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International audience; Surface-confined host–guest chemistry at the air/solid interface is used for trapping a functionalized 3D Zn–phthalocyanine complex into a 2D porous supramolecular template allowing the large area functionalization of an sp2-hybridized carbon-based substrate as evidenced by STM, resonance Raman spectroscopy, and water contact angle measurements.

Summary Nanodiamonds (NDs) are emerging delivery systems with biomedical applications and interesting perspectives in oncology. Their use has been proposed to assist the internalization of anticancer drugs and to decrease administered drug doses. The pro-apoptotic peptide ERα17p, which is issued from the hinge/N-terminus parts of the AF2 region of the human estrogen receptor α (ERα), is active at a concentration of 10 μM on breast cancer cells and particularly on those cancer cells that are ERα-positive. We have synthesized ND@ERα17p conjugates by physisorption of the cationic peptide ERα17p on the surface of anionic NDs. Resulting ND@ERα17p suspensions were characterized by far-UV electronic circular dichroism (ECD), dynamic light scattering (DLS) and zetametry. We then tested the anti-proliferative action of ND@ERα17p on ERα-positive MCF-7 breast carcinoma cells. ND@ERα17p allowed a decrease of the active concentration to 0.1 nM (ND@ERα17p), revealing unambiguously that NDs could be used to improve the anti-proliferative action of this peptide. This preliminary study proposes a novel approach for enhancing the apoptotic action displayed by ERα17p, in the context of breast cancer.

The internalization of cell-penetrating peptides (CPPs) into liposomes (large unilamellar vesicles, LUVs) was studied with a rapid and robust procedure based on the quenching of a small fluorescent probe, 7-nitrobenz-2-oxa-1,3-diazole (NBD). Quenching can be achieved by reduction with dithionite or by pH jump. LUVs with different compositions of phospholipids (PLs) were used to screen the efficacy of different CPPs. In order to "validate" the composition of the membrane models, a control cationic peptide, which does not enter eukaryotic cells, was included in the study. It was found that pure DOPG or DOPG within ternary mixtures with cholesterol are the most appropriate models for studying CPP translocation. An anionic lipid, such as DOPG, is required for the adsorption of the basic peptides on the surface of LUVs. In addition, it acts as transfer agent through the lipid bilayer. A fluid phase and/or the presence of phase defects also appear mandatory for the internalization to occur. The neutralization of charges within an inverted micelle demonstrated in the case of DOPG and also proposed for a ternary mixture of PLs might not be the only mechanism for the CPP translocation. Finally, it is shown that oleic acid facilitates the entry inside LUVs in gel phase of a series of cationic peptides including CPPs and also the negative control peptide PKCi.

Antibody detection in autoimmune disorders, such as multiple sclerosis (MS) and Rett syndrome (RTT) can be achieved more efficiently using synthetic peptides. The previously developed synthetic antigenic probe CSF114(Glc), a type I' beta-turn N-glucosylated peptide structure, is able to recognize antibodies in MS and RTT patients' sera as a sign of immune system derangement. We report herein the design, synthesis, conformational analysis, and immunological evaluation of a collection of glycopeptide analogs of CSF114(Glc) to characterize the specific role of secondary structures in MS and RTT anti-body recognition. Therefore, we synthesized a series of linear and cyclic short glucosylated sequences, mimicking different b-turn conformations, which were evaluated in inhibition enzyme-linked immunosorbent assays (ELISA). Calculated IC50 ranking analysis allowed the selection of the candidate octapeptide containing two (S) 22-amino-4-pentynoic acid (L-Pra) residues Ac-PraRRN(Glc) GHT-Pra-NH2, with an IC50 in the nanomolar range. This peptide was adequately modified for solidphase ELISA (SP-ELISA) and surface plasmon resonance (SPR) experiments. Pra-RRN(Glc) GHT-Pra-NH2 peptide was modified with an alkyl chain linked to the N-terminus, favoring immobilization on solid phase in SP-ELISA and differentiating IgG antibody recognition between patients and healthy blood donors with a high specificity. However, this peptide displayed a loss in IgM specificity and sensitivity. Moreover, an analog was obtained after modification of the octapeptide candidate Ac-Pra-RRN(Glc) GHT-Pra-NH2 to favor immobilization on SPR sensor chips. SPR technology allowed us to determine its affinity (K-D=16.4 nM), 2.3 times lower than the affinity of the original glucopeptide CSF114(Glc) (K-D=7.1 nM).

International audience; The recurring issue with cell penetrating peptides is how to increase direct translocation vs. endocytosis, to avoid premature degradation. Acylation by a cis unsaturated chain (C22:6) of a short cationic peptide provides a new rational design to favour diffuse cytosolic and dense Golgi localisations.

Several examples of sol–gel preparation of doped materials are taken to illustrate the various situations where the doping elements are responsible for the main function of the material or govern its structure. Other examples are used to illustrate that sometimes unexpected effects can be observed like structural modification and the appearance of new properties. Rare earth doped scintillators demonstrate higher homogeneity for materials prepared via sol–gel chemistry when compared with classical solid state reaction. The XRD study of rare earth doped orthoborates shows that doping can affect the vaterite to calcite phase transition observed in these compounds. A Raman spectroscopic study has been performed on doped silica xerogels and it has been shown that doping ions can modify greatly the densification process in these amorphous materials. Finally, it has been evidenced that sol–gel chemistry allows the preparation of bioactive ceramics with enhanced properties. In particular Zn-doped HAP with anti inflammatory properties has been prepared and Sr-doped bioactive glasses have demonstrated superior in-vitro bioactivity as evidenced by PIXE-RBS study.

Confocal laser scanning microscopy (CLSM) is the most popular technique for mapping the subcellular distribution of a fluorescent molecule and is widely used to investigate the penetration properties of exogenous macromolecules, such as cell-penetrating peptides (CPPs), within cells. Despite the membrane-association propensity of all these CPPs, the signal of the fluorescently labeled CPPs did not colocalize with the plasma membrane. We studied the origin of this fluorescence extinction and the overall consequence on the interpretation of intracellular localizations from CLSM pictures. We demonstrated that this discrepancy originated from fluorescence self-quenching. The fluorescence was unveiled by a “dilution” protocol, i.e. by varying the ratio fluorescent/non-fluorescent CPP. This strategy allowed us to rank with confidence the subcellular distribution of several CPPs, contributing to the elucidation of the penetration mechanism. More generally, this study proposes a broadly applicable and reliable method to study the subcellular distribution of any fluorescently labeled molecules.

Three-electrode micro-cells equipped with a conventional reference electrode (SCE) were easily constructed based on micro-volume droplets suspended by capillary forces to the fritted glass of the SCE bridge. Working and counter electrodes were simply inserted through the droplet surface, allowing classical electrochemistry to be readily performed in minute samples. Keywords: Electroanalysis, Micro-volume, Droplet, Platinization, Cell-penetrating peptide

Antibody detection in autoimmune disorders, such as multiple sclerosis (MS) and Rett syndrome (RTT) can be achieved more efficiently using synthetic peptides. The previously developed synthetic antigenic probe CSF114(Glc), a type I' β-turn N-glucosylated peptide structure, is able to recognize antibodies in MS and RTT patients' sera as a sign of immune system derangement. We report herein the design, synthesis, conformational analysis, and immunological evaluation of a collection of glycopeptide analogs of CSF114(Glc) to characterize the specific role of secondary structures in MS and RTT antibody recognition. Therefore, we synthesized a series of linear and cyclic short glucosylated sequences, mimicking different β-turn conformations, which were evaluated in inhibition enzyme-linked immunosorbent assays (ELISA). Calculated IC50 ranking analysis allowed the selection of the candidate octapeptide containing two (S)-2-amino-4-pentynoic acid (L-Pra) residues Ac-Pra-RRN(Glc)GHT-Pra-NH2 , with an IC50 in the nanomolar range. This peptide was adequately modified for solid-phase ELISA (SP-ELISA) and surface plasmon resonance (SPR) experiments. Pra-RRN(Glc)GHT-Pra-NH2 peptide was modified with an alkyl chain linked to the N-terminus, favoring immobilization on solid phase in SP-ELISA and differentiating IgG antibody recognition between patients and healthy blood donors with a high specificity. However, this peptide displayed a loss in IgM specificity and sensitivity. Moreover, an analog was obtained after modification of the octapeptide candidate Ac-Pra-RRN(Glc)GHT-Pra-NH2 to favor immobilization on SPR sensor chips. SPR technology allowed us to determine its affinity (KD = 16.4 nM), 2.3 times lower than the affinity of the original glucopeptide CSF114(Glc) (KD = 7.1 nM).

Microstructure, luminescence and scintillation of LuBO3 sprayed coatings on transparent substrates were analyzed. Parameters leading to the achievement of homogeneous films with the expected composition were investigated. Several thickness screens composed of pure and Eu3+ or Ce3+ doped LuBO3 phases were prepared. Finally scintillation performances were measured in comparison with the standard Gd2O2S:Tb scintillating screen.

LnPO 4 (Ln=Y, Lu) orthophosphates have been prepared by a new sol–gel route. Eu 3+ doped materials have also been synthesized and studied. X-ray diffraction performed on all samples showed that pure xenotime phase is obtained in all cases even for doped samples. The morphology of the powders has been determined and small grains with narrow size distribution are evidenced. Finally the optical properties of the doped materials have been studied, the substitution of Eu 3+ for Ln 3+ is confirmed and the radiative lifetimes are compatible with potential applications of these phosphors.

International audience; : In this study, the direct translocation of cell-penetrating peptides (CPPs) into large unilamellar vesicles (LUVs) was shown to be rapid for all the most commonly used CPPs. This translocation led within a few minutes to intravesicular accumulation up to 0.5 mM, with no need for a transbilayer potential. The accumulation of CPPs inside LUVs was found to depend on CPP sequence, CPP extravesicular concentration and phospholipid (PL) composition, either in binary or ternary mixtures of PLs. More interestingly, the role of anionic phospholipid flip-flopping in the translocation process was ascertained. CPPs enhanced the flipping of PLs, and the intravesicular CPP accumulation directly correlated with the amount of anionic PLs that had been transferred from the external to the internal leaflet of the LUV bilayer, thus demonstrating the transport of peptide/lipid complexes as inverted micelles.

International audience; In this paper, we report the synthesis, the characterization and the scintillation properties of sol-gel derived Lu2SiO5 (LSO) powders. Ce3+, Eu3+ and Tb3+ doped LSO powders have been synthesized by an original sol-gel process. The purity of the materials has been checked by X-Ray diffraction, confirming the elaboration of monophasic powders even for doped samples. Finally, the scintillation properties of the rare earth doped materials have been studied, the substitution of Ln3+ (Ln: Ce, Eu or Tb) for Lu3+ is confirmed, the scintillation yields have been calculated and the afterglow have also been measured, confirming the potentiality of the sol-gel derived LSO.

International audience; The functionalization of nanoparticle surfaces remains a major challenge for broader applications in biology. To study the physisorption of peptides on nanodiamonds (NDs), we developed reliable and facile methods: UV titration, MALDI-TOF mass spectrometry or fluorescence spectrophotometry. These readily applicable procedures allowed us to analyze the adsorption and desorption behaviors of different cationic peptides. A rough estimate led to propose that an average of three to four shells of amphiphilic peptides rapidly adsorbed on NDs surface: about half of the molecules being adsorbed with a high affinity, while the other half may be exchanged within a few minutes. If a photoactivatable amino acid was incorporated in the peptide sequence, the subsequent irradiation allowed similarly the coating of three to five shells of peptides on the NDs surface, but in that case peptides were not exchangeable at all, even after a few days. Stable cationic nanodiamonds may be obtained by simple physisorption of amphiphilic peptides, leading to nanoparticles with a positive zeta potential in the appropriate range for biological applications.

For the first time, a sol−gel route is proposed for the well-known scintillator Lu2SiO5. The sol−gel process allows the production of both powders with nanosized grains and optical quality thin films. The optical properties of Ce3+-doped materials are similar to those reported previously for LSO single crystal. This new preparation strategy is very versatile and could provide a low-cost solution for the production of high-quality X-ray intensifying screens.

A cationic cell-penetrating peptide (CPP) labeled with both a ferrocenyl (Fc) moiety and a biotin (B) was successfully synthesized and investigated by electrochemistry. This original CPP derivative noted as Fc-CPP-B could be electrochemically detected, at a micromolar concentration, at a naked gold bead electrode. The presence of a biotin tag in the Fc-CPP-B complex allowed its complexation with avidin, which was itself tethered to a thiolated self-assembled monolayer. Such an avidin-modified gold surface, characterized by atomic force microscopy (AFM), allowed the immobilization of Fc-CPP-B onto the electrode surface, which greatly enhanced its electrochemical detection. Nevertheless, under these conditions the electrogenerated ferrocenium cation could not be reduced during the backward scan, indicating its unexpected reactivity when tethered within the avidin environment. In terms of detection and redox probe regeneration the best results were obtained at a glassy carbon electrode modified with a cation-exchange polymer. Ion-exchange voltammetry, performed under these conditions, allowed the pre-concentration of the peptide at the electrode surface thanks to the net positive charge of the CPP derivative. Interestingly, the anionic character of the polymer contributed to retain the electrogenerated cation Fc + in the film so that it could be reduced back to its original neutral form during the reverse voltammetric scans.

International audience; The ability of diamond nanoparticles (nanodiamonds, NDs) to deliver small interfering RNA (siRNA) into Ewing sarcoma cells is investigated with a view to the possibility of in-vivo anticancer nucleic-acid drug delivery. siRNA is adsorbed onto NDs that are coated with cationic polymer. Cell uptake of NDs is demonstrated by taking advantage of the NDs' intrinsic fluorescence from embedded color-center defects. Cell toxicity of these coated NDs is shown to be low. Consistent with the internalization efficacy, a specific inhibition of EWS/Fli-1 gene expression is shown at the mRNA and protein level by the ND-vectorized siRNA in a serum-containing medium.

Several examples of sol–gel preparation of doped materials are taken to illustrate the various situations where the doping elements are responsible for the main function of the material or govern its structure. Other examples are used to illustrate that sometimes unexpected effects can be observed like structural modification and the appearance of new properties. Rare earth doped scintillators demonstrate higher homogeneity for materials prepared via sol–gel chemistry when compared with classical solid state reaction. The XRD study of rare earth doped orthoborates shows that doping can affect the vaterite to calcite phase transition observed in these compounds. A Raman spectroscopic study has been performed on doped silica xerogels and it has been shown that doping ions can modify greatly the densification process in these amorphous materials. Finally, it has been evidenced that sol–gel chemistry allows the preparation of bioactive ceramics with enhanced properties. In particular Zn-doped HAP with anti inflammatory properties has been prepared and Sr-doped bioactive glasses have demonstrated superior in-vitro bioactivity as evidenced by PIXE-RBS study.

International audience; Nanodiamonds that were prepared by high pressure/high temperature were functionalized with biomolecules for biological applications. Nanodiamonds (NDs, < or =35 nm) that were coated by silanization or with polyelectrolyte layers were grafted with a fluorescent thiolated peptide via a maleimido function; this led to an aqueous colloidal suspension that was stable for months. These substituted NDs were not cytotoxic for CHO cells. Their capacity to enter mammalian cells, and their localisation inside were ascertained after labelling the nucleus and actin, by examining the cells by confocal, reflected light and fluorescence microscopy.

International audience; Rare earth doped Lu2SiO5 thin films have been prepared by combining sol-gel process and spin coating. Annealing treatment results in the crystallization of the film and efficient incorporation of rare earth doping ions. XPS and RBS spectrocopies showed that the composition of the films is close to the nominal one. Adventitious carbon has been observed and attributed to incomplete pyrolysis of metal-organic precursors. XPS concentrations profiles show a good homogeneity for the films. RBS demonstrated some inter-diffusion between amorphous carbon substrate and silicate films resulting in a gradient of carbon at the interface between the substrate and the film itself.

International audience; Lu1-xEuxBO3 and Lu1-xTbxBO3 powders have been prepared by a sol-gel process with 0 < x < 0.15 for Eu3+ and 0 < x < 0.05 for Tb3+. The purity of powders has been verified by X-Ray diffraction and the results confirm that all the materials have the vaterite type even if the calcination has been performed at 800°C. Furthermore, the solid solution for LuBO3 vaterite is observed up to x=0.15 and x=0.05 for europium and terbium ions respectively. So doping with Eu3+ or Tb3+ ions does not affect the structure. These materials have also been analyzed by Fourier Transform Infra Red Spectroscopy. The morphology of the powders has been studied by Scanning Electron Microscopy and shows a very nice morphology with small spherical particles with narrow size distribution. Optical properties have then been studied to confirm the effective substitution of Eu3+ or Tb3+ for Lu3+ ions and to determine the materials scintillation performances. The optima, in term of scintillation yield, are obtained for Eu3+ and Tb3+ concentration of x=0.05 in both cases. The afterglows have also been measured and confirm the potentiality of these materials as scintillators.

In this paper, the synthesis, the characterization and the scintillation properties of LuPO4 doped, with several concentrations of Ce3+, Eu3+ and Tb3+ ions, are presented. These materials have been synthesized by sol-gel process. The purity of powders has been verified by X-Ray diffraction and the results confirm the xenotime structure of all the materials. A thermogravimetric analysis allows the obtention of informations on the crystallisation of LuPO4 and the study of its evolution from the amorphous to crystalline form. The morphology of the powders has been studied by Scanning Electron Microscopy and shows that the powders are constituted of small particles with narrow size distribution. Optical properties have been studied in order to determine the scintillation performances of these materials. The optima are obtained for Ce3+, Eu3+ and Tb3+ concentration of respectively 0.1%, 10% and 5% with high scintillation yields. This study thus confirms the potentialities of these materials as scintillators.

Rare earth doped LuBO 3 thin films have been prepared by combining sol-gel process and coating techniques such as spin coating and spray pyrolysis. Annealing treatment results in the crystallization of the film as vaterite phase and incorporation of the doping ions in solid solution. XPS and RBS spectroscopies showed that the composition of the films is close to the nominal one. Adventitious carbon has been observed and attributed to incomplete pyrolysis of metal-organic precursors. XPS concentration profiles show a good homogeneity for the films. RBS demonstrated some inter-diffusion between amorphous carbon substrate and borate films resulting in a gradient of carbon at the interface between the substrate and the film itself. Finally scintillation spectra have been recorded and demonstrate the potentiality of these films to be used as X-ray intensifying screens.

For the first time, a sol−gel route is proposed for the well-known scintillator Lu2SiO5. The sol−gel process allows the production of both powders with nanosized grains and optical quality thin films. The optical properties of Ce3+-doped materials are similar to those reported previously for LSO single crystal. This new preparation strategy is very versatile and could provide a low-cost solution for the production of high-quality X-ray intensifying screens.

In this paper we report on preliminary results obtained on sol–gel derived inorganic scintillators. A new general scheme based on the use of alkoxide chemistry is proposed for the preparation of various scintillating materials including LuBO3, GdBO3, LuPO4 and Lu2SiO5. The materials are obtained as monophasic powders and as homogeneous transparent thin films for borates and silicate. Thermal behaviour is analysed and a study of the oxidation state of cerium ions is proposed by combining X-ray photoelectron spectroscopy and X-ray absorption near edge structure spectroscopy. A mixture of Ce3+ and Ce4+ is observed in proportions depending on the material. This presence of Ce4+ ions does not seem to greatly affect the observed scintillation yields of the materials. Efficient sol–gel derived scintillators have been prepared both as powders and thin films. The preparation of optical quality scintillator thin films could be the starting point for a new generation of scintillating materials. Finally, the versatility of the proposed synthesis route will allow extension of this study towards various other materials.

Ce3 +-doped LuBO3 powders have been prepared by a sol–gel process with Ce3 + concentration varying between 0 and 5 mol%. These materials have been analyzed by X-ray Diffraction and Fourier Transform Infra Red Spectroscopy. The results confirm that all the materials have the vaterite type even if the calcination has been performed at 800°C. Furthermore, doping with Ce3 + ions does not affect the structure and the vaterite is preserved even at 5% doping. Scanning Electron Microscopy showed a very uniform morphology with small spherical grains with a narrow size distribution. Optical properties have been studied to confirm the effective substitution of Ce3 + for Lu3 + ions and to determine the materials scintillation performances. It has been shown that 0.5% is the optimum Ce(III) concentration in term of scintillation yield with an X-ray conversion yield equivalent to that of standard BGO (Bi4Ge3O12). The afterglow has also been measured and confirms the potential of these materials as scintillators.