Publications by authors named "Steven Bull"

96 Publications

Indicator displacement assays (IDAs): the past, present and future.

Chem Soc Rev 2021 Jan 10;50(1):9-38. Epub 2020 Nov 10.

Department of Chemistry, The University of Texas at Austin, 105 East 24th Street A5300, Austin, Texas 78712-1224, USA.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9cs00538bDOI Listing
January 2021

Antimicrobial innovation: a current update and perspective on the antibiotic drug development pipeline.

Future Med Chem 2020 Nov 10;12(22):2035-2065. Epub 2020 Nov 10.

School of Chemistry, Monash University, Clayton, 3800, Australia.

As bacteria continue to develop resistance to our existing treatment options, antibiotic innovation remains overlooked. If current trends continue, then we could face the stark reality of a postantibiotic era, whereby routine bacterial infections could once again become deadly. In light of a warning signaled by the WHO, a number of new initiatives have been established in the hope of reinvigorating the antibiotic drug development pipeline. In this perspective, we aim to summarize some of these initiatives and funding options, as well as providing an insight into the predicament that we face. Using clinical trials data, company website information and the most recent press releases, a current update of the antibiotic drug development pipeline is also included.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4155/fmc-2020-0225DOI Listing
November 2020

A Photodeactivatable Antagonist for Controlling CREB-Dependent Gene Expression.

ACS Cent Sci 2020 Oct 31;6(10):1813-1818. Epub 2020 Aug 31.

Division of Advanced Science and Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.

A novel photodeactivation strategy for controlling gene expression has been developed based on light-induced activation of cAMP response element binding protein (CREB). Light-induced cleavage of the photoresponsive protecting group of an antagonist of CREB binding protein (CBP) results in photocleaved products with weak binding affinity for CBP. This photodissociation reaction enables protein-protein interactions between CBP and CREB that trigger the formation of a multiprotein transcription complex to turn gene expression "on". This enables irradiation of antagonist-treated HEK293T cells to be used to trigger temporal recovery of CREB-dependent transcriptional activity and endogenous gene expression under photolytic control.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acscentsci.0c00736DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7596873PMC
October 2020

A fluorescent ESIPT-based benzimidazole platform for the ratiometric two-photon imaging of ONOO and .

Chem Sci 2020 Jul 16;11(28):7329-7334. Epub 2020 Jun 16.

Department of Chemistry , University of Bath , BA2 7AY , UK . Email: ; Email:

In this work, we have developed an ESIPT-based benzimidazole platform ( and ) for the two-photon cell imaging of ONOO and a potential ONOO-activated theranostic scaffold (). Each benzimidazole platform, , were shown to rapidly detect ONOO at micromolar concentrations (LoD = 0.28 μM, 6.53 μM and 0.81 μM respectively). The potential theranostic was shown to release the parent fluorophore and drug indomethacin in the presence of ONOO but unfortunately did not perform well due to low solubility. Despite this, the parent scaffold demonstrated its effectiveness as a two-photon imaging tool for the ratiometric detection of endogenous ONOO in RAW264.7 macrophages and rat hippocampus tissue. These results demonstrate the utility of this ESIPT benzimidazole-based platform for theranostic development and bioimaging applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0sc02347gDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7499849PMC
July 2020

An Acid-Activatable Fluorescence Probe for Imaging Osteocytic Bone Resorption Activity in Deep Bone Cavities.

Angew Chem Int Ed Engl 2020 11 8;59(47):20996-21000. Epub 2020 Sep 8.

Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.

A rationally designed pH-activatable fluorescent probe (pHocas-RIS) has been used to measure localised pH levels in osteocytic lacunae in bone tissue. Conjugation of the moderate bone-binding drug risedronate to a pH-activatable BODIPY fluorophore enables the probe to penetrate osteocytic lacunae cavities that are embedded deep within the bone matrix. After injection of pHocas-RIS, any osteocytic lacunae caused by bone-resorbing osteocytes cause the probe to fluoresce in vivo, thus allowing imaging by intravital two-photon excitation microscopy. This pH responsive probe enabled the visualization of the bone mineralizing activities of acid producing osteocytes in real time, thus allowing the study of their central role in remodeling the bone-matrix in healthy and disease states.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.202006388DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7692916PMC
November 2020

Förster resonance energy transfer (FRET)-based small-molecule sensors and imaging agents.

Chem Soc Rev 2020 Aug 22;49(15):5110-5139. Epub 2020 Jul 22.

The Education Ministry Key Laboratory of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, and Shanghai Municipal Education Committee Key Laboratory of Molecular Imaging Probes and Sensors, Department of Chemistry, Shanghai Normal University, 100 Guilin Road, Shanghai 200234, China.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9cs00318eDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7408345PMC
August 2020

Protein Encapsulation: A Nanocarrier Approach to the Fluorescence Imaging of an Enzyme-Based Biomarker.

Front Chem 2020 3;8:389. Epub 2020 Jun 3.

Department of Chemistry, University of Bath, Bath, United Kingdom.

Here, we report a new pentafluoropropanamido rhodamine fluorescent probe (ACS-HNE) that allows for the selective detection of neutrophil elastase (NE). ACS-HNE displayed high sensitivity, with a low limit of detection (<5.3 nM), and excellent selectivity toward elastase over other relevant biological analytes and enzymes. The comparatively poor solubility and cell permeability of neat ACS-HNE was improved by creating an ACS-HNE-albumin complex; this approach allowed for improvements in the visualization of elastase activity in RAW 264.7 cells relative to ACS-HNE alone. The present study thus serves to demonstrate a simple universal strategy that may be used to overcome cell impermeability and solubility limitations, and to prepare probes suitable for the cellular imaging of enzymatic activity .
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fchem.2020.00389DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7283737PMC
June 2020

Sensing Peroxynitrite in Different Organelles of Murine RAW264.7 Macrophages With Coumarin-Based Fluorescent Probes.

Front Chem 2020 20;8:39. Epub 2020 Feb 20.

Department of Chemistry, University of Bath, Bath, United Kingdom.

The elucidation of biological processes involving reactive oxygen species (ROS) facilitates a better understanding of the underlying progression of non-communicable diseases. Fluorescent probes are a powerful tool to study various ROS and have the potential to become essential diagnostic tools. We have developed a series of coumarin fluorescent probes for the selective and sensitive detection of peroxynitrite (ONOO), a key ROS. Coumarin based probes exhibit good photostability, large Stokes shift and high quantum yields. The three ratiometric probes all contain a boronate ester motif for the detection of ONOO and a distinctive organelle targeting group. The study of ONOO generation in a particular organelle will allow more precise disease profiling. Hence, targeting groups for the mitochondria, lysosome and endoplasmic reticulum were introduced into a coumarin scaffold. The three ratiometric probes displayed sensitive and selective detection of ONOO over other ROS species. All three coumarin probes were evaluated in murine RAW264.7 macrophages for detection of basal and stimulated ONOO formation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fchem.2020.00039DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7044669PMC
February 2020

Peroxynitrite Activated Drug Conjugate Systems Based on a Coumarin Scaffold Toward the Application of Theranostics.

Front Chem 2019 5;7:775. Epub 2019 Dec 5.

Department of Chemistry, University of Bath, Bath, United Kingdom.

Two novel drug-conjugates based on a "coumarin linker" have been designed for the synergic release of a therapeutic agent and fluorescent probe for the potential application of theranostics. The drug conjugates; and were designed to be activated by reactive oxygen species or reactive nitrogen species (ROS/RNS). The fluorescence OFF-ON response was triggered by the peroxynitrite-mediated transformation of a boronic acid pinacol ester to a phenol moiety with simultaneous release of the therapeutic agents (Confirmed by HRMS). The limit of detection for peroxynitrite using and was 0.29 and 37.2 μM, respectively. Both and demonstrated the ability to visualize peroxynitrite production thus demonstrating the effectiveness of these probes for use as tools to monitor peroxynitrite-mediated drug release in cancer cell lines.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fchem.2019.00775DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6906548PMC
December 2019

A Simple Near-Infrared Fluorescent Probe for the Detection of Peroxynitrite.

ChemistryOpen 2019 Dec 9;8(12):1407-1409. Epub 2019 Dec 9.

Department of Chemistry University of Bath, BA2 7AY, UK.

Herein, we report the evaluation and synthesis of a reaction based fluorescent probe for the detection of Peroxynitrite (ONOO-). exhibits selective fluorescence off-on response for ONOO over other reactive oxygen species, including HO. Moreover, is biocompatible and has been used to visualize exogenous ONOO in HeLa cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/open.201900301DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6900745PMC
December 2019

Reaction-based indicator displacement assay (RIA) for the development of a triggered release system capable of biofilm inhibition.

Chem Commun (Camb) 2019 Dec;55(100):15129-15132

Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.

Here, a reaction-based indicator displacement hydrogel assay (RIA) was developed for the detection of hydrogen peroxide (H2O2) via the oxidative release of the optical reporter Alizarin Red S (ARS). In the presence of H2O2, the RIA system displayed potent biofilm inhibition for Methicillin-resistant Staphylococcus aureus (MRSA), as shown through an in vitro assay quantifying antimicrobial efficacy. This work demonstrated the potential of H2O2-responsive hydrogels containing a covalently bound diol-based drug for controlled drug release.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9cc07759fDOI Listing
December 2019

A Three-Component Derivatization Protocol for Determining the Enantiopurity of Sulfinamides by H and F NMR Spectroscopy.

J Org Chem 2020 01 16;85(2):1208-1215. Epub 2019 Dec 16.

Department of Chemistry , University of Bath , Claverton Down , Bath , BA2 7AY , U.K.

A practically simple three-component chiral derivatization protocol has been developed to determine the enantiopurity of eight -chiral sulfinamides by H and F NMR spectroscopic analysis, based on their treatment with a 2-formylphenylboronic acid template and enantiopure pinanediol to afford a mixture of diastereomeric sulfiniminoboronate esters whose diastereomeric ratio is an accurate reflection of the enantiopurity of the parent sulfinamide.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.joc.9b02473DOI Listing
January 2020

Azulene-Derived Fluorescent Probe for Bioimaging: Detection of Reactive Oxygen and Nitrogen Species by Two-Photon Microscopy.

J Am Chem Soc 2019 12 27;141(49):19389-19396. Epub 2019 Nov 27.

Department of Chemistry , University of Bath , Bath BA2 7AY , United Kingdom.

Two-photon fluorescence microscopy has become an indispensable technique for cellular imaging. Whereas most two-photon fluorescent probes rely on well-known fluorophores, here we report a new fluorophore for bioimaging, namely azulene. A chemodosimeter, comprising a boronate ester receptor motif conjugated to an appropriately substituted azulene, is shown to be an effective two-photon fluorescent probe for reactive oxygen species, showing good cell penetration, high selectivity for peroxynitrite, no cytotoxicity, and excellent photostability.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jacs.9b09813DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6909233PMC
December 2019

Reaction-Based Fluorescent Probes for the Detection and Imaging of Reactive Oxygen, Nitrogen, and Sulfur Species.

Acc Chem Res 2019 09 28;52(9):2582-2597. Epub 2019 Aug 28.

Department of Chemistry , University of Bath , Bath BA2 7AY , U.K.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.accounts.9b00302DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7007013PMC
September 2019

Long Wavelength TCF-Based Fluorescent Probe for the Detection of Alkaline Phosphatase in Live Cells.

Front Chem 2019 30;7:255. Epub 2019 Apr 30.

Department of Chemistry, University of Bath, Bath, United Kingdom.

A long wavelength TCF-based fluorescent probe () was developed for the detection of alkaline phosphatase (ALP). ALP-mediated hydrolysis of the phosphate group of resulted in a significant fluorescence "turn on" (58-fold), which was accompanied by a colorimetric response from yellow to purple. was cell-permeable, which allowed it to be used to image ALP in HeLa cells. Upon addition of bone morphogenic protein 2, proved capable of imaging endogenously stimulated ALP in myogenic murine C2C12 cells. Overall, TCF-ALP offers promise as an effective fluorescent/colorimetric probe for evaluating phosphatase activity in clinical assays or live cell systems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fchem.2019.00255DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6508040PMC
April 2019

Exposing the Interplay Between Enzyme Turnover, Protein Dynamics, and the Membrane Environment in Monoamine Oxidase B.

Biochemistry 2019 05 23;58(18):2362-2372. Epub 2019 Apr 23.

School of Biochemistry , University of Bristol , Biomedical Sciences Building, University Walk , Bristol BS8 1TD , United Kingdom.

There is an increasing realization that structure-based drug design may show improved success by understanding the ensemble of conformations accessible to an enzyme and how the environment affects this ensemble. Human monoamine oxidase B (MAO-B) catalyzes the oxidation of amines and is inhibited for the treatment of both Parkinson's disease and depression. Despite its clinical importance, its catalytic mechanism remains unclear, and routes to drugging this target would be valuable. Evidence of a radical in either the transition state or the resting state of MAO-B is present throughout the literature and is suggested to be a flavin semiquinone, a tyrosyl radical, or both. Here we see evidence of a resting-state flavin semiquinone, via absorption redox studies and electron paramagnetic resonance, suggesting that the anionic semiquinone is biologically relevant. On the basis of enzyme kinetic studies, enzyme variants, and molecular dynamics simulations, we find evidence for the importance of the membrane environment in mediating the activity of MAO-B and that this mediation is related to the protein dynamics of MAO-B. Further, our MD simulations identify a hitherto undescribed entrance for substrate binding, membrane modulated substrate access, and indications for half-site reactivity: only one active site is accessible to binding at a time. Our study combines both experimental and computational evidence to illustrate the subtle interplay between enzyme activity and protein dynamics and the immediate membrane environment. Understanding key biomedical enzymes to this level of detail will be crucial to inform strategies (and binding sites) for rational drug design for these targets.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.biochem.9b00213DOI Listing
May 2019

Correction: ESIPT-based ratiometric fluorescence probe for the intracellular imaging of peroxynitrite.

Chem Commun (Camb) 2019 03 12;55(25):3674. Epub 2019 Mar 12.

Department of Chemistry, University of Bath, Bath, BA2 7AY, UK. and Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan.

Correction for 'ESIPT-based ratiometric fluorescence probe for the intracellular imaging of peroxynitrite' by Luling Wu et al., Chem. Commun., 2018, 54, 9953-9956.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9cc90119aDOI Listing
March 2019

A Selective Deprotection Strategy for the Construction of trans-2-Aminocyclopropanecarboxylic Acid Derived Peptides.

Org Lett 2019 01 17;21(1):100-103. Epub 2018 Dec 17.

ICMMO, CNRS , Université Paris-Sud, Université Paris-Saclay , 15 rue Georges Clemenceau , 91405 Orsay Cedex , France.

A procedure allowing access to unprecedented tripeptides containing a trans-2-aminocyclopropanecarboxylic acid residue in their central position has been established. The key features of the strategy are the use of a masked trans-2-aminocyclopropanecarboxylic acid monomer equivalent for C-terminal coupling and full N-Boc protection of all amide groups until the final step.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.orglett.8b03533DOI Listing
January 2019

Excited-state intramolecular proton-transfer (ESIPT) based fluorescence sensors and imaging agents.

Chem Soc Rev 2018 Nov;47(23):8842-8880

Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c8cs00185eDOI Listing
November 2018

An ESIPT Probe for the Ratiometric Imaging of Peroxynitrite Facilitated by Binding to Aβ-Aggregates.

J Am Chem Soc 2018 10 16;140(43):14267-14271. Epub 2018 Oct 16.

Department of Chemistry , University of Bath , Bath BA2 7AY , U.K.

A series of 3-hydroxyflavone (3-HF) ESIPT (excited-state intramolecular proton transfer) boronate-based fluorescent probes have been developed for the detection of peroxynitrite (ONOO). The dyes are environmentally sensitive, and each probe exhibited a ratiometric response toward ONOO in a micellar environment. The probes were used to image different aggregation states of amyloid-β (Aβ) in the presence of ONOO. The 3-HF-OMe probe was found to produce a ratiometric response toward ONOO when bound to Aβ aggregates, resulting in a novel host-guest ensemble, which adds insight into the development of other ESIPT-based probes for the simultaneous sensing of fibrous proteins/peptides and environmental ROS/RNS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jacs.8b08457DOI Listing
October 2018

ESIPT-based fluorescence probe for the rapid detection of peroxynitrite 'AND' biological thiols.

Chem Commun (Camb) 2018 Oct;54(80):11336-11339

Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.

An ESIPT-based 'AND' logic fluorescence probe (GSH-ABAH) was developed for the simultaneous detection of ONOO- and biological thiols. GSH-ABAH was shown to have good cell permeability and with the addition of just SIN-1 (ONOO- donor) or GSH, no fluorescence response was observed in live cells. However, in the presence of both analytes GSH-ABAH could be used to image exogenous ONOO- 'AND' GSH added to RAW264.7 cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c8cc06917dDOI Listing
October 2018

Correction: A bodipy based hydroxylamine sensor.

Chem Commun (Camb) 2018 09;54(77):10922

Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.

Correction for 'A bodipy based hydroxylamine sensor' by Adam C. Sedgwick et al., Chem. Commun., 2017, 53, 10441-10443.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c8cc90409jDOI Listing
September 2018

Correction: Boronate based fluorescence (ESIPT) probe for peroxynitrite.

Chem Commun (Camb) 2018 09;54(76):10775

Department of Chemistry, University of Bath, BA2 7AY, UK.

Correction for 'Boronate based fluorescence (ESIPT) probe for peroxynitrite' by Adam C. Sedgwick et al., Chem. Commun., 2016, 52, 12350-12352.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c8cc90408aDOI Listing
September 2018

ESIPT-based ratiometric fluorescence probe for the intracellular imaging of peroxynitrite.

Chem Commun (Camb) 2018 Sep 17;54(71):9953-9956. Epub 2018 Aug 17.

Department of Chemistry, University of Bath, Bath, BA2 7AY, UK. and Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan.

In this work, we set out to develop an endoplasmic reticulum (ER) directed ESIPT-based ONOO ratiometric fluorescent probe (ABAH-LW). ABAH-LW was synthesized in four steps and found to have a high sensitivity and selectivity towards the detection of ONOO. ABAH-LW was able to detect low concentrations of ONOO (limit of detection = 21.4 nM) within seconds producing a ratiometric change in fluorescence intensity. ABAH-LW further demonstrated the ability to ratiometrically image endogenous and exogenous ONOO in HeLa cells. Moreover, co-localization experiments were carried out using commercially available ER-Tracker Red, Lyso-Tracker Red and Mito-Tracker-Red, which were co-stained with ABAH-LW in HeLa cells. For ER-Tracker Red, Pearson's correlation co-efficient of 0.93 was determined and 3D surface plot analysis illustrated a large overlap between ABAH-LW and ER-Tracker Red using both red and blue channels. In addition some co-localisation with Mito-Tracker Red and ABAH-LW was observed (0.73).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c8cc04919jDOI Listing
September 2018

Fluorescence-Based Tool To Detect Endogenous Peroxynitrite in M1-Polarized Murine J774.2 Macrophages.

Anal Chem 2018 09 23;90(17):10621-10627. Epub 2018 Aug 23.

Department of Chemistry , University of Bath , Bath BA2 7AY , United Kingdom.

Oxidative stress and inflammation are intrinsically linked to each other. In addition, they are implicated in the evolution and progression of noncommunicable diseases (NCDs). Large amounts of reactive oxygen species (ROS) are generated as part of the immune response toward NCDs. Among all of the ROS species, peroxynitrite (ONOO) has the shortest half-life with <20 ms under typical physiological conditions. Hence, detecting ONOO and studying its generation in vitro allows for a better understanding of inflammatory processes. We demonstrate that peroxyresorufin-1 (PR1) is a selective and sensitive ONOO fluorescence-based sensor in J774.2 macrophages. PR1 was able to detect changes in ONOO production upon investigation of different factors: enhanced generation of ONOO through LPS and IFN-γ as well as diminished ONOO production with the introduction of superoxide scavengers and nitric oxide synthase inhibitors. Our study validates PR1 as an effective tool for the detection of ONOO in J774.2 murine macrophages and should allow for further elucidation of ROS biology and chemistry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.analchem.8b03035DOI Listing
September 2018

ESIPT-based fluorescence probe for the rapid detection of hypochlorite (HOCl/ClO).

Chem Commun (Camb) 2018 Jul;54(61):8522-8525

Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.

ESIPT-based fluorescence probes are emerging as an attractive tool for the detection of biologically relevant analytes owing to their unique photophysical properties. In this work, we have developed an ESIPT-based fluorescence probe (TCBT-OMe) for the detection of HClO/ClO- through the attachment of a bioorthogonal dimethylthiocarbamate linker. TCBT-OMe was shown to rapidly detect HClO/ClO- (<10 s) at biologically relevant concentrations (LoD = 0.16 nM) and have an excellent selectivity towards others ROS/RNS and amino acids. Therefore, TCBT-OMe was tested in live cells and was successfully shown to be able to detect endogenous and exogenous HClO/ClO- in HeLa cells. Additionally, TCBT-OMe acts as a dual input logic gate for Hg2+ and H2O2. Interestingly, Hg2+ alone gradually causes a fluorescence response but requires >30 min to produce a fluorescence response. Test strips containing TCBT-OMe were prepared and were demonstrated as an effective way to detect HClO/ClO- in water. Furthermore, TCBT-OMe was shown to detect exogenously added HClO/ClO- in three different water samples with little interference thus demonstrating the effectiveness as a method for the detection of HClO/ClO- in drinking water samples.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c8cc03717eDOI Listing
July 2018

'AND'-based fluorescence scaffold for the detection of ROS/RNS and a second analyte.

Chem Commun (Camb) 2018 Jul;54(61):8466-8469

Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.

Traditionally, fluorescence probes have focused on the detection of a single biomarker for a specific process. In this work, we set out to develop a number of fluorescence probes that enable the detection of a chosen analyte in the presence of reactive oxygen/nitrogen species (ROS/RNS). These fluorescence probes when activated result in the formation of the highly fluorescent pink dye, resorufin. Therefore, we have labelled these fluorescent probes as 'Pinkments'. Our first 'Pinkment' was shown to detect biologically relevant concentrations of ONOO- and have an excellent selectivity against other ROS/RNS. Pinkment-OH was developed to provide a core unit which could be easily functionalised to produce a range of 'AND' based fluorescence probes for the detection of ROS/RNS and a second analyte. For proof of concept, we synthesised Pinkment-OTBS and Pinkment-OAc. These 'AND'-based probes were successfully shown to detect ROS/RNS and F- or esterase, respectively.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c8cc04316gDOI Listing
July 2018

The development of a novel AND logic based fluorescence probe for the detection of peroxynitrite and GSH.

Chem Sci 2018 Apr 16;9(15):3672-3676. Epub 2018 Mar 16.

Department of Chemistry , University of Bath , Bath , BA2 7AY , UK . Email: ; Email: ; Email:

We have developed a novel AND logic based fluorescence probe for the simultaneous detection of ONOO and GSH (). The probe was synthesised over three steps starting from commercially available fluorescein. The probe was constructed by attaching the GSH reactive motif, 2,4-dinitrobenzenesulfonyl, to the previously reported boronate fluorescence based probe, . produced only a small fluorescence response towards the addition of GSH or ONOO separately. However, when the probe was exposed to both analytes, there was a significant (40-fold) fluorescence enhancement. demonstrated an excellent selectivity towards both GSH and ONOO. In cellular imaging experiments the probe was shown to be cell permeable with no 'turn-on' response observed for the addition of either GSH or ONOO separately. However, in the presence of both analytes, a clear fluorescence response was observed in live cells. was further able to monitor the co-existence of metabolically produced ONOO and GSH by exogenous stimulation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c8sc00733kDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5935063PMC
April 2018

Long-wavelength TCF-based fluorescence probes for the detection and intracellular imaging of biological thiols.

Chem Commun (Camb) 2018 May;54(38):4786-4789

Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.

Two 'turn on' TCF-based fluorescence probes were developed for the detection of biological thiols (TCF-GSH and TCFCl-GSH). TCF-GSH was shown to have a high sensitivity towards glutathione (GSH) with a 0.28 μM limit of detection. Unfortunately, at higher GSH concentrations the fluorescence intensity of TCF-GSH decreased and toxicity was observed for TCF-GSH in live cells. However, TCFCl-GSH was shown to be able to detect GSH at biologically relevant concentrations with a 0.45 μM limit of detection. No toxicity was found for TCFCl-GSH and a clear 'turn on' with good photostability was observed for the exogenous addition of GSH, Cys and HCys. Furthermore, TCFCl-GSH was used to evaluate the effects of drug treatment on the levels of GSH in live cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c8cc01661eDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5944426PMC
May 2018