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With the objective to formulate multifunctional nanosized liposomes to target amyloid deposits in Alzheimer Disease (AD) brains, a lipid–PEG–curcumin derivative was synthesized and characterized. Multifunctional liposomes incorporating the curcumin derivative and additionally decorated with a Blood Brain Barrier (BBB) transport mediator (anti-Transferin antibody) were prepared and characterized. The fluorescence intensity of curcumin derivative was found to increase notably when the curcumin moiety was in the form of a diisopropylethylamine (DIPEA) salt. Both curcumin-derivative liposomes and curcumin-derivative Anti-TrF liposomes showed a high affinity for the amyloid deposits, on post-mortem brains samples of AD patients. The ability of both liposomes to delay Aβ1-42 peptide aggregation was confirmed by Thioflavin assay. However, the decoration of the curcumin-derivative liposomes with the Anti-TrF improved significantly the intake by the BBB cellular model. Results verify that the attachment of an antibody on the curcumin-liposome surface does not block deposit staining or prevention of Aβ aggregation, while the presence of the curcumin–PEG–lipid conjugate does not reduce their brain-targeting capability substantially, proving the potential of such multifunctional NLs for application in Alzheimer disease treatment and diagnosis.

Coccidiosis is a common parasitic disease of broiler chickens caused by single-celled protozoan parasites of the genus Eimeria which are commonly referred to as coccidian. This is an infective disease of the digestive tract which is most frequent with poultry, causing a decrease in daily increment, prolonged fattening, poorer skin pigmentation, slower feed conversion and increased mortality. The disease is caused by Protozoas from the genera of Eimeria, Isospora and Cryptospora, and it is manifested by damaging the intestine epithelial cells, less frequently the bile duct and renal tubuli. Coccidiosis is traditionally controlled by chemotherapy. There are many anticoccidial preparations which are used in the prevention of coccidiosis. We are chose a polyether monocarboxylic acid - salinomycine. Salinomycin is monovalent carboxyl-polyether ionophores. Salinomycin, produced by Streptomyces albus, destroys the cell membranes and causes their lysis. Salinomycin and other ionophoric antibiotics combine with a number of mono and divalent cations and in the form of bi-complexes make it possible to transfer metal ions through lipid hydrophobic membrane, and when they are added to diet, they change bioavailability, gut uptake and absorption and reserves of nutrient tissues. In this paper has been developed and validated process of Liquid chromatography determination of ionophoric coccidiostat salinomycin with UV spectrophotometric detection and post-column derivatisation with dimethylaminobenzaldehyde (DMAB). The method is based on extraction of salinomycin in animal feed samples using mixture acetonitrile-water (80:20, v/v) and purification of extracts obtained by the filter 0,2 μm Acrodisc® PSF. The relative standard deviation (RSD) for reproducibility and accuracy varied from 2,4 to 8,8% and from 2,6% to 8,8%, respectively and the values for the relative recovery rate ranged from 89 to 98%. The limit of detection (LOD) and limit of quantification (LOQ) were estimated to be below 47 μg/kg and 71 μg/kg, respectively. Based on this results, it is concluded that the described method is accurate, precise, selective and reproducible and can be applied for determination of salinomycine in feeds and premixes for poultry.

Accumulation of amyloid peptide (Aβ) in senile plaques is a hallmark lesion of Alzheimer disease (AD). The design of molecules able to target the amyloid pathology in tissue is receiving increasing attention, both for diagnostic and for therapeutic purposes. Curcumin is a fluorescent molecule with high affinity for the Aβ peptide but its low solubility limits its clinical use. Curcumin-conjugated nanoliposomes, with curcumin exposed at the surface, were designed. They appeared to be monodisperse and stable. They were non-toxic in vitro, down-regulated the secretion of amyloid peptide and partially prevented Aβ-induced toxicity. They strongly labeled Aβ deposits in post-mortem brain tissue of AD patients and APPxPS1 mice. Injection in the hippocampus and in the neocortex of these mice showed that curcumin-conjugated nanoliposomes were able to specifically stain the Aβ deposits in vivo. Curcumin-conjugated nanoliposomes could find application in the diagnosis and targeted drug delivery in AD. From the Clinical Editor In this preclinical study, curcumin-conjugated nanoliposomes were investigated as possible diagnostics and targeted drug delivery system in Alzheimer’s disease, demonstrating strong labeling of Aβ deposits both in human tissue and in mice, and in vitro downregulation of amyloid peptide secretion and prevention of Aβ-induced toxicity.

Extensive knowledge of the protein components of the senile plaques, one of the hallmark lesions of Alzheimer's disease, has been acquired over the years, but their lipid composition remains poorly known. Evidence suggests that cholesterol contributes to the pathogenesis of Alzheimer's disease. However, its presence within senile plaques has never been ascertained with analytic methods. Senile plaques were microdissected from sections of the isocortex in three Braak VI Alzheimer's disease cases and compared with a similar number of samples from the adjoining neuropil, free of amyloid-beta peptide (A beta) deposit. Two cases were apo epsilon 4/apo epsilon 3, and one case was apo epsilon 3/apoepsilon3. A known quantity of (13)C-labeled cholesterol was added to the samples as a standard. After hexane extraction, cholesterol content was analyzed by liquid chromatography coupled with electrospray ionization mass spectrometry. The mean concentration of free cholesterol was 4.25 +/- 0.1 attomoles/microm(3) in the senile plaques and 2.2 +/- 0.49 attomoles/microm(3) in the neuropil (t = 4.41, P < 0.0009). The quantity of free cholesterol per senile plaque (67 +/- 16 femtomol) is similar to the published quantity of A beta peptide. The highly significant increase in the cholesterol concentration, associated with the increased risk of Alzheimer's disease linked to the apo epsilon 4 allele, suggests new pathogenetic mechanisms.

Solid-state complexes between para-sulphonatocalix[4]arene and a wide variety of organic cations, especially those containing amino groups are studied due to their potential applications. The structures of the complexes between para-sulphonatocalix[4]arene and norspermidine and triethyltetramine show the expected hydrogen bonding interactions between the ammonium and sulfonate groups.

The structure of calix[4]arene dihydrophosphonic acid in its complex with di-methyl ammonium and tetra-methyl ammonium cations shows a novel dimeric structural motifs for the calixarene assembly, with one calixarene unit showing distal aromatic rings inclined into the cavity and then both of the rings partially included into the cavity of a second molecule present in the flattened cone conformation.

A novel family of synthetic biodegradable poly(ester-amide)s (Arg-PEAs) was evaluated for their biosafety and capability to transfect rat vascular smooth muscle cells, a major cell type participating in vascular diseases. Arg-PEAs showed high binding capacity toward plasmid DNA, and the binding activity was inversely correlated to the number of methylene groups in the diol segment of Arg-PEAs. All Arg-PEAs transfected smooth muscle cells with an efficiency that was comparable to the commercial transfection reagent Superfect. However, unlike Superfect, Arg-PEAs, over a wide range of dosages, had minimal adverse effects on cell morphology, viability or apoptosis. Using rhodamine-labeled plasmid DNA, we demonstrated that Arg-PEAs were able to deliver DNA into nearly 100% of cells under optimal polymer-to-DNA weight ratios, and that such a high level of delivery was achieved through an active endocytosis mechanism. A large portion of DNA delivered, however, was trapped in acidic endocytotic compartments, and subsequently was not expressed. These results suggest that with further modification to enhance their endosome escape, Arg-PEAs can be attractive candidates for non-viral gene carriers owning to their high cellular uptake nature and reliable cellular biocompatibility.

We report adhesion, growth, and differentiation of mouse neural cells on ultra-thin films of an organic semiconductor, pentacene. We demonstrate that i) pentacene is structurally and morphologically stable upon prolonged contact with water, physiological buffer, and cell culture medium; ii) neural stem cells adhere to pentacene and remain viable on it for at least 15 days; iii) densely interconnected neural networks and glial cells develop on the pentacene surface after several days. This implies that adhesion proteins secreted by the cells find suitable adsorption loci to anchor the cells. Pentacene is also a suitable substrate for casting thin layers of cell adhesion molecules, such as laminin and poly-L-lysine. Our results show that pentacene, albeit being an aromatic molecule, allows neurons to adhere to and grow on it, which is possibly due to its tightly packed solid state structure. This structure remains unaltered upon exposure to water and interfacial force exerted by the cells. The integration of living cells into organic semiconductors is an important step towards the development of bio-organic electronic transducers of cellular signals from neural networks.

The crystal structures of the complexes between melamine mono-cations and para-calix[4]arene sulfonic acid and calix[4]arene dihydroxyphosphonic acid have been determined. In both cases the structure is based on a bilayer motif of calixarene molecules intercalated by motifs of melamine mono-cations. While in the complex with calix[4]arene dihydroxyphosphonic acid the motifs of melamine cations are parallel to the in-layer arrangement of the calixarene, for para-sulfonatocalix[4]arene there is 17.6° displacement between the axes of the two motifs generating a laminate structure.

A family of amphiphilic cyclodextrins (6, 7) has been prepared through 6-S-alkylation (alkyl=n-dodecyl and n-hexadecyl) of the primary side and 2-O-PEGylation of the secondary side of alpha-, beta-, and gamma-cyclodextrins (PEG=poly(ethylene glycol)). These cyclodextrins form nonionic bilayer vesicles in aqueous solution. The bilayer vesicles were characterized by transmission electron microscopy, dynamic light scattering, dye encapsulation, and capillary electrophoresis. The molecular packing of the amphiphilic cyclodextrins was investigated by using small-angle X-ray diffraction of bilayers deposited on glass and pressure-area isotherms obtained from Langmuir monolayers on the air-water interface. The bilayer thickness is dependent on the chain length, whereas the average molecular surface area scales with the cyclodextrin ring size. The alkyl chains of the cyclodextrins in the bilayer are deeply interdigitated. Molecular recognition of a hydrophobic anion (adamantane carboxylate) by the cyclodextrin vesicles was investigated by using capillary electrophoresis, thereby exploiting the increase in electrophoretic mobility that occurs when the hydrophobic anions bind to the nonionic cyclodextrin vesicles. It was found that in spite of the presence of oligo(ethylene glycol) substituents, the beta-cyclodextrin vesicles retain their characteristic affinity for adamantane carboxylate (association constant K(a)=7.1 x 10(3) M(-1)), whereas gamma-cyclodextrin vesicles have less affinity (K(a)=3.2 x 10(3) M(-1)), and alpha-cyclodextrin or non-cyclodextrin, nonionic vesicles have very little affinity (K(a) approximately 100 M(-1)). Specific binding of the adamantane carboxylate to beta-cyclodextrin vesicles was also evident in competition experiments with beta-cyclodextrin in solution. Hence, the cyclodextrin vesicles can function as host bilayer membranes that recognize small guest molecules by specific noncovalent interaction.A family of amphiphilic cyclodextrins (6, 7) has been prepared through 6-S-alkylation (alkyl=n-dodecyl and n-hexadecyl) of the primary side and 2-O-PEGylation of the secondary side of alpha-, beta-, and gamma-cyclodextrins (PEG=poly(ethylene glycol)). These cyclodextrins form nonionic bilayer vesicles in aqueous solution. The bilayer vesicles were characterized by transmission electron microscopy, dynamic light scattering, dye encapsulation, and capillary electrophoresis. The molecular packing of the amphiphilic cyclodextrins was investigated by using small-angle X-ray diffraction of bilayers deposited on glass and pressure-area isotherms obtained from Langmuir monolayers on the air-water interface. The bilayer thickness is dependent on the chain length, whereas the average molecular surface area scales with the cyclodextrin ring size. The alkyl chains of the cyclodextrins in the bilayer are deeply interdigitated. Molecular recognition of a hydrophobic anion (adamantane carboxylate) by the cyclodextrin vesicles was investigated by using capillary electrophoresis, thereby exploiting the increase in electrophoretic mobility that occurs when the hydrophobic anions bind to the nonionic cyclodextrin vesicles. It was found that in spite of the presence of oligo(ethylene glycol) substituents, the beta-cyclodextrin vesicles retain their characteristic affinity for adamantane carboxylate (association constant K(a)=7.1 x 10(3) M(-1)), whereas gamma-cyclodextrin vesicles have less affinity (K(a)=3.2 x 10(3) M(-1)), and alpha-cyclodextrin or non-cyclodextrin, nonionic vesicles have very little affinity (K(a) approximately 100 M(-1)). Specific binding of the adamantane carboxylate to beta-cyclodextrin vesicles was also evident in competition experiments with beta-cyclodextrin in solution. Hence, the cyclodextrin vesicles can function as host bilayer membranes that recognize small guest molecules by specific noncovalent interaction.

Alzheimer’s disease (AD) is characterized by extracellular deposits of amyloid β (Aβ) peptide and intracellular tau aggregates. Examination of these lesions in post-mortem brain tissue routinely provides a two-dimensional picture of the pathology with a limited depth of field. Several tissue-clearing protocols have been recently published [1, 4–6, 8, 10, 11, 16]. We compared the quality of immunostaining on post-mortem human brain tissues using several clearing techniques including CLARITY [4, 5], Scale [8], SeeDB [9], and 3DISCO [6]. Results were best with CLARITY. In that method, acrylamide hydrogel links the protein of the tissue and maintains its structure. Removing the lipids makes the block transparent and facilitates antibody diffusion [4, 5]. We noticed that the results were improved if ScaleA2 [8] was used to mount the block after CLARITY. Formalin-fixed frontal cortex samples from two controls and five AD individuals (Braak VI and Thal 5) were obtained from the Brain Bank GIE NeuroCEB with legal consent. Brain samples were cut at a thickness of 500 μm with a vibratome and were processed by the CLARITY technique [5]. Embedded in an acrylamide hydrogel constituted of 4 % paraformaldehyde (PFA), 4 % acrylamide, 0.25 % temperature-triggering initiator VA-044, PBS, the tissues were passively clarified at 37 °C for 2 weeks in the clearing solution (200 mM boric acid, 4 % w/v SDS, pH 8.5). The blocks were immunostained with a rabbit polyclonal anti-tau B19 antibody [3] and a mouse monoclonal anti-Aβ 4G8 antibody (Covance). Alexa Fluor® 488 goat anti-rabbit and Alexa Fluor® 568 goat anti-mouse antibodies (Life technologies) were used as secondary antibodies. For Aβ and neurofilament double immunohistochemistry, the tissues were first incubated with mouse monoclonal anti-neurofilament antibody (M0762 Dako) and then with Alexa Fluor® 568 goat anti-mouse antibody. After a blocking stage (10 % normal mouse serum), the tissues were incubated with biotin-labelled 4G8 anti-Aβ antibody (Covance), revealed with DyLight 488-labelled streptavidin (KPL, Eurobio, France). Triple staining (Aβ, tau and neurofilament) was also performed: the block was incubated with anti-tau B19 and anti-neurofilament M0762 antibodies revealed with the secondary Alexa Fluor® 488 goat anti-rabbit and Alexa Fluor® 568 goat anti-mouse antibodies. The third antibody was a biotin-labelled anti-Aβ 4G8 antibody (Covance) revealed with streptavidin-Alexa 405 (Life technology). The mounting protocol was modified from the original method: we added a fixation step (4 % PFA in PBS for 15 min) at the end of the procedure to improve the stability of the immunostaining, and an incubation step (0.2 M glycine for 15 min) to quench autofluorescence. We used ScaleA2 solution as mounting medium [8], instead of 80 % glycerol or FocusClear described in the original method [5]. ScaleA2 increased the transparency of the tissue compared to 80 % glycerol, lowered the cost of the experiment compared to FocusClear and shortened incubation time (overnight compared to 2 days). The immunolabellings were analysed with an upright confocal microscope (Olympus Fluoview Fv1000). The Z-stack images were re-constructed using Imaris software (Bitplane). The volume of the “clarified” block was increased by approximately 40 % after passive removal of the lipids. While 80 % glycerol or FocusClear restored the volume in the original CLARITY technique, ScaleA2 further increased it but kept the morphological quality of the technique. The combination of CLARITY and ScaleA2 is not appropriate for stereological measures because of the volume expansion. Despite the increase in volume, the axons (shown by neurofilament immunostaining) remained continuous (Supplementary 10.1007/s00401-014-1322-y). The clarified tissues were fully transparent. The video, obtained with confocal microscopy, provides a 3-D view of the lesions revealed by Aβ and tau immunohistochemistry (10.1007/s00401-014-1322-y). Amyloid deposits appeared to have diverse 3-D structure in AD brains: some deposits were dense and focal; some diffuse deposits appeared hollow (10.1007/s00401-014-1322-y). Accumulation of Aβ was regularly spaced in clumps throughout the cortex (10.1007/s00401-014-1322-y). Tau accumulated in segmented and discontinuous neuritic processes. Many dystrophic neurites were associated with dense, focal, presumably “mature” Aβ focal deposits [2]. Plaque-induced distorted neurites have been previously reported by in vivo observation in AD transgenic animal [7, 12, 13, 15] and in the affected areas of post-mortem human AD brains [10, 14]. Our video of Aβ and neurofilament double immunostaining showed the persistence of a large number of axons, one of them (traced in yellow) deflected by the focal deposits (10.1007/s00401-014-1322-y). Finally, a triple immunostaining for Aβ (blue), tau (green) and neurofilament (red) showed that the tangle bearing neuron that we identified had no visible axonal projection (10.1007/s00401-014-1322-y). The region of the Aβ focal deposit contained few axons. The Aβ immunoreactivity (revealed with an avidin biotin amplification step) was excellent through the whole thickness of the block. Neurofilament and tau immunoreactivities (revealed with no amplification step) were stronger in a 150-µm-thick layer at the top of the block. The transparency of the block was, however, homogeneous. The 150-µm-thick layer of high immunoreactivity was detected at the top and at the bottom of the block: it was not related to a defect in the penetration of the laser beam during the imaging process but to better antibody penetration near the surface. Longer incubation time, higher concentration of detergent in the buffer and various amplification systems will be tested in the future to improve the homogeneity of the signal throughout the thickness of the sample. These first results uncover the 3-D architecture of AD lesions and demonstrate the utility of the CLARITY technique in studying the distribution of AD pathology in 3-D, even in post-mortem human tissue.

The organic semiconductor dibenzotetrathiafulvalene (DB-TTF) presents, at ambient conditions, four polymorphic modifications. In addition to the already known monoclinic structure (a) with Z ¼ 2, we have resolved by single crystal X-ray diffraction (XRD) a second crystal structure (b), also monoclinic but with Z ¼ 4. Two other polymorphic modifications (g and d) have been found by means of lattice phonon confocal Raman microscopy and XRD. In this paper we present a series of growth experiments, from vapour or from solution, in films and in the bulk phase, describing the variety of transformations which occur among the different phases and their mixing, also at a micrometric scale. Quasi harmonic lattice dynamics calculations satisfactorily reproduce the structures of the a and the b polymorphs and help the phonon assignment of polarized Raman spectra in single crystals.

International audience; In an effort toward the visualization of β-amyloid plaques by in vivo imaging techniques, we have conjugated an optimized derivative of the Pittsburgh compound B (PiB), a well-established marker of Aβ plaques, to DO3A-monoamide that is capable of forming stable, noncharged complexes with different trivalent metal ions including Gd3+ for MRI and 111In3+ for SPECT applications. Proton relaxivity measurements evidenced binding of Gd(DO3A-PiB) to the amyloid peptide Aβ1-40 and to human serum albumin, resulting in a two- and four-fold relaxivity increase, respectively. Ex vivo immunohistochemical studies showed that the DO3A-PiB complexes selectively target Aβ plaques on Alzheimer's disease human brain tissue. Ex vivo biodistribution data obtained for the 111In-analogue pointed to a moderate blood-brain barrier (BBB) penetration in adult male Swiss mice (without amyloid deposits) with 0.36% ID/g in the cortex at 2 min postinjection.

International audience; Although cholesterol has been involved in the pathophysiology of Alzheimer disease (AD), its distribution in the cerebral cortex over the course of AD is unknown. We describe an original method to quantify cholesterol distribution using time-of-flight secondary ion mass spectrometry imaging. Cholesterol was unevenly distributed along the cortical thickness, being more abundant close to the white matter, in both control and AD cases. However, the mean cholesterol signal was significantly higher in the lower half of the cortex in AD samples compared to controls. This increase, when converted into cortical layers, was statistically significant for layers III and IV and did not reach significance in layers V + VI, the variability being too high at the interface between grey and white matter. The density of neurofibrillary tangles and of senile plaques was not statistically linked to the abundance of cholesterol. Cholesterol overload thus appears a new and independent alteration of AD cerebral cortex. The structure in which cholesterol accumulates and the mechanism of this accumulation remain to be elucidated.

The crystallization of an organic semiconductor, viz., tetrahexil-sexithiophene (H4T6) molecules, confined into nanosized cavities of a self-organized polystyrene beads template, has been investigated by means of in situ grazing incidence X-ray diffraction measurements, during the solvent evaporation. Thanks to these real time experiments, the phase content and the crystalline domain orientation of H4T6 have been determined, from the onset of the first crystalline molecular assembly to the stable system. The correlation between the bead size dependent crystallization mechanism in this complex system and the enhanced transistor performance has been established. These results, which can be extended to a wide range of organic materials, are useful for developing an attractive sustainable process for fabrication of organic devices with enhanced performance.

The calix[4]arene dihydroxyphosphonic acid-1,10-phenanthroline complex shows caging of the guest molecules as a pi-pi stacked dimer in a cavity formed by intermolecular hydrogen bonds and aromatic walls formed by the calixarene.

Design, synthesis, and multifunctionality of p-octiphenyl beta-barrel pores with external LRL triads and internal HH dyads are described. Molecular recognition of anionic fullerenes > calixarenes > pyrenes by guanidinium arrays at the outer pore surface is shown to result in pore opening, whereas alpha-helix recognition within the topologically matching internal space is shown to result in noncompetitive pore blockage. This experimental evidence for multifunctionality is supported by comparison with pertinent control pores and blockers, by structural studies using FRET from p-octiphenyl donors in the pore to BODIPY acceptors in the bilayer, and by molecular mechanics simulations. Practical usefulness of ligand-gated synthetic multifunctional pores is exemplified with the continuous detection of chemical processes.Design, synthesis, and multifunctionality of p-octiphenyl beta-barrel pores with external LRL triads and internal HH dyads are described. Molecular recognition of anionic fullerenes > calixarenes > pyrenes by guanidinium arrays at the outer pore surface is shown to result in pore opening, whereas alpha-helix recognition within the topologically matching internal space is shown to result in noncompetitive pore blockage. This experimental evidence for multifunctionality is supported by comparison with pertinent control pores and blockers, by structural studies using FRET from p-octiphenyl donors in the pore to BODIPY acceptors in the bilayer, and by molecular mechanics simulations. Practical usefulness of ligand-gated synthetic multifunctional pores is exemplified with the continuous detection of chemical processes.

We report that the efflux of 5(6)-carboxyfluorescein anions from neutral egg yolk phosphatidylcholine vesicles is mediated by oligo/polyarginines only in the presence of activating amphiphilic anions. Screening of anion activators reveals best synergism for amphiphilic carboxylates (fullerene > calix[4]arene approximately coronene > pyrene > calix[6]arene > alkyl), whereas amphiphilic sulfates show less satisfactory activation despite often lower effective concentrations. The analogous alcohols and one calix[4]arene diphosphate were inactive. These results are discussed in the context of a tentative anion carrier mechanism, where interactions with bilayer (interface-directed translocation) and carrier (arene-templated carboxylate-guanidinium pairing) contribute to activator efficiencies. Applied to HeLa cells, pyrenebutyrate is shown to significantly increase the uptake of a fluorescently labeled octaarginine in a concentration-dependent manner.We report that the efflux of 5(6)-carboxyfluorescein anions from neutral egg yolk phosphatidylcholine vesicles is mediated by oligo/polyarginines only in the presence of activating amphiphilic anions. Screening of anion activators reveals best synergism for amphiphilic carboxylates (fullerene > calix[4]arene approximately coronene > pyrene > calix[6]arene > alkyl), whereas amphiphilic sulfates show less satisfactory activation despite often lower effective concentrations. The analogous alcohols and one calix[4]arene diphosphate were inactive. These results are discussed in the context of a tentative anion carrier mechanism, where interactions with bilayer (interface-directed translocation) and carrier (arene-templated carboxylate-guanidinium pairing) contribute to activator efficiencies. Applied to HeLa cells, pyrenebutyrate is shown to significantly increase the uptake of a fluorescently labeled octaarginine in a concentration-dependent manner.

The crystal structures of calix[4]arene di-methoxycarbonyl-methyl ester and carboxylic acid have been resolved. Interestingly, the packing for both molecules is in the form of crystal symmetry defined hexagonal helical nanotube architecture, but with the methyl ester derivative showing an extended form of the helix with regard to that formed by the carboxylic acid derivative. The addition of one carbon in the ester group leads to inclusion of the ethyl ester within a neighbouring calixarene cavity, and in consequence the packing becomes radically different.

The elusive questions how arginine-rich sequences allow peptides and proteins to penetrate cells or to form voltage-gated ion channels are controversial topics of current scientific concern. The possible contributions of exchangeable counterions to these puzzling processes remain underexplored. The objective of this report is to clarify scope and limitations of certain counteranions to modulate cellular uptake and anion carrier activity of oligo/polyarginines. The key finding is that the efficiency of counteranion activators depends significantly on many parameters such as activator-membrane and activator-carrier interactions. This finding is important because it suggests that counteranions can be used to modulate not only efficiency but also selectivity. Specifically, activator efficiencies are found to increase with increasing aromatic surface of the activator, decreasing size of the transported anion, increasing carrier concentration as well as increasing membrane fluidity. Efficiency sequences depend on membrane composition with coronene > pyrene >fullerene > calix[4]arene carboxylates in fluid and crystalline DPPC contrasting to fullerene > calix[4]arene approximately coronene > pyrene carboxylates in EYPC with or without cholesterol or ergosterol. In HeLa cells, the efficiency of planar activators (pyrene) exceeds that of spherical activators (fullerenes, calixarenes). Polyarginine complexes with pyrene and coronene activators exhibit exceptional excimer emission. Decreasing excimer emission with increasing ionic strength reveals dominant hydrophobic interactions with the most efficient carboxylate activators. Dominance of ion pairing with the inefficient high-affinity sulfate activators is corroborated by the reversed dependence on ionic strength. These findings on activator-carrier and activator-membrane interactions are discussed as supportive of arene-templated guanidinium-carboxylate pairing and interface-directed translocation as possible origins of the superb performance of higher arene carboxylates as activators.The elusive questions how arginine-rich sequences allow peptides and proteins to penetrate cells or to form voltage-gated ion channels are controversial topics of current scientific concern. The possible contributions of exchangeable counterions to these puzzling processes remain underexplored. The objective of this report is to clarify scope and limitations of certain counteranions to modulate cellular uptake and anion carrier activity of oligo/polyarginines. The key finding is that the efficiency of counteranion activators depends significantly on many parameters such as activator-membrane and activator-carrier interactions. This finding is important because it suggests that counteranions can be used to modulate not only efficiency but also selectivity. Specifically, activator efficiencies are found to increase with increasing aromatic surface of the activator, decreasing size of the transported anion, increasing carrier concentration as well as increasing membrane fluidity. Efficiency sequences depend on membrane composition with coronene > pyrene >fullerene > calix[4]arene carboxylates in fluid and crystalline DPPC contrasting to fullerene > calix[4]arene approximately coronene > pyrene carboxylates in EYPC with or without cholesterol or ergosterol. In HeLa cells, the efficiency of planar activators (pyrene) exceeds that of spherical activators (fullerenes, calixarenes). Polyarginine complexes with pyrene and coronene activators exhibit exceptional excimer emission. Decreasing excimer emission with increasing ionic strength reveals dominant hydrophobic interactions with the most efficient carboxylate activators. Dominance of ion pairing with the inefficient high-affinity sulfate activators is corroborated by the reversed dependence on ionic strength. These findings on activator-carrier and activator-membrane interactions are discussed as supportive of arene-templated guanidinium-carboxylate pairing and interface-directed translocation as possible origins of the superb performance of higher arene carboxylates as activators.

Amphiphilic calixarenes represent a promising class of derivatives, potentially useful for transporting molecules because of their ability to self-organize as Solid Lipid Nanoparticles in water. The current study shows that after derivatization of the para-H-calix[4]arene with hexanoyl chains, the resultant amphiphilic calixarenes retain their properties to complex small organic molecules. The solid structures of the complexes of para-hexanoyl-calix[4]arene with methanol, dimethylformamide-methanol, dimethyl sulfoxide-methanol and nitrobenzene are reported. As for the p-tert-butyl calix[4]arene, aliphatic guests are stabilized by a variety of short-range interactions including C-H[small pi] or [small pi]-[small pi] interactions. Moreover, the presence of the grafted hydrophobic chains generates an extension of the hydrophobic calixarene cavity and thus provides another site where complexation can take place. The structures show that the geometry of the hexanoyl chains is modified by the presence of the guest molecules and that the chains fold over to aid encapsulation of the guest.

Organic field effect transistors (OFET), where ordered conjugated molecules act as charge transport material, are low-dimensional devices. Charge carriers are transported within the first few mono-layers in contact with the gate dielectric. The structural/morphological and electronic control of the first few monolayers of the organic semiconductor (e.g. pentacene) allows us to fabricate ultra-thin film transistors with the accumulation layer directly exposed to the outer environment. We developed OFETs as label-free biological transducers and sensors of biological systems. Unconventional patterning techniques and microfluidics have been adapted to proteins and nucleic acids to dose the molecules on the OFET channel with a high control of the concentration. Patterning is useful to impart conformations and architectures which are otherwise not accessible spontaneously by the biological systems.Operations an ultra-thin film OFETs under water will be shown, together with the response of OFET parameters to different biomolecules (linear DNA, beta-amyloid 1-40 peptide) upon a systematic change of concentration, secondary structure, aggregation state. The sensitivity issues will be addressed. These results show a quantitative approach for the detection of biological molecules in vitro and monitoring their slow dynamics. Finally, first experiments using OFETs transducers of cell signaling at the molecular level will be presented in the presence of diffentiated murine stem cells NE4C forming neural networks. References: [1] P. Stoliar, E. Bystrenova, M. Facchini, P. Annibale, M.-J. Spijkman, S. Setayesh, D. de Leeuw, and F. Biscarini, “DNA adsorption measured with ultra-thin film organic field effect transistors” Biosens. Biolectronics 29, 2935-2938 (2009).[2] A. Shehu et al. submitted 2009. [3] E. Bystrenova, M. Jelitai, I. Tonazzini, A. Lazar, M. Huth, P. Stoliar, C. Dionigi, M. G. Cacace, B. Nickel, E. Madarasz, and F. Biscarini “Neural networks grown on organic semiconductors”, Adv. Funct. Mater. 18, 1751-1756 (2008).