance imaging (MRI), computer tomography (CT) and positron emission tomography (PET) in recent years. This review provides a comprehensive overview of the diverse range of organic ligands utilized in Metal-organic frameworks, while also delving into the recent advancements, opportunities, and challenges encountered in the realm of bioimaging in recent years.

Nanozymes are a type of artificial enzyme that possess both the unique properties and catalytic activities of nanomaterials. With the rapid development of nanotechnology and biomedicine, nanozymes provide potential opportunities for biomedical applications. In particular, nanozymes, combined with their unique physicochemical performance and enzymatic activity, have been extensively used for in vitro sensing and in vivo imaging. In this review, we systematically summarized the progress of nanozymes and their applications in in vivo imaging and finally proposed the challenges and prospects in the development of nanozymes in biomedical imaging.

Synthetic anion transporters are developed to transport anions across lipid membranes with the long-term perspective of biological applications. The lucigenin assay is a popular tool to study their transport of chloride and other anions in liposomes. It relies on the quenching of the fluorescence of encapsulated lucigenin by anions, which can be monitored by fluorescence spectroscopy. This article provides a tutorial introduction to the practical use and understanding of the lucigenin assay. It describes in detail how to use this assay to monitor chloride/nitrate antiport in liposomes, process and interpret the data, and solve common issues. Variations of the assay enabling the investigation of the transport of other anions and transport mechanisms are discussed. Furthermore, a zwitterionic analogue of lucigenin is demonstrated to have advantages for use in experiments over longer time scales, as it does not leak out of the liposomes, or when studying chloride uniport, as it avoids interference from antiport with nitrate that is present in commercial lucigenin.

Persistent luminescent nanoparticles (PLNP) have outstanding advantages in low-background imaging. However, avoiding exogenous interference and false positive signals to achieve precise imaging is still a problem. In addition, it is also a great challenge to intelligently control the size of PLNP. Herein, we report an intelligent luminescence ratiometric sensor based on ultra-small dual-emissive PLNP for precise tumor-targeted imaging. ZnGa₂O₄:Cr PLNP with a particle size of c.a. 5–10 nm and two emission peaks at 708 nm and 501 nm were firstly synthesized by thermal decomposition method along with systematical controlling the amount of chromium. [email protected] sensor was further constructed with a constant ratio (I₇₀₈/I₅₀₁) which is not interfered by exogenous factors such as detection time window and probe concentration. However, high concentrations of glutathione in the tumor microenvironment can specifically trigger the change of I₇₀₈/I₅₀₁ and cause the sensor to self-assemble into clusters at tumor site, thus realizing long-term retention and specificity imaging.

Stimuli-triggered in-situ morphological transformation of peptide nanomaterials may enhance the on-site accumulation and retention of the imaging agent cargos in the stimuli-rich regions, thus enabling precise, sensitive, and prolonged imaging of diseases. Moreover, this strategy permits the co-delivery of contrast agents and drugs with the smart “turn-on” ability, allowing for efficient disease theranostics. In light of the significance of this strategy in designing smart biomedical peptide materials, which remains scarcely reviewed in recent years, we herein provide this review. We summarize the bioimaging applications (i. e., fluorescence imaging, magnetic resonance imaging, and photoacoustic imaging) of these smart morphological transformation-based peptide materials, and highlight the remarkable breakthroughs. Besides, challenges to be addressed in this field are discussed.

Fluorescent probes are valuable tools to visualize non-catalytic proteins in live cells. Currently, the majority of imaging reagents for non-catalytic proteins are based on “always-on” fluorophores and the use of these reagents usually necessitate a wash step to remove unbounded fluorophores before microscope imaging. Herein, we report the use of arylamino-substituted rhodamine as an activatable fluorophore for the imaging of non-catalytic protein in live cells. We have shown the induction of an arylamino to structurally rigid rhodamine could significantly reduce the fluorescent emission in aqueous medium but the ligand-directed binding of this molecule to protein receptor could effective restrict its intramolecular motion and thus lead to enhancement in fluorescence intensity at 590 nm over 30-fold. With fluorescent probes based on this fluorophore, we could visualize integrin α_vβ₃ and azido-functionalized glycans in living cells with high contrast in a wash-free manner.

The use of nanoprobes has revolutionized the way we approach medical diagnosis and treatment. These tiny particles are designed to target specific cells or tissues within the body, allowing doctors to visualize and monitor disease progression in real-time. The paramount consideration in the utilization of nanoprobes is their safety. Unlike traditional contrast agents, which can cause adverse reactions in some patients, these probes are specifically engineered to minimize any potential harm. And it can promote the rapid development of new biological imaging techniques in various fields such as biological structure and functional imaging, disease diagnosis, in situ imaging, and real-time dynamic imaging at the in vivo level. Based on the principles and mechanisms of imaging, this study focuses on the recent applications of nanoprobes for several typical imaging techniques (magnetic resonance imaging, computed tomography imaging, fluorescence imaging, and acoustic imaging) with the aim of providing researchers with a fresh perspective on precise disease diagnosis and treatment through the development of nanoprobes.

Myeloperoxidase (MPO) is a mammalian pro-oxidant protease and it is closely related to severe infections and diverse inflammatory diseases. Rapid and sensitive measurement of MPO activity is essential for anticancer drug discovery and inflammatory research. Herein, we demonstrate the construction of an oxidative cleavage-activated deoxyribozymes (DNAzyme) biosensor for rapid detection and cellular imaging of the MPO activity. When target MPO is present, the phosphorothioate (PS)-modified hairpin probe is site-specifically cleaved by MPO, releasing the intact Mg²⁺-dependent DNAzyme sequences. Subsequently, the activated DNAzyme initiates the cyclic cleavage of the signal probe with the assistance of cofactor Mg²⁺, liberating large numbers of Cy5 molecules. This assay possesses the characteristics of easy operation, low sample consumption, without the requirements of expensive radiolabeling, antibodies, and nanomaterials. Especially, this assay can be performed in one pot under isothermal conditions (37°C) within 60 min. Due to the high efficiency of DNAzyme-based cyclic cleavage reaction and the intrinsic advantages of single-molecule detection, this assay achieves high sensitivity with a limit of detection (LOD) of 2.74×10⁻³ ng μL⁻¹. It can be applied to screen MPO inhibitors, measure cellular MPO activity at the single-cell level, and image intracellular MPO in living cells, providing a powerful platform for early clinical diagnosis and drug discovery.