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Supramolecular nanocontainers based on monocationic and gemini surfactants and oppositely charged polyelectrolytes (polyacrylic acid, polyethyleneimine) for the stabilization and enhancement of solubility of hydrophobic quantum dots CdSe/ZnS were formed. The size (from 2 to 70 nm depending on the type of nanocontainers) and shape of aggregates containing quantum dots were determined by transmission electron microscopy. It was shown that the nature of the stabilizing agent influences the morphology of aggregates. The increase in photostability of quantum dots in micellar solutions of gemini surfactants and the possibility of their preservation in the polyelectrolyte capsules are identified.

Here we represent the first example of the formation of mixed nanoscale associates, constructed from amphiphilic calixresorcinarenes and hydrophobic carboxylic acids including drugs. The amidoamino-calixresorcinarene self-associates effectively solubilize hydrophobic carboxylic acids - drugs such as naproxen, ibuprofen, ursodeoxycholic acid and aliphatic dodecanoic acid - with the formation of the mixed aggregates with the macrocycle/substrate stoichiometry from 1/1 to 1/7. The ionization of organic acids and the peripheral nitrogen atoms of the macrocycles with the subsequent inclusion of hydrophobic acids into the macrocycle self-associates is the driving force of solubilization. In some cases, this leads to the co-assembly of the macrocycle polydisperse associates into supramolecular monodisperse nanoparticles with the diameter of about 100 nm. The efficiency of drug loading into the nanoparticles is up to 45% and depends on the structure of organic acid. The dissociation of the mixed aggregates and release of organic acid are attained by decreasing pH.

Here, we report a novel approach of using a supramolecular system based on calix[4]resorcinarene and surfactant to facilitate the release of hydrophobic compounds. This finding is an important step towards the development of controlled-release formulations for water-insoluble drugs.

The work introduces chemical and electrochemical synthetic routes to obtain Pd(0) nanoparticles (PdNPs) deposited onto silica supports in aqueous media. The former route is performed through reduction of Na 2 [PdCl 4 ] by ascorbic acid in the presence of amino-modified silica nanoparticles (SiO 2 –NH 2 ). The time-dependent variation of pH and the reductant concentration is the simple synthetic route to get uniform deposition of 215 nm sized silica supports by Pd(0) nanoparticles (3–10 nm). The methylviologen-mediated electrochemical synthetic route results in small PdNPs (3–9 nm) located both onto and beyond the silica supports. Thus, the chemical synthetic route provides more homogeneous Pd(0)–SiO 2 –NH 2 aqueous colloids. The results reveal that attractive interactions of amino/ammonium groups of SiO 2 –NH 2 with both [PdCl 4 ] 2− and ascorbate-stabilized Pd(0) seeds are the key reasons for the better Pd(0)-deposition onto silica supports. The chemically deposited Pd(0)–SiO 2 –NH 2 nanoparticles catalyze the chemiluminescence of luminol resulted from the H 2 O 2 -facilitated oxidation in alkaline aqueous solutions.

New water-soluble pectin complexes with Ca(2+), Mg(2+), Co(2+), Cu(2+), Fe(2+), Mn(2+), Zn(2+) on the basis of pectin biopolymer have been synthesized and successfully tested on white rats. For a starting, we have obtained a sodium pectate to enhance solubility of target complexes as a whole. Shortly afterwards, running the reaction of ligand exchange of Nа(+) ions with corresponding s-, d- metal cations we were able to synthesize new pectin complexes. The ranges of s-, d-metals salts concentrations were detected experimentally, in which the selective formation of water-soluble complexes occurred. Antianemic effect of new pectin complexes with Na, Fe and Na, Ca, Fe was investigated on white rats with posthemorrhagic anemia. Under the effect of complexes, the improvement of animals and prevention of erythropoiesis disorders were observed. Antianemic effect of the complexes manifested itself in the doses equivalent to 25% or 50% of the iron daily rate, recommended in the treatment of iron-deficiency anemia with the drugs based on iron sulphate.

The synthesis of small (2–3 nm) silver nanoparticles in the presence of new amidoaminocarboxylic tetrapentylcalix[4]resorcinarene and the binding of the antitumor drug Doxorubicin by a macrocycle in solution and on the surface of nanoparticles are described.

The new cationic surfactants containing octyl and dodecyl carbamate moiety in the head group and hexadecyl tail were synthesized and characterized. They demonstrate versatile self-assembling behavior strongly controlled by structural characteristics of amphiphilic molecules. The octyl derivative at a concentration of 0.06 mM forms micelles, which can undergo structural rearrangement with the increase of surfactant content in the solutions (above 0.01 M). Compound with a dodecyl substituent, upon reaching a critical concentration, forms large aggregates without passing through the micellar stage. Combination of different techniques makes it possible to assume that morphological transitions between micelles and vesicles probably occurs with the variation in structural characteristics and concentration of surfactants. This is supported by dynamic light scattering and transmission electron microscopy, as well as changes in characteristics of spectral probes sensitive to micropolarity and packing parameters of aggregates. Aggregates formed showed high solubilization capacity, exceeding that of typical cationic micelles, toward Orange OT hydrophobic dye and poorly water soluble anti-inflammatory drugs, indomethacin and meloxicam. Carbamate-containing surfactants demonstrated the ability to penetrate through cell membrane, delivering the solubilized hydrophobic substances into the cell, which was testified by flow cytometry and fluorescence microscopy with DAPI and Nile Red dyes.

The growing resistance of bacteria to traditional antibiotics makes it necessary to develop new antimicrobial agents with the dissimilar mode of action such as Ag and AgCl nanoparticles. Here the synthesis of silver NPs in the colloidal solutions of calix[4] resorcinarene-mPEG conjugate C11-mPEG was reported. NPs were synthesized under varied conditions: different Ag+/C11-mPEG molar ratio, presence/absence of reducing agent (NaBH4), in dark or LED light exposure. It was found that in all cases Ag-AgCl NPs, stabilized by C11-mPEG, were obtained with the difference in the Ag NPs content and sizes. Physicochemical characteristics of the Ag-AgCl@C11-mPEG NPs were evaluated by UV–vis, FT-IR, XRPD, XRF, DLS, and TEM methods. The antimicrobial activity of NPs against Gram-positive and Gram-negative bacteria and fungi was studied and the preferred antimicrobial activity against Gram-positive bacteria was found. The proposed scheme of Ag-AgCl@C11-mPEG NPs and the influence of NPs content on the antimicrobial activity were discussed.

The synthesis of colloidal platinum nanoparticles (PtNPs) (dcore≈1-40 nm) in an aqueous solution was carried out using amido(dimethyl)amino- and carboxy- calix[4]resorcinarenes with alkyl substituents on the lower rim as stabilizer. The nanoparticles were characterized by spectrophotometry, IR, TEM, DLS, PXRD and SAXS. It was shown that PtNPs and gold nanoparticles (AuNPs) obtained, stabilized by calix[4]resorcinarenes, demonstrate the photocatalytic activity in the photodegradation of methyl orange and rhodamine B toxic dyes under visible light irradiation. The rate constants of catalytic reaction (K1, min−1) and activity of nanocatalysts (K2, min−1 mol−1) were calculated. It was found that size of metal core, structure of macrocycle stabilizing the surface of metal nanoparticles, its ability to form self-associates and bind dye molecules define the rate of dye photodegradation reaction. The study of the interaction of PtNPs and AuNPs capped with amidoamine macrocycles with organic photolinkers by spectrophotometry and fluorescence showed the binding of photolinkers by macrocycles, PtNPs and AuNPs. The photocatalytic activity of obtained cooperative nanoassociates was studied. The addition of photolinkers leads to both an increase and a decrease in the reaction rate, depending on the structure of linker and macrocycle. An increase in the reaction rate occurs due to the formation of photoactive supramolecular nanoassociates and the additional photosensitizing action of the photolinker on the surface of a metal nanoparticle. Such hybrid nanocatalysts based on metal nanoparticle and calixresorcinarenes have the potential to be used in the field of effective photodegradation of toxic water pollutants.

Complexation ability of homologous series of amphiphiles bearing imidazolium and urethane moieties (IAC-n, n = 14, 16, 18) toward bovine serum albumin (BSA) has been investigated by various physico-chemical methods (tensiometry, fluorescence spectroscopy, spectrophotometry, dynamic and electrophoretic light scattering, circular dichroism, and transmission electron microscopy). It has been revealed, that aggregation thresholds of systems based on IAC-n could be 5–8-fold reduced by BSA addition. Fluorescent analysis allows to estimate that binding of components is favorably mediated by tryptophan amino acid residues and is driven by different forces depending on the length of amphiphile hydrophobic tail. In particular, dominate contribution of Van der Waals interactions to the complexation has been shown in the case of IAC-14 and IAC-16, while hydrophobic interactions prevailed for IAC-18. It has been demonstrated that amphiphile addition causes reversible unfolding of protein macromolecules in all cases. Spectrophotometry assay exhibits that amphiphile/BSA complexes have more significant solubilization capacity toward hydrophobic guest in comparison with individual IAC-n systems.

The work introduces regularities and driving forces of self-assembly of hexarhenium clusters [{Re6S8}L6]n− (L = SO32−, CN−, OH−) with [AgL′]+ (L′ = pyridine-2-ylphospholane) produced by dissociation of [Ag2L′2]2+ in aqueous solutions. The formation of nano-sized Re6 Ag assemblies is detected by the spectral measurements in the solutions and by the solid-state analysis of the separated colloids. The nature of L is highlighted as the main factor affecting the assembly. The poor affinity of the SO32− ligands to Ag+ restricts the assembly of [{Re6S8}(SO3)6]10− with the silver(I) complexes. [{Re6S8}(OH)6]4− is more promising candidate for the heterometallic assembly contributed by both counter-ion binding and coordination bonds, while the efficient coordination of Ag+ via the nitrogen of the cyanide ligands of [{Re6S8}(CN)6]4− is the main driving force for the Re6 Ag assembly. The stronger impact of [Ag2L′2]2+ relative to Ag+ cations on the formation of Re6 Ag assemblies in aqueous solutions, as well as the presence of L′ in the separated colloidal phase, indicate the important role of the L′ ligand in the studied supramolecular systems. The cluster-centered luminescence serves as signaling system at the binding of glutathione, cysteine and dithiothreitol with Ag+ ions of the heterometallic assemblies. The assemblies based on [{Re6S8}(CN)6]4− are able to discriminate glutathione versus cysteine, while the assemblies formed by [{Re6S8}(OH)6]4− give the unselective luminescence response on the both biothiols at the concentration level of 2 μM.

The synthesis of new conjugates of calix[4]resorcinarenes and methoxy-PEG via acylhydrazone bonds and their study in the formation of pH-sensitive low-toxic supramolecular drug delivery systems have described. The syntheses have been performed on the base of two calix[4]resorcinarenes in chair and boat conformations to obtain the dendrimer-like and amphiphilic conjugates, respectively. The structures of the conjugates have been confirmed by 1H, 13C NMR, and FT-IR spectroscopy, Maldi-TOF mass spectroscopy, and SLS method. The self-association of both amphiphilic and dendrimer-like conjugates has been found (NMR FT-PGSE, fluorimetry, DLS and TEM methods). The hydrolysis of the conjugates at pH 5.5 (proved by 1H NMR and FT-IR spectroscopy, DLS method) lead to the improved release of the conjugate-encapsulated Dox. The low hemolytic activity and low cytotoxicity against Chang liver cells of the conjugates and products of their hydrolysis have been demonstrated. Meanwhile, the improved cytotoxicity and photodynamic activity of conjugates-encapsulated drugs (Dox and Methylene Blue, respectively) has been found in vitro. The results have indicated the potential using of the calix[4]resorcinarene-mPEG conjugates bearing acylhydrazone bonds as supramolecular drug delivery systems.

In the framework of this report the bottom-up strategy has been used for the development of novel soft nanocontainers through self-assembly of homologous series of newly synthesized amphiphilic compounds of N-(2-ethylaminocarbonyloxyethyl)-N-alkylimidazolium bromides. Their aggregation properties, solubilization capacity, antimicrobial activity, membranotropic properties and capability to form lipoplexes have been investigated. Using various physico-chemical techniques it has been demonstrated that introduction of urethane moiety into amphiphile structure results in the 2-3-fold decrease of critical micelle concentration in comparison with their unsubstituted counterparts. It has been suggested, that interaction of amphiphiles with DNA decamer is predominantly driven by cooperative electrostatic interactions. Membranotropic properties of novel amphiphiles could be regulated by the change of the length of hydrophobic tail; with these properties being the more markedly expressed in the case of the lower homologue. Estimation of antimicrobial activity against several strains of microorganisms has revealed, that these amphiphiles were by several-fold more active toward Staphylococcus aureus, Bacillus cereus bacteria and Candida albicans fungi in comparison with reference compounds – norfloxacin and ketoconazole. Hemolytic activity of these amphiphiles has not exceeded 0.9% under bactericide and bacteriostatic concentrations. The combination of advanced characteristics allows us to recommend these amphiphiles for fabrication of soft materials with the wide spectrum of practically useful properties like effective nanocontainers for drug and gene delivery, capable of crossing the cell membrane, and harmless for human agents against pathogenic microorganisms.

The present work introduces ternary Ln(III) (Ln = Eu, Yb, Lu) complexes with thenoyltriflouro1,3-diketonate (TTA−) and phosphine oxide derivative (PhO) as building blocks for core-shell nanoparticles with both Eu(III)- or Yb(III)-centered luminescence and the dual Eu(III)-Yb(III)-centered luminescence. Solvent-mediated self-assembly of the complexes is presented herein as the procedure for formation of Eu Lu, Eu Yb and Yb Lu heterometallic or homometallic cores coated by hydrophilic polystyrenesulfonate-based shells. Steady state and time resolved Eu-centered luminescence in homolanthanide and heterolanthanide Eu Lu and Eu Yb cores is affected by Eu → Eu and Eu → Yb energy transfer due to a close proximity of the lanthanide blocks within the core of nanoparticles. The Eu → Yb energy transfer is highlighted to be the reason for the enhancement of the NIR Yb-centered luminescence. Efficient cellular uptake, low cytotoxicity towards normal and cancer cells, and sensing ability of Eu Yb nanoparticles on lomefloxacin additives via both red and NIR channels make them promising as cellular imaging agents and sensors.

The work is aimed at solving the problem of finding a promising alternative to indium tin oxide as an optically transparent electrode used in many modern devices such as solar cells, touch screens, transparent triboelectric generators, etc. In this paper, we propose the use of an original method for synthesizing oriented metal nano networks to create an electrically conductive layer on a surface of a glass substrate. Due to the orientation of metal networks, it is possible to significantly reduce the use of metal and increase open areas of the coating, which leads to preservation of electrical conductivity of the coating with a high degree of transparency. The method of depositing the proposed coating is based on the method of chemical precipitation from a liquid using a self-organized micellar template.

The present work introduces the optimization of the oxidative degradation, complex formation and aggregation of the water-soluble metal oxide nanostructures (the so-called keplerates) [{W6O21(H2O)5(OAc)0.5}12{Mo2O4(OAc)}30]48− (W72Mo60), [{Mo6O21(H2O)3(SO4)}12(VO)30(H2O)20]26− (Mo72V30), and [{Mo6O21}12Fe30(OAc)12{Mo2O7(H2O)}2{H2Mo2O8(H2O)}(H2O)91] (Mo72Fe30) in aqueous solutions containing Gd3+ ions and triblock copolymers, which can be used as a tool to enhance magnetic relaxivity of the gadolinium-bound nanostructures. The particularly significant enhancement in the magnetic relaxivity of the Gd3+ ions bound with W72Mo60 versus Mo72Fe30/V30 is due to the more convenient size of the external pores in the keplerate framework, which are the binding sites for Gd3+ aqua ions. The structure of the W72Mo60 keplerate is also responsible for the high stabilities of its gadolinium complexes against oxidative degradation in the solutions. The aggregation of the gadolinium-bound W72Mo60 keplerates controlled by the Gd:keplerate molar ratio is a factor in addition to the structure affecting the relaxivity. The assembly of the gadolinium-bound keplerates with the triblock copolymers enhances the relaxivity values by limiting the size of the aggregates, while the relaxivity of the molecular complexes is insignificantly affected by the assembly with the triblock copolymers. The gadolinium complexes exhibiting competitively high magnetic relaxivity values, coupled with their high chemical stability and low cytotoxicity, are introduced herein as the result of the structural optimization, both on molecular and supramolecular levels.

In the present work, we have prepared the $$\sim $$ 10 nm superparamagnetic iron-oxide nanoparticles by means of high-temperature decomposition of iron oleate precursor. Then they were coated with silica shell to impart water-solubility and an ability to accommodate paramagnetic Gd(III)-based complexes inside silica coating. All of the prepared nanoparticles form stable in time aqueous dispersions and show good negative or/and positive contrasting effect at different magnetic field strengths (0.47, 1.41, 14.1 T). It has been also exemplified that the incorporation of [Gd(TCAS)] complexes into silica shell triggers a significant increase of the transverse relaxivity of the core–shell nanoparticles. The correlation between relaxometric properties and morphology of the obtained nanoparticles was revealed. The non-toxicity of the obtained nanoparticles along with their ability to shorten both transverse and longitudinal relaxation rates of water protons make them good candidates for their use as dual-mode contrast agents in MRI.

New mixed cationic liposomes based on L-{\alpha}-phosphatidylcholine and dihexadecylmethylhydroxyethylammonium bromide (DHDHAB) were designed to overcome the BBB crossing by using the intranasal route. Synthesis and self-assembly of DHDHAB were performed. A low critical association concentration (0.01 mM), good solubilization properties toward hydrophobic dye Orange OT and antimicrobial activity against gram-positive bacteria Staphylococcus aureus (MIC=7.8 {\mu}g.mL-1) and Bacillus cereus (MIC=7.8 {\mu}g.mL-1), low hemolytic activities against human red blood cells (less than 10%) were achieved. Conditions for preparation of cationic vesicle and mixed liposomes with excellent colloidal stability at room temperature were determined. The intranasal administration of rhodamine B-loaded cationic liposomes was shown to increase bioavailability into the brain in comparison to the intravenous injection. The cholinesterase reactivator, 2-PAM, was used as model drug for the loading in cationic liposomes. 2-PAM-loaded cationic liposomes displayed high encapsulation efficiency (~ 90 %) and hydrodynamic diameter close to 100 nm. Intranasally administered 2-PAM-loaded cationic liposomes were effective against paraoxon-induced acetylcholinesterase inhibition in the brain. 2-PAM-loaded liposomes reactivated 12 +/- 1% of brain acetylcholinesterase. This promising result opens the possibility to use marketed positively charged oximes in medical countermeasures against organophosphorus poisoning for reactivation of central acetylcholinesterase by implementing a non-invasive approach, via the "nose-brain" pathway.

The authors describe new ligands with two 1,3-diketone groups and two heteroaromatic (pyridyl or quinolyl) moieties embedded to the upper and lower rims of dibromo-substituted calix[4]arene scaffold. The ligands bind Tb(III) ions in alkaline DMF solutions to form 1:1 complexes. The strong Tb(III)-centered luminescence (with excitation/emission peaks at 330/545 nm) of the complexes results from efficient ligand-to-metal energy transfer. The complexes were incorporated into polystyrenesulfonate (PSS) colloids by diluting a DMF solution of the complex with aqueous solution of PSS. The luminescence of the colloids is quenched by copper(II), and this was used to develop a method for its fluorometric determination in nanomolar concentrations. The lower limit of detection is 0.88 nM. Quenching is a result of (a) ion exchange which converts the terbium complexes into their copper counterparts, and (b) energy transfer from Tb(III) to Cu(II) complexes. The low cytotoxicity of the colloidal nanoprobe conceivably makes it a promising tool for use in cellular imaging. Graphical abstract New calix[4]arene derivative provide efficient binding sites for Tb(III) and Cu(II) ions. The Tb(III) complexes were embedded to core-shell nanoparticles by solvent-mediated aggregation followed by polystryrenesulfonate deposition. The nanoparticles exhibit luminescence response on copper ions in nanomolar concentration range.

The efficient catalysis of oxidative alkylation and fluoroalkylation of aromatic C-H bonds is of paramount importance in the pharmaceutical and agrochemical industries, and requires the development of convenient Ag-0-based nano-architectures with high catalytic activity and recyclability. We prepared Ag-doped silica nanoparticles (Ag0/+@SiO2) with a specific nano-architecture, where ultra-small sized silver cores are immersed in silica spheres, 40 nm in size. The nano-architecture provides an efficient electrochemical oxidation of Ag+@SiO2 without any external oxidant. In turn, Ag+@SiO2 5 mol% results in 100% conversion of arenes into their alkylated and fluoroalkylated derivatives in a single step at room temperature under nanoheterogeneous electrochemical conditions. Negligible oxidative leaching of silver from Ag0/+@SiO2 is recorded during the catalytic coupling of arenes with acetic, difluoroacetic and trifluoroacetic acids, which enables the good recyclability of the catalytic function of the Ag0/+@SiO2 nanostructure. The catalyst can be easily separated from the reaction mixture and reused a minimum of five times upon electrochemical regeneration. The use of the developed Ag-0@SiO2 nano-architecture as a heterogeneous catalyst facilitates aromatic C-H bond substitution by alkyl and fluoroalkyl groups, which are privileged structural motifs in pharmaceuticals and agrochemicals.

Cooperative nanoscale associates of amido(dimethylamino) calixresorcinarenes with pentyl (C5) and undecyl (C11) substituents on lower rim with antitumor drug-methotrexate (MTX) in aqueous solution and on the surface of gold nanoparticles C5@Au and C11@Au were formed. The formation of nanoparticles was investigated by 1H NMR, NMR FT-PGSE, 2D NOESY, DLS, TEM, spectrophotometry, fluorimetry. It was found that during the interaction of C5 or C11 macrocycles with MTX in aqueous solution, the latter generates dissociation of macrocycles self-associates with formation of cooperative macrocycle–MTX associates of smaller size due to multiple non-covalent interactions, which leads to increase in fluorescence intensity of MTX. In contrast, binding of MTX by macrocyclic associates preorganized as bilayer on surface of gold nanoparticles through electrostatic interactions induces aggregation of C5@Au-MTX or C11@Au-MTX associates, which results in quenching of MTX fluorescence in solution. Such particles have possible potential in the field of binding and delivery of antitumor drugs.

Methyl viologen MV2+ and tetraviologen calix[4]resorcinol MVCA-C 5 8+ with n-pentyl substituents in the resorcinol rings at potentials of MV2+/MV•+ and MVCA-C 5 8+ /MVCA-C 5 4•+ redox couples proved to be effective mediators of the electrochemical reduction of Ag+ ions in DMF/0.1 M Bu4NPF6. The potentiostatic nondiaphragm electrolysis at controlled mediator reduction potentials at room temperature using an Ag anode as an in situ supplier of Ag+ led to the formation of metallic silver nanoparticles in solution. The only resulting effect of electrolysis was the quantitative transfer of the metal anode into the metal nanoparticles in solution. In the case of MV2+, the nanoparticles aggregated into larger particles. MVCA-CC 5 8+ serves not only as a mediator, but also, to some extent, as a stabilizer of silver nanoparticles and can be recorded by a set of experimental methods.

The present work introduces an origin of sensing function of polyelectrolyte-coated colloids based on Tb(III) complexes with calix[4]resorcinarene cavitand bearing four 1,3 -diketone groups at the upper rim. The Tb(III)-centered luminescence of the colloids remains unchanged at pH 3–9, although the Tb(III) complexes are highly pH-dependent in DMF solutions. Both colloidal and luminescent properties of the colloids are stable within one month at least, which reveals stability of complex-based hard nanotemplates and soft polyelectrolyte deposition. The chelating substrates (catechol, tetracycline and fluoroquinolone derivatives) induce quick and reproducible luminescent response of the complex-based colloids without any detectable changes of their colloidal properties. The ternary complex formation at the interface of the colloids is the reason for their luminescent response on the substrates in aqueous solutions. Both the insolubility of the Tb(III)-containing cores and the shielding and/or buffer effect of the polyelectrolyte coating affect the interfacial complex formation, which results in more selective luminescent response of the colloids on the tetracycline and fluoroquinolone antibiotics in comparison with the complexes in solutions.

Efficient electrosynthesis of palladium(0) nanoparticles is carried out in solution by mediated electrochemical reduction of a complex dianion [PdCl4]2– in the DMSO/0.1 M Bu4NCl medium. The mediator function was performed by methylviologen and tetraviologen calix[4]resorcines MVCA-C 8+ with methyl (n = 1), n-pentyl (n = 5), and n-decyl (n = 10) substituents in resorcinol rings at the potentials of redox pairs MV2+/MV•+, MVCA-C 8+ /MVCA-C 4•+ . The resulting metal nanoparticles gradually aggregate to yield coarser particles. The smallest size (255 nm) have metal particles obtained in the presence of MVCA-C 5 8+ for the rest mediators, metal particles of the micron size are formed. Sonication results in disintegration of aggregates to nanoparticles.

The present work introduces the optimization of a synthetic procedure for oleate-coated iron-oxide nanoparticles by the thermal decomposition of Fe oleate dried at 30 and 70 °C in high-boiling organic solvents. The attention is focused on the temperature of the thermal decomposition, the nature of organic solvent, heating rate and the mode of the heating. In particular, heating on Wood alloy with simultaneous bubbling of argon through the reaction mixture versus the heating on mantel with magnetic stirring is highlighted as a route to improve the monodispersity of the nanoparticles. The effect of heating mode and rate on the nanoparticles size is estimated. The obtained tendencies point to the heating mode and rate as additional factors affecting the kinetic separation between nucleation and nanoparticle growth processes.

The present work introduces a novel route to sense the permeability of the polyelectrolyte layer deposited onto luminescent core. The use of ternary Eu(III) complexes as the luminescent core enables to detect the permeability of the polyelectrolyte layers through the change of the Eu(III)-centered luminescence. The chelating anions, such as adenosine phosphates, glutamic acid and ethylenediaminetetraacetic acid disodium salt were used as substrates. The origin of the fluorescent response is the complex formation of the substrates with the Eu(III) complexes, which is greatly affected by the equilibrium concentration of the substrates at the surface of the core. The latter in turn is influenced by the permeability of the polyelectrolyte layer. The obtained results highlight the impact of the nature of the exterior layer in the penetration of the substrates through the negatively and positively charged polyelectrolyte layers.

Nickel complexes of thiophosphorylated calix[4]resorcinols showed high catalytic activity for hydrogen evolution from acidic solutions and stability in the electro-assisted catalysis at the surface of both glassy carbon and Hg-pool electrodes. The conformation of the macrocyclic ligand determines the dimensionality and shape of the catalytically active species generated on the electrode.

Here we report on the examination of 12 guests (G1–12) interactions with the aggregates of tetramethylensulfonated tetrapentylcalix[4]resorcinarene ( H ) and the azo-pH-indicator methyl orange (MO). At pH 4.2, addition of 40 and 100 equiv. of the guests to 40:1 H :MO solution resulted in deprotonation of the dye accompanied by UV/Vis spectra changes. Variation of MO deprotonation degree in the presence of G1–12 is discussed in relation to the guest interactions with the aggregated H and competition with the surface-bound MO.

Silver nanoparticles in the bulk solution were obtained by the potentiostatic electrolysis in undivided cell using silver anode at the potential of the mediator reduction (tetraviologen calix[4]resorcine) at room temperature in DMF/0.1 M Bu4NPF6 media. The metal nanoparticles aggregate to form larger particles eventually. Keywords: Electrochemical synthesis, Ag0 nanoparticle, Mediator, Tetraviologen calix[4]resorcine

The present work introduces the easy modification of the water-in-oil microemulsion procedure aimed at the doping of the Tb(III) complexes within core or shell zones of the silica nanoparticles (SNs), which are designated as "core-shell", "shell", and "core". The dye molecules, chelating ligands, and copper ions were applied as the quenchers of Tb(III)-centered luminescence through dynamic or/and static mechanisms. The binding of the quenchers at the silica/water interface results in the quenching of the Tb(III) complexes within SNs, which, in turn, is greatly dependent on the synthetic procedure. The luminescence of "core" SNs remains unchanged under the binding of the quenchers at the silica/water interface. The quenching through dynamic mechanism is more significant for "core-shell" and "shell" than for "core" SNs. Thus, both "core-shell" and "shell" SNs have enough percentage of the Tb(III) complexes located close to the interface for efficient quenching through the energy transfer. The quenching through the ion or ligand exchange is most efficient for "core-shell" SNs due to the greatest percentage of the Tb(III) complexes at the silica/water interface, which correlates with the used synthetic procedure. The highlighted regularities introduce the applicability of "core-shell" SNs used as silica beads for phosphatidylcholine bilayers in sensing their permeability toward the quenching ions.

The electro-optic coefficients of 20, 33 and 21 pm V –1 for branched methacrylic copolymers FI, FII and FIII, respectively, with different chromophore contents were determined by a Teng–Man ellipsometric technique.

Fuel cell (FC) test results have been obtained for the first time with the bis-ligand nickel(ii) complex of 1,4-diaza-3,7-diphosphacyclootane heterogeneous catalyst. Using AFM technique the [Ni(PPh...

The present work introduces composite luminescent nanoparticles (Ag

The present work introduces for the first time a nanoparticulate approach for ex vivo monitoring of acetylcholinesterase-catalyzed hydrolysis of endogenous acetylcholine released from nerve varicosities in mice atria. Amino-modified 20-nm size silica nanoparticles (SNs) doped by luminescent Tb(III) complexes were applied as the nanosensors. Their sensing capacity results from the decreased intensity of Tb(III)-centred luminescence due to the quenching effect of acetic acid derived from acetylcholinesterase-catalyzed hydrolysis of acetylcholine. Sensitivity of the SNs in monitoring acetylcholine hydrolysis was confirmed by in vitro experiments. Isolated atria were exposed to the nanosensors for 10 min to stain cell membranes. Acetylcholine hydrolysis was monitored optically in the atria samples by measuring quenching of Tb(III)-centred luminescence by acetic acid derived from endogenous acetylcholine due to its acetylcholinesterase-catalyzed hydrolysis. The reliability of the sensing was demonstrated by the quenching effect of exogenous acetylcholine added to the bath solution. Additionally, no luminescence quenching occurred when the atria were pre-treated with the acetylcholinesterase inhibitor paraoxon.

Polyelectrolyte-coated nanoparticles consisting of terbium and gadolinium complexes with calix[ 4] arene tetra-diketone ligand were first synthesized. The antenna effect of the ligand on Tb(III) green luminescence and the presence of water molecules in the coordination sphere of Gd(III) bring strong luminescent and magnetic performance to the core-shell nanoparticles. The size and the core-shell morphology of the colloids were studied using transmission electron microscopy and dynamic light scattering. The correlation between photophysical and magnetic properties of the nanoparticles and their core composition was highlighted. The core composition was optimized for the longitudinal relaxivity to be greater than that of the commercial magnetic resonance imaging (MRI) contrast agents together with high level of Tb(III)-centered luminescence. The tuning of both magnetic and luminescent output of nanoparticles is obtained via the simple variation of lanthanide chelates concentrations in the initial synthetic solution. The exposure of the pheochromocytoma 12 (PC 12) tumor cells and periphery human blood lymphocytes to nanoparticles results in negligible effect on cell viability, decreased platelet aggregation and bright coloring, indicating the nanoparticles as promising candidates for dual magneto-fluorescent bioimaging. Funding Agencies|Swedish Institute scholarship; President of Russian Federation [MK-4456.2015.3]; Russian Government Program of Competitive Growth of Kazan Federal University; Swedish Research Council [621-2011-4395]; Royal Academy of Sciences [FOA12 V-111]; Kempe Foundation; Swedish Foundations Consolidator Fellowship; LTU Labbfonden Program

Premicellar aggregation processes were investigated in a wide range of concentrations and temperatures of cetyltrimethylammonium bromide (CTAB) aqueous solutions. Two independent techniques were involved to study adsorption and aggregation of CTAB molecules at the glass/solution interface. Electronic spin resonance (ESR) was used to estimate microviscosity properties through the reorientation correlation time τc of (2,2,6,6-tetramethylpiperidin-1-oxyl), while atomic force microscopy (AFM) was involved to evaluate the CTAB molecule morphology at the glass/solution interface. In the dependence of τc vs the CTAB concentration three discontinuities were revealed within 0.2–0.5, 0.5–1.02, and 1.02–1.1 mM narrow concentration ranges, which are probably connected with the formation of bilayer and hemispherical, hemicylindrical, cylindrical, and spherical admicelles. The images of some of them at the glass surface have been independently obtained by AFM. One-dimensional thin layer (2 nm) of Pt parallel strips on ...

Pectinic polysaccharides were isolated and characterized for the first time from the aerial part of Amaranthus cruentus L. The structural and chemical characteristics of the pectinic polysaccharides were analyzed by NMR, IR, HPLC, and AFM. It was shown that amaranth pectin had a linear α-1,4-D-galacturonan portion and branched rhamnogalacturonan regions. The neutral sugars were Rha, Ara, Gal, and Xyl.

The article introduces transverse relaxation rates of water protons in the aqueous hydrophilic colloids synthesized on the basis of the oleate-coated iron oxide nanoparticles (17 nm) with non-ionic and cationic surfactants, triblock copolymers, polyethyleneimine (PEI) and 4,5-dihydroxybenzene-1,3-disulfoacid disodium salt (Tiron) as hydrophilic components. The IR spectroscopy, atomic force and transmission electron microscopy, along with dynamic light scattering data were obtained to evaluate the content of the hydrophilic coating, the clustering of iron oxide nanoparticles within the hydrophilic covering and the aggregation of hydrophilic nanoclusters. The analysis of the obtained results together with transverse relaxation rates under various concentration, counter-ion and temperature conditions reveals the particular importance of the water molecules diffusion in the outer hydrophilic layer versus the nearest to the iron oxide core layer. The obtained results reveal the counter ion binding with the charged hydrophilic iron oxide colloids as a route to affect the water transverse relaxation rates by biorelevant anionic substrates such as adenosine triphosphates.

The work presents the synthesis of a novel calix[4]resorcinarene cavitand bearing four 1,3-diketone groups at the upper rim and its complex formation with Tb(III) ions in DMF and DMSO solutions. Electrospray ionization mass spectra, 1H NMR, UV-Vis and luminescence spectra indicate a long (three hours at least) equilibration time for the complex formation between the cavitand and Tb(III) in alkaline DMF and DMSO solutions. These results are explained by the restricted keto–enol conversion, resulting from the steric hindrance effect of the methylenedioxy-groups linking the benzene rings within the cavitand framework. A facile synthetic route to convert luminescent Tb(III) complexes of various stoichiometries into luminescent hydrophilic colloids is disclosed in this work. The route is based on the reprecipitation of the Tb(III) complexes from DMF to aqueous solutions with further polyelectrolyte deposition without prior separation of the luminescent complexes. The luminescent colloids exhibit high stability over time and in buffer systems, which is a prerequisite for their applicability in analysis and biolabeling.

Two variants of layer-by-layer deposition of polyelectrolytes (polyacrylic acid and polyethyleneimine) for the encapsulation of low-molecular-weight hydrophobic substrates (carboxylic acid esters) were proposed. The spectrophotometric method was used to study the kinetics of alkaline hydrolysis of the esters by monitoring the permeability of microcapsule shells. The first procedure provides a preliminary microencapsulation of substrates into the carbonate matrix to form stable capsules 7–10 μm in size with a low wall permeability. According to the second procedure, the polyelectrolytes were adsorbed directly on the dispersed substrate. In this case, nanosized capsules are formed, whose permeability is controlled by the ultrasonic treatment and the number of deposited layers.