Indicator displacement assays (IDAs) offer a unique and innovative approach to molecular sensing. IDAs can facilitate the detection of a range of biologically/environmentally important species, ...provide a method for the detection of complex analytes or for the determination and discrimination of unknown sample mixtures. These attributes often cannot be achieved by traditional molecular sensors
i.e.
reaction-based sensors/chemosensors. The IDA pioneers Inouye, Shinkai, and Anslyn inspired researchers worldwide to develop various extensions of this idea. Since their early work, the field of indicator displacement assays has expanded to include: enantioselective indicator displacement assays (eIDAs), fluorescent indicator displacement assays (FIDAs), reaction-based indicator displacement assays (RIAs), DimerDye disassembly assays (DDAs), intramolecular indicator displacement assays (IIDAs), allosteric indicator displacement assay (AIDAs), mechanically controlled indicator displacement assays (MC-IDAs), and quencher displacement assays (QDAs). The simplicity of these IDAs, coupled with low cost, high sensitivity, and ability to carry out high-throughput automation analysis (
i.e.
, sensing arrays) has led to their ubiquitous use in molecular sensing, alongside the other common approaches such as reaction-based sensors and chemosensors. In this review, we highlight the various design strategies that have been used to develop an IDA, including the design strategies for the newly reported extensions to these systems. To achieve this, we have divided this review into sections based on the target analyte, the importance of each analyte and then the reported IDA system is discussed. In addition, each section includes details on the benefit of the IDAs and perceived limitations for each system. We conclude this Tutorial Review by highlighting the current challenges associated with the development of new IDAs and suggest potential future avenues of research.
Indicator displacement assays (IDAs) offer a unique and innovative approach to molecular sensing. This Tutorial review discusses the basic concepts of each IDA strategy and illustrates their use in sensing applications.
The authors examine issues related to glucose sensing in supramolecular chemistry. Topics discussed include surfaces for sensing applications and polymers for sensing applications.
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The microenvironment (local environment), including viscosity, temperature, polarity, hypoxia, and acidic-basic status (pH), plays indispensable roles in cellular processes. Significantly, organelles ...require an appropriate microenvironment to perform their specific physiological functions, and disruption of the microenvironmental homeostasis could lead to malfunctions of organelles, resulting in disorder and disease development. Consequently, monitoring the microenvironment within specific organelles is vital to understand organelle-related physiopathology. Over the past few years, many fluorescent probes have been developed to help reveal variations in the microenvironment within specific cellular regions. Given that a comprehensive understanding of the microenvironment in a particular cellular region is of great significance for further exploration of life events, a thorough summary of this topic is urgently required. However, there has not been a comprehensive and critical review published recently on small-molecule fluorescent chemosensors for the cellular microenvironment. With this review, we summarize the recent progress since 2015 towards small-molecule based fluorescent probes for imaging the microenvironment within specific cellular regions, including the mitochondria, lysosomes, lipid drops, endoplasmic reticulum, golgi, nucleus, cytoplasmic matrix and cell membrane. Further classifications at the suborganelle level, according to detection of microenvironmental factors by probes, including polarity, viscosity, temperature, pH and hypoxia, are presented. Notably, in each category, design principles, chemical synthesis, recognition mechanism, fluorescent signals, and bio-imaging applications are summarized and compared. In addition, the limitations of the current microenvironment-sensitive probes are analyzed and the prospects for future developments are outlined. In a nutshell, this review comprehensively summarizes and highlights recent progress towards small molecule based fluorescent probes for sensing and imaging the microenvironment within specific cellular regions since 2015. We anticipate that this summary will facilitate a deeper understanding of the topic and encourage research directed towards the development of probes for the detection of cellular microenvironments.
This review comprehensively summarizes and highlights recent progresses in the design and application of small molecule based fluorescent probes for sensing and imaging the microenvironment within specific cellular regions since 2015.
In this tutorial review, we will explore recent advances for the design, construction and application of two-photon excited fluorescence (TPEF)-based small-molecule probes. The advantages of ...TPEF-based probes include deep tissue penetration and minimal photo-damage. We discuss the underlying two-photon (TP) fluorophores including hemicyanine and design strategies such as Förster resonance energy transfer (FRET). Moreover, we emphasize applications for the detection or imaging of cations, anions, small neutral molecules, biomacromolecules, cellular microenvironments, subcellular localization and dual-responsive systems. Examples of photodynamic therapy (PDT) using TP irradiation are also illustrated.
In this tutorial review, we will explore recent advances for the design, construction and application of two-photon excited fluorescence (TPEF)-based small-molecule probes.
Small-molecule based fluorescent probes are increasingly important for the detection and imaging of biological signaling molecules due to their simplicity, high selectivity and sensitivity, whilst ...being non-invasive, and suitable for real-time analysis of living systems. With this perspective we highlight sensing mechanisms including Förster resonance energy transfer (FRET), intramolecular charge transfer (ICT), photoinduced electron transfer (PeT), excited state intramolecular proton transfer (ESIPT), aggregation induced emission (AIE) and multiple modality fluorescence approaches including dual/triple sensing mechanisms (DSM or TSM). Throughout the perspective we highlight the remaining challenges and suggest potential directions for development towards improved small-molecule fluorescent probes suitable for biosensing.
Small-molecule based fluorescent probes are increasingly important for the detection and imaging of biological signaling molecules due to their simplicity, high selectivity and sensitivity, whilst being non-invasive, and suitable for real-time analysis of living systems.
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Conspectus This Account describes a range of strategies for the development of fluorescent probes for detecting reactive oxygen species (ROS), reactive nitrogen species (RNS), and reactive ...(redox-active) sulfur species (RSS). Many ROS/RNS have been implicated in pathological processes such as Alzheimer’s disease, cancer, diabetes mellitus, cardiovascular disease, and aging, while many RSS play important roles in maintaining redox homeostasis, serving as antioxidants and acting as free radical scavengers. Fluorescence-based systems have emerged as one of the best ways to monitor the concentrations and locations of these often very short lived species. Because of the high levels of sensitivity and in particular their ability to be used for temporal and spatial sampling for in vivo imaging applications. As a direct result, there has been a huge surge in the development of fluorescent probes for sensitive and selective detection of ROS, RNS, and RSS within cellular environments. However, cellular environments are extremely complex, often with more than one species involved in a given biochemical process. As a result, there has been a rise in the development of dual-responsive fluorescent probes (AND-logic probes) that can monitor the presence of more than one species in a biological environment. Our aim with this Account is to introduce the fluorescent probes that we have developed for in vitro and in vivo measurement of ROS, RNS, and RSS. Fluorescence-based sensing mechanisms used in the construction of the probes include photoinduced electron transfer, intramolecular charge transfer, excited-state intramolecular proton transfer (ESIPT), and fluorescence resonance energy transfer. In particular, probes for hydrogen peroxide, hypochlorous acid, superoxide, peroxynitrite, glutathione, cysteine, homocysteine, and hydrogen sulfide are discussed. In addition, we describe the development of AND-logic-based systems capable of detecting two species, such as peroxynitrite and glutathione. One of the most interesting advances contained in this Account is our extension of indicator displacement assays (IDAs) to reaction-based indicator displacement assays (RIAs). In an IDA system, an indicator is allowed to bind reversibly to a receptor. Then a competitive analyte is introduced into the system, resulting in displacement of the indicator from the host, which in turn modulates the optical signal. With an RIA-based system, the indicator is cleaved from a preformed receptor–indicator complex rather than being displaced by the analyte. Nevertheless, without a doubt the most significant result contained in this Account is the use of an ESIPT-based probe for the simultaneous sensing of fibrous proteins/peptides AND environmental ROS/RNS.
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In this tutorial review, we will explore recent advances in the construction and application of Förster resonance energy transfer (FRET)-based small-molecule fluorescent probes. The advantages of ...FRET-based fluorescent probes include: a large Stokes shift, ratiometric sensing and dual/multi-analyte responsive systems. We discuss the underlying energy donor-acceptor dye combinations and emphasise their applications for the detection or imaging of cations, anions, small neutral molecules, biomacromolecules, cellular microenvionments and dual/multi-analyte responsive systems.
In this tutorial review, we will explore recent advances in the construction and application of Förster resonance energy transfer (FRET)-based small-molecule fluorescent probes.
In this review we will explore recent advances in the design and application of excited-state intramolecular proton-transfer (ESIPT) based fluorescent probes. Fluorescence based sensors and imaging ...agents (probes) are important in biology, physiology, pharmacology, and environmental science for the selective detection of biologically and/or environmentally important species. The development of ESIPT-based fluorescence probes is particularly attractive due to their unique properties, which include a large Stokes shift, environmental sensitivity and potential for ratiometric sensing.
We review recent advances in the design and application of excited-state intramolecular proton-transfer (ESIPT) based fluorescent probes. These sensors and imaging agents (probes) are important in biology, physiology, pharmacology, and environmental science.
Oxidative stress is closely related to the physiopathology of numerous diseases. Reactive oxygen species (ROS), reactive nitrogen species (RNS), and reactive sulfur species (RSS) are direct ...participants and important biomarkers of oxidative stress. A comprehensive understanding of their changes can help us evaluate disease pathogenesis and progression and facilitate early diagnosis and drug development. In recent years, fluorescent probes have been developed for real-time monitoring of ROS, RNS and RSS levels
in vitro
and
in vivo
. In this review, conventional design strategies of fluorescent probes for ROS, RNS, and RSS detection are discussed from three aspects: fluorophores, linkers, and recognition groups. We introduce representative fluorescent probes for ROS, RNS, and RSS detection in cells, physiological/pathological processes (
e.g.
, Inflammation, Drug Induced Organ Injury and Ischemia/Reperfusion Injury
etc.
), and specific diseases (
e.g.
, neurodegenerative diseases, epilepsy, depression, diabetes and cancer,
etc.
). We then highlight the achievements, current challenges, and prospects for fluorescent probes in the pathophysiology of oxidative stress-related diseases.
Oxidative stress is closely related to the physiopathology of numerous diseases. Reactive oxygen species (ROS), reactive nitrogen species (RNS), and reactive sulfur species (RSS) are direct participants and important biomarkers of oxidative stress.
Multiple enzyme‐driven biological catalytic cascades occur in living organisms, guiding highly efficient and selective transformations of substrates. Inspired by the merits of these biological ...catalytic cascade systems, enormous efforts have been devoted to developing novel cascade catalytic systems to mimic biological cascade catalytic reactions over the past few years. Nanozymes, a class of enzyme mimics, are nanomaterials with enzyme‐like catalytic activity. The emergence and development of nanozymes has significantly advanced the development of biomimetic cascade nanoreactors. Currently, biomimetic cascade nanoreactors driven by advanced nanozymes have been widely used and exhibit many advantages such as superior cascade catalytic efficiency and high stability, resulting in significant advancements in biosensing and biomedical applications. The latest advances in understanding the cascade catalytic mechanism of nanozyme‐engineered biomimetic cascade catalytic nanoreactors and their progressive applications for biosensing and biomedical applications are comprehensively covered here. First, nanozyme and enzyme/nanozyme‐engineered biomimetic cascade catalytic nanoreactors are categorized according to their catalytic mechanism and properties. Then, the biosensing and biomedical applications, including cancer therapy, antibacterial activity, antioxidation, and hyperuricemia therapy of the cascade catalytic systems are covered. The conclusion describes the most important challenges and opportunities remaining in this exciting area of research.
The latest research advances in the construction and cascade catalytic mechanism of enzyme mimics for engineered biomimetic cascade catalytic nanoreactors and their progressive applications in the field of biosensing and for biomedical applications are comprehensively summarized. In addition, the most important challenges and opportunities remaining in this exciting area of research are highlighted.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK