Photocatalytic properties of hybrid materials based on a multicharged polymer matrix with encored TiO<inf>2</inf>and noble metal (Pt, Pd or Au) nanoparticles

© The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2020. In this study, we report a synthesis of new nanocomposites, wherein TiO2is introduced into multicharged polymeric matrix and covered with noble metals (Pt, Pd or Au) for the photocatalytic application. A photocatalytic activity investigation was performed by studying the degradation of methylene blue. It revealed that all obtained nanocomposites demonstrate enhanced photocatalytic ability when compared to pure TiO2, under both UV (24 °C) and solar light (−2 °C). The morphology and catalytic properties of the composites depend on the noble metals. The kinetic speed value of photodegradation was found to increase in the following sequence: TiO2< TiO2-NPst ≈ Pd-TiO2@NPSt < Pt-TiO2@NPSt ≈ Au-TiO2@NPSt

Interaction of bovine serum albumin with cationic imidazolium-containing amphiphiles bearing urethane fragment: Effect of hydrophobic tail length

© 2020 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

Photocatalytic properties of supramolecular nanoassociates based on gold and platinum nanoparticles, capped by amphiphilic calix[4]resorcinarenes, towards organic dyes

© 2020 Elsevier B.V. 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

Polymer and supramolecular nanocontainers based on carboxylate derivatives of resorcinarenes for binding of substrates and design of composites for catalysis

© 2020, Springer Science+Business Media LLC. The work describes the synthesis of supramolecular and polymer nanocontainers based on carboxylate resorcinarene derivatives. A comparative analysis of their inclusive characteristics toward hydrophilic and hydrophobic substrates was carried out. The obtained containers and silver nanoparticles were used to develop composite materials, and their catalytic activity in the reduction of {tip}-nitrophenol was examined. It was shown that polymer nanocontainers are more ef cient in binding organic substrates, while the supramolecular containers are more suitable for the design of catalytically active composites. The reduction of {tip}-nitrophenol in the presence of nanocomposites based on supramolecular containers proceeds with a higher rate and does not show an induction period

The construction of supramolecular and hybrid Ag-AgCl nanoparticles with photodynamic therapy action on the base of tetraundecylсalix[4]resorcinarene-mPEG conjugate

The development of new nanomaterials with therapeutic potential is a modern task due to their outstanding properties and promising effectiveness. Here the usage of acylhydrazone bond-based сalix[4]resorcinarene-mPEG conjugate (C11-mPEG) in the formation of both supramolecular and hybrid nanoparticles with in vitro photodynamic therapy (PDT) activity is described. C11-mPEG is hydrolyzed with a decrease in pH of solution; the conjugate and its degradation product have the low hemolytic activity and low cytotoxicity against normal cells. The self-association of the conjugate was studied in the aqueous solutions with pH 7.4 and 5. C11-mPEG forms self-associates that serve as pH-sensitive supramolecular nanocontainers for photosensitizer Methylene Blue (MB). In the in vitro PDT experiment the stronger decrease of tumor cells (M-Hela cells) viability in the presence of encapsulated MB is observed in comparison with free MB. Also C11-mPEG acts as a stabilizing agent for Ag@AgCl nanoparticles, which were obtained with 5/1 and 2/1 Ag+/C11-mPEG molar ratio and different reducing agents (sodium borohydride and hydrazine hydrate). The stronger cytotoxicity of hybrid NPs against tumor cells in comparison with normal was shown. Further it was found that the irradiation of the hybrid nanoparticles at 630 nm leads to the sharp increase in their cytotoxicity against M-Hela cells. The high level of ROS formation in the cells in the presence of both supramolecular and hybrid NPs under in vitro PDT experiment was determined

Doxorubicin delivery by polymer nanocarrier based on N-methylglucamine resorcinarene

© 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group. Herein we describe a simple method for the synthesis of polymer nanocarrier for the doxorubicin delivery. The nanocarrier consists of N-methyl-glucamine resorcinarenes that are covalently bound to phenylboronic acid. The nanocarrier is stable at normal pH but is hydrolysed at pH below 6. It demonstrates low cytotoxicity and haemolytic activity. Doxorubicin was successfully loaded into the nanocarriers cavity and its release occurs at pH. Flow cytometry data showed that the carrier improves the penetration of doxorubicin into M-Hela cancer cell lines. The encapsulated doxorubicin demonstrates higher cytotoxicity towards the cancer cells

Cationic liposomes mediated transdermal delivery of meloxicam and ketoprofen: Optimization of the composition, in vitro and in vivo assessment of efficiency

New liposomes modified with pyrrolidinium surfactants containing a hydroxyethyl fragment (CnPB, n = 12, 14, 16) were prepared for transdermal delivery of non-steroidal anti-inflammatory drugs. In order to obtain the optimal composition, the surfactant/lipid molar ratio (0.02/1; 0.029/1; 0.04/1) and the amphiphile hydrocarbon tail length were varied. Rhodamine B was loaded in all formulations, while meloxicam and ketoprofen in selected ones. For liposomes studied the hydrodynamic diameter was in the range of 80–130 nm, the zeta potential ranged from +35 to +50 mV, EE was 75–99%. Liposome modification leads to a prolonged release of the rhodamine B (up to 10–12 h) and faster release of non-steroidal drugs (up to 7–8 h) in vitro. The ability to cross the skin barrier using Franz cells was investigated for liposomal meloxicam and ketoprofen. The total amount of meloxicam and ketoprofen passed through the Strat-M® membranes during 51 h was 51–114 μg/cm2 and 87–105 μg/cm2 respectively. The evaluation of transdermal diffusion ex vivo showed that total amount of liposomal ketoprofen passed through the skin during 51 h was 140–162 μg/cm2. Liposomes modified with C16PB were found as the most effective inflammation reducing formulation in the carrageenan edema model of rat paw

The pH-responsive calix[4]resorcinarene-mPEG conjugates bearing acylhydrazone bonds: Synthesis and study of the potential as supramolecular drug delivery systems

© 2020 Elsevier B.V. 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

Synthesis of Ag-AgCl nanoparticles capped by calix[4]resorcinarene-mPEG conjugate and their antimicrobial activity

© 2020 Elsevier B.V. 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