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Introduction
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Publications
Publications (159)
Characterization of nanoscale formulations is a continuous challenge. Size, morphology and surface properties are the most common characterizations. However, physicochemical properties inside the nanoparticles, like viscosity, cannot be directly measured....
Photoactivatable fluorescent probes are valuable tools in bioimaging for tracking cells down to single molecules and for single molecule localization microscopy. For the latter application, green emitting dyes are in demand. We herein developed an efficient green‐emitting photoactivatable furanyl‐BODIPY (PFB) and we established a new mechanism of p...
Hypothesis
Characterization of nanoscale formulations is a continuous challenge. Size, morphology and surface properties are the most common characterizations. However, physicochemical properties inside the nanoparticles, like viscosity, cannot be directly measured. Herein, we propose an original approach to measuring dynamic viscosity using a lipi...
The realm of self-healing materials integrates chemical and physical mechanisms that prevent wear and fracturing and extend the operational lifetime. Unlike the favorable rheology of amorphous soft materials that facilitates efficient contact between fragments, the efficiency of recovery of atomistically ordered materials is restricted by slower in...
DNA origami nanostructures (DOs) are promising tools for applications including drug delivery, biosensing, detecting biomolecules, and probing chromatin substructures. Targeting these nanodevices to mammalian cell nuclei could provide impactful approaches for probing, visualizing, and controlling biomolecular processes within live cells. We present...
Photoactivatable fluorescent probes are valuable tools in bioimaging for tracking cells down to single molecules and for single molecule localization microscopy. For the latter application, green emitting dyes are in demand. We herein developed an efficient green-emitting photoactivatable furanyl-BODIPY (PFB) and we established a new mechanism of p...
Efficient exciton transport is the essential property of natural and synthetic light-harvesting (LH) devices. Here we investigate exciton transport properties in LH organic polymer nanoparticles (ONPs) of 40 nm diameter....
DNA origami (DO) are promising tools for in vitro or in vivo applications including drug delivery; biosensing, detecting biomolecules; and probing chromatin sub-structures. Targeting these nanodevices to mammalian cell nuclei could provide impactful approaches for probing visualizing and controlling important biological processes in live cells. Her...
Although the human immunodeficiency virus type 1 lipid envelope has been reported to be enriched with host cell sphingomyelin and cholesterol, the molecular mechanism of the enrichment is not well understood. Viral Gag protein plays a central role in virus budding. Here, we report the interaction between Gag and host cell lipids using different qua...
Light‐harvesting is a fundamental process in nature, which inspires researchers to develop artificial systems for photocatalysis, photovoltaics, and biosensing. A previously introduced light‐harvesting nanoantenna, based on polymeric nanoparticles (NPs) loaded with rhodamine dyes and bulky hydrophobic counterions, provides a record‐breaking antenna...
The human immunodeficiency virus-1 (HIV-1) nucleocapsid protein (NCp7) is a nucleic acid chaperone protein with two highly conserved zinc fingers. To exert its key roles in the viral cycle, NCp7 interacts with several host proteins. Among them, the human NoL12 protein (hNoL12) was previously identified in genome wide screens as a potential partner...
Photomodulable fluorescent probes are drawing an increasing attention due to their applications in advanced bioimaging. Whereas photoconvertible probes can be advantageously used in tracking, photoswitchable probes constitute key tools for single molecule localization microscopy to perform super resolution imaging. Herein we shed light on a red and...
Förster resonance energy transfer (FRET) is essential in optical materials for light-harvesting, photovoltaics and biosensing, but its operating range is fundamentally limited by the Förster radius of ∼5 nm. Here, FRET between fluorescent organic nanoparticles (NPs) is studied for the first time in order to break this limit. The donor and acceptor...
Photodynamic therapy (PDT) is a photochemistry‐based medical treatment combining light at a specific wavelength and a photosensitizer (PS) in the presence of oxygen. Application of PDT as a conventional treatment is limited and clearly the approval in clinics of new PS is challenging. The selective accumulation of the PS in the targeted malignant c...
Invited for the cover of this issue is the group of Mayeul Collot at the University of Strasbourg (CNRS). The image depicts the effect of simple chemical tuning on coumarin dyes to tune and improve the DPIC photoconversion mechanism. Read the full text of the article at 10.1002/chem.202203933.
The tunability of the DPIC mechanism. A yellow‐emitting coumarin is connected to a “conversion meter” indicating the efficiency of conversion. The needle points at the different groups that have been attached to the pyrrole moiety. These groups are sorted from left to right according to the conversion yield, with a corresponding background ranging...
Dual‐emissive photoconvertible fluorophores (DPCFs) are powerful tools to unambiguously track labeled cells in bioimaging. We recently introduced a new rational mechanism called directed photooxidation‐induced conversion (DPIC) enabling efficient DPCFs to be obtained by conjugating a coumarin to aromatic singlet‐oxygen reactive moieties (ASORMs). P...
We herein present a new concept to produce dual‐color photoconvertible probes based on a mechanism called Directed Photooxidation Induced Conversion (DPIC). As a support of this mechanism, styryl‐coumarins (SCs) bearing Aromatic Singlet Oxygen Reactive Moieties (ASORMs) like furan and pyrrole have been synthesized. SCs are bright fluorophores, whic...
We herein present a new concept to produce dual‐color photoconvertible probes based on a mechanism called Directed Photooxidation Induced Conversion (DPIC). As a support of this mechanism, styryl‐coumarins (SCs) bearing Aromatic Singlet Oxygen Reactive Moieties (ASORM) like furan and pyrrole have been synthesized. SCs are bright fluorophores, which...
The Human Immunodeficiency Virus-1 (HIV-1) nucleocapsid protein (NC) as a mature protein or as a domain of the Gag precursor plays important roles in the early and late phases of the infection. To better understand its roles, we searched for new cellular partners and identified the RNA-binding protein Unr/CSDE1, Upstream of N-ras, whose interaction...
Time-resolved fluorescence anisotropy (TRFA) provides key information on the dynamics of biomolecules and their interaction with ligands. However, since natural nucleosides are almost non-fluorescent, its application to DNA duplexes (dsDNA) requires fluorescent labels, which can alter dsDNA stability, hinder protein binding, and complicate interpre...
Thienoguanosine (thG) is an isomorphic fluorescent guanosine (G) surrogate, which almost perfectly mimics the natural G in DNA duplexes and may therefore be used to sensitively investigate for example protein-induced local conformational changes. To fully exploit the information given by the probe, we carefully re-investigated the thG spectroscopic...
Exciton density dynamics recorded in time-resolved spectroscopic measurements is a useful tool to recover information on energy transfer (ET) processes that can occur at different timescales, up to the ultrafast regime. Macroscopic models of exciton density decays, involving both direct Förster-like ET and diffusion mechanisms for exciton-exciton a...
Inhaled transfection particles have to penetrate the mucus layer lining the airways to successfully deliver their therapeutic nucleic acid payload to target cells in the underlying epithelium. However, the in vitro models used for evaluating gene carrier efficiency often disregard this viscous defensive barrier. In this study, the two mucus-secreti...
Interconversions between nucleic acid structures play an important role in transcriptional and translational regulation and also in repair and recombination. These interconversions are frequently promoted by nucleic acid chaperone proteins. To monitor their kinetics, Förster resonance energy transfer (FRET) is widely exploited using ensemble fluore...
Histone H2AX phosphorylated at serine 139 (γ-H2AX) is a hallmark of DNA damage, signaling the presence of DNA double-strand breaks and global replication stress in mammalian cells. While γ-H2AX can be visualized with antibodies in fixed cells, its detection in living cells was so far not possible. Here, we used immune libraries and phage display to...
Fluorescent nucleoside analogues (FNAs) are structurally diverse mimics of the natural essentially non-fluorescent nucleosides which have found numerous applications in probing the structure and dynamics of nucleic acids as well as their interactions with various biomolecules. In order to minimize disturbance in the labelled nucleic acid sequences,...
Overexpression of EGFR drives glioblastomas (GBM) cell invasion but these tumours remain resistant to EGFR-targeted therapies such as tyrosine kinase inhibitors (TKIs). Endocytosis, an important modulator of EGFR function, is often dysregulated in glioma cells and is associated with therapy resistance. However, the impact of TKIs on EGFR endocytosi...
Very few proteins are reported to bind specific lipids. Because of the high selectivity and strong binding to specific lipids, lipid-targeting pore forming toxins (PFTs) have been employed to study the distribution of lipids in cell- and model-membranes. Non-toxic and monomeric PFT-derivatives are especially useful to study living cells. In this ch...
Background
A positive surface charge has been largely associated with nanoparticle (NP) toxicity. However, by screening a carbon NP library in macrophages, we found that a cationic charge does not systematically translate into toxicity. To get deeper insight into this, we carried out a comprehensive study on 5 cationic carbon NPs (NP2 to NP6) exhib...
In the quest for the identification of the light emitter(s) responsible for the firefly bioluminescence, the study of oxyluciferin analogues with controlled chemical and electronic structures is of particular importance. In this article, we report the results of our experimental and computational investigation of the pH-dependent absorption spectra...
Thienoguanosine (thG) is an isomorphic guanosine (G) surrogate that almost perfectly mimics G in nucleic acids. To exploit its full potential and lay the foundation for future applications, twenty DNA duplexes, where the bases facing and neighboring thG were systematically varied, were thoroughly studied using fluorescence spectroscopy, molecular d...
ABSTRACT The human immunodeficiency virus type 1 Gag precursor specifically selects the unspliced viral genomic RNA
(gRNA) from the bulk of cellular and spliced viral RNAs via its nucleocapsid (NC) domain and drives gRNA encapsidation at
the plasma membrane (PM). To further identify the determinants governing the intracellular trafficking of Gag-gR...
The HIV-1 Gag precursor specifically selects the unspliced viral genomic RNA (gRNA) from the bulk of cellular and spliced viral RNAs via its nucleocapsid (NC) domain and drives gRNA encapsidation at the plasma membrane (PM). To further identify the determinants governing the intracellular trafficking of Gag-gRNA complexes and their accumulation at...
One of the most characterized bioluminescent reactions involves the firefly luciferase that catalyzes the oxidation of the luciferin producing oxyluciferin in its first excited state. While relaxing to the ground state, oxyluciferin emits visible light with an emission maximum that can vary from green to red. Oxyluciferin exists under six different...
The thienoguanine nucleobase (thGb) is an isomorphic fluorescent analogue of guanine. In aqueous buffer at neutral pH, thGb exists as a mixture of two ground-state H1 and H3 keto–amino tautomers with distinct absorption and emission spectra and high quantum yield. In this work, we performed the first systematic photophysical characterization of thG...
The HIV-1 Gag precursor specifically selects the unspliced viral genomic RNA (gRNA) from the bulk of cellular and spliced viral RNAs via its nucleocapsid (NC) domain and drives gRNA encapsidation at the plasma membrane (PM). To further identify the determinants governing the intracellular trafficking of Gag-gRNA complexes and their accumulation at...
The photophysical properties of oxyluciferin, the light emitter responsible for firefly bioluminescence, are pH‐dependent. One of the potential proton acceptor/donor is adenosine monophosphate (AMP). We have studied three oxyluciferin synthetic analogues with or without AMP, in water, in the pH=5 to 11 range, using both experimental steady‐state ab...
Thienoguanosine (thG) is an isomorphic analogue of guanosine with promising potentialities as fluorescent DNA label. As a free probe in protic solvents, thG exists in two tautomeric forms, identified as the H1, being the only one observed in nonprotic solvents, and H3 keto–amino tautomers. We herein investigate the photophysics of thG in solvents o...
Phosphorylated histone H2AX (γ-H2AX), a central player in the DNA damage response (DDR), serves as a biomarker of DNA double-strand break repair. Although DNA damage is generally visualized by the formation of γ-H2AX foci in injured nuclei, it is unclear whether the widespread uniform nuclear γ-H2AX (called pan-nuclear) pattern occurring upon inten...
Cationic carbon dots (CDs) have been recently described as nucleic acid carriers with high in vitro and in vivo transfection efficiency and imaging properties. However, developing nanoparticles (NPs) for biomedical applications requires assessing their safety. In the present study, we characterized the cell uptake and trafficking, as well as the ce...
How small should nanoparticles be in order to travel freely through the cytosol similar to proteins? Answering this question remains a challenge, because the majority of nanoparticles are relatively large and their size cannot be finely tuned to match that of proteins. Here, poly(methyl methacrylate) copolymers with varied fraction and type of char...
Multi-colour super-resolution localization microscopy is an efficient technique to study a variety of intracellular processes, including protein-protein interactions. This technique requires specific labels that display transition between fluorescent and non-fluorescent states under given conditions. For the most commonly used label types, photoact...
Introduction
Overexpression of epidermal growth factor (EGFR) drives glioblastoma (GBM) cell invasion and tumour progression. EGFR has been a major therapeutic target in GBM. However, clinical trials were disappointing, and we are still missing molecular basis to explain these poor results. In other solid tumours, extracellular matrix proteins foun...
Ionic inorganic matrices such as calcite are known to occlude ions, organic molecules and proteins, and this process is at the core of biomineralization. In article number 1700176, by using labeled cowpea mosaic virus, Panče Naumov and co‐workers demonstrate that calcite can occlude biomolecules as large as viruses up to several percent by mass. Th...
The concept of biomineralization and encapsulation of organic molecules into inorganic matrices to alter and enhance their physical properties has been evolved and perfected in natural systems. Being inspired by the natural biomineralization of foreign components into calcite, here the inclusion of a plant virus, cowpea mosaic virus (CPMV) of 5.4%...
Firefly bioluminescence is a quite efficient process largely used for numerous applications. However, some fundamental photochemical properties of the light emitter are still to be analyzed. Indeed, the light emitter, oxyluciferin, can be in six different forms due to inter-exchange reactions. In this work, we present the simulation of the absorpti...
Owing to a technical error, the wrong version of the Supplementary Information was published for this Article; the equation E = xcoupled donors × ElocalFRET related to Supplementary Table 6 appeared incorrectly. This error has now been corrected.
Here, we explore the enhancement of single-molecule emission by a polymeric nanoantenna that can harvest energy from thousands of donor dyes to a single acceptor. In this nanoantenna, the cationic dyes are brought together, in very close proximity, using bulky counterions, thus enabling ultrafast diffusion of excitation energy (≤ 30 fs) with minima...
Expanded View Figures PDF
SAGA and ATAC are two distinct chromatin modifying co-activator complexes with distinct enzymatic activities involved in RNA polymerase II (Pol II) transcription regulation. To investigate the mobility of co-activator complexes and general transcription factors in live-cell nuclei, we performed imaging experiments based on photobleaching. SAGA and...
A π-extended boranil (PEB) dye has been synthesized and its photophysical properties have been recorded in a range of solvents. The dye exhibits an intense solvatochromic fluorescence emission covering the entire visible spectrum and the near infra-red (NIR) region (from λ=534 to 764 nm) with quantum yields up to 69 %. Embedment of the PEB dye in t...
The Front Cover picture shows a three-dimensional representation of a π-extended boranil dye and its metaphoric vectorization in water which enables the monitoring of cellular distribution using fluorescence microscopy. More information can be found in the Communication by J. Massue, G. Ulrich and co-workers (DOI: 10.1002/cptc.201700012).
The front cover artwork is provided by the Institut de Chimie et Procédés pour l'Energie, l'Environnement et la Santé (ICPEES) at the University of Strasbourg, France. The image shows a 3D representation of a π-extended Boranil dye and its metaphoric vectorization in water which enables the monitoring of cellular distribution using fluorescence mic...