A novel supramolecular catalytic system based on amphiphilic triphenylphosphonium bromide for the hydrolysis of phosphorus acid esters

© 2015 Elsevier B.V. The biomimetic nature of micellar catalysis can significantly affect the rate of chemical reactions due to the effects of concentration and the change of microenvironment. Here, a key role is played by the nature of the head group. The catalytic activity of alkyltriphenylphosphonium bromides (TPPB-n; n= 10, 12, 14, 16, 18; n is the number of carbon atoms in alkyl groups) in the nucleophilic substitution of p-nitrophenyl esters of alkylchloromethylphosphonic acid were investigated by the method of spectrophotometry. Using pyrene, prodan and Sudan I as probes the values of critical micelle concentrations and aggregation numbers were determined. A comparison of the results of kinetic dependence processing by Berezin equation obtained for TPPB series with the known ammonium analogues was carried out. It was found that for TPPB- n series, the higher acceleration of reaction has been achieved due to concentration factor compared to ammonium surfactants. This agrees with the fact that alkyltriphenylphosphonium bromides demonstrate higher aggregation activity forming micelles with higher solubilizing capacity

The polyacrylic acid/modified chitosan capsules with tunable release of small hydrophobic probe and drug

© 2015 Elsevier B.V. Nanocapsules (≤200. nm) with a protection effect toward small hydrophobic guests (p-nitrophenyl laurate and acetylsalicylic acid, aspirin) and a tunable sustained release behavior have been fabricated through the layer-by-layer deposition of polyacrylic acid and modified chitosan. Cationic surfactant, cetyltrimethylammonium bromide, was used to increase the affinity of polyelectrolyte to the substrate. The release profile was monitored through original protocol involving a fast cleavage of the substrate released and a spectrophotometric control of the product. The shell permeability of the capsules and hence their protective effect may be tuned through the variation of the number of layers deposited, the sonication, and the adjustment of solution pH. Importantly, the dispersed loads serving as a template for the capsule fabrication may control their properties, including shell permeability

Fast computation of latent correlations.

Latent Gaussian copula models provide a powerful means to perform multi-view data integration since these models can seamlessly express dependencies between mixed variable types (binary, continuous, zero-inflated) via latent Gaussian correlations. The estimation of these latent correlations, however, comes at considerable computational cost, having prevented the routine use of these models on high-dimensional data. Here, we propose a new computational approach for estimating latent correlations via a hybrid multilinear interpolation and optimization scheme. Our approach speeds up the current state of the art computation by several orders of magnitude, thus allowing fast computation of latent Gaussian copula models even when the number of variables p is large. We provide theoretical guarantees for the approximation error of our numerical scheme and support its excellent performance on simulated and real-world data. We illustrate the practical advantages of our method on high-dimensional sparse quantitative and relative abundance microbiome data as well as multi-view data from The Cancer Genome Atlas Project. Our method is implemented in the R package mixedCCA, available at https://github.com/irinagain/mixedCCA

A novel supramolecular catalytic system based on amphiphilic triphenylphosphonium bromide for the hydrolysis of phosphorus acid esters

© 2015 Elsevier B.V. The biomimetic nature of micellar catalysis can significantly affect the rate of chemical reactions due to the effects of concentration and the change of microenvironment. Here, a key role is played by the nature of the head group. The catalytic activity of alkyltriphenylphosphonium bromides (TPPB-n; n= 10, 12, 14, 16, 18; n is the number of carbon atoms in alkyl groups) in the nucleophilic substitution of p-nitrophenyl esters of alkylchloromethylphosphonic acid were investigated by the method of spectrophotometry. Using pyrene, prodan and Sudan I as probes the values of critical micelle concentrations and aggregation numbers were determined. A comparison of the results of kinetic dependence processing by Berezin equation obtained for TPPB series with the known ammonium analogues was carried out. It was found that for TPPB- n series, the higher acceleration of reaction has been achieved due to concentration factor compared to ammonium surfactants. This agrees with the fact that alkyltriphenylphosphonium bromides demonstrate higher aggregation activity forming micelles with higher solubilizing capacity

A novel supramolecular catalytic system based on amphiphilic triphenylphosphonium bromide for the hydrolysis of phosphorus acid esters

© 2015 Elsevier B.V. The biomimetic nature of micellar catalysis can significantly affect the rate of chemical reactions due to the effects of concentration and the change of microenvironment. Here, a key role is played by the nature of the head group. The catalytic activity of alkyltriphenylphosphonium bromides (TPPB-n; n= 10, 12, 14, 16, 18; n is the number of carbon atoms in alkyl groups) in the nucleophilic substitution of p-nitrophenyl esters of alkylchloromethylphosphonic acid were investigated by the method of spectrophotometry. Using pyrene, prodan and Sudan I as probes the values of critical micelle concentrations and aggregation numbers were determined. A comparison of the results of kinetic dependence processing by Berezin equation obtained for TPPB series with the known ammonium analogues was carried out. It was found that for TPPB- n series, the higher acceleration of reaction has been achieved due to concentration factor compared to ammonium surfactants. This agrees with the fact that alkyltriphenylphosphonium bromides demonstrate higher aggregation activity forming micelles with higher solubilizing capacity

A novel supramolecular catalytic system based on amphiphilic triphenylphosphonium bromide for the hydrolysis of phosphorus acid esters

© 2015 Elsevier B.V. The biomimetic nature of micellar catalysis can significantly affect the rate of chemical reactions due to the effects of concentration and the change of microenvironment. Here, a key role is played by the nature of the head group. The catalytic activity of alkyltriphenylphosphonium bromides (TPPB-n; n= 10, 12, 14, 16, 18; n is the number of carbon atoms in alkyl groups) in the nucleophilic substitution of p-nitrophenyl esters of alkylchloromethylphosphonic acid were investigated by the method of spectrophotometry. Using pyrene, prodan and Sudan I as probes the values of critical micelle concentrations and aggregation numbers were determined. A comparison of the results of kinetic dependence processing by Berezin equation obtained for TPPB series with the known ammonium analogues was carried out. It was found that for TPPB- n series, the higher acceleration of reaction has been achieved due to concentration factor compared to ammonium surfactants. This agrees with the fact that alkyltriphenylphosphonium bromides demonstrate higher aggregation activity forming micelles with higher solubilizing capacity

The polyacrylic acid/modified chitosan capsules with tunable release of small hydrophobic probe and drug

© 2015 Elsevier B.V. Nanocapsules (≤200. nm) with a protection effect toward small hydrophobic guests (p-nitrophenyl laurate and acetylsalicylic acid, aspirin) and a tunable sustained release behavior have been fabricated through the layer-by-layer deposition of polyacrylic acid and modified chitosan. Cationic surfactant, cetyltrimethylammonium bromide, was used to increase the affinity of polyelectrolyte to the substrate. The release profile was monitored through original protocol involving a fast cleavage of the substrate released and a spectrophotometric control of the product. The shell permeability of the capsules and hence their protective effect may be tuned through the variation of the number of layers deposited, the sonication, and the adjustment of solution pH. Importantly, the dispersed loads serving as a template for the capsule fabrication may control their properties, including shell permeability

The polyacrylic acid/modified chitosan capsules with tunable release of small hydrophobic probe and drug

© 2015 Elsevier B.V. Nanocapsules (≤200. nm) with a protection effect toward small hydrophobic guests (p-nitrophenyl laurate and acetylsalicylic acid, aspirin) and a tunable sustained release behavior have been fabricated through the layer-by-layer deposition of polyacrylic acid and modified chitosan. Cationic surfactant, cetyltrimethylammonium bromide, was used to increase the affinity of polyelectrolyte to the substrate. The release profile was monitored through original protocol involving a fast cleavage of the substrate released and a spectrophotometric control of the product. The shell permeability of the capsules and hence their protective effect may be tuned through the variation of the number of layers deposited, the sonication, and the adjustment of solution pH. Importantly, the dispersed loads serving as a template for the capsule fabrication may control their properties, including shell permeability

The polyacrylic acid/modified chitosan capsules with tunable release of small hydrophobic probe and drug

© 2015 Elsevier B.V. Nanocapsules (≤200. nm) with a protection effect toward small hydrophobic guests (p-nitrophenyl laurate and acetylsalicylic acid, aspirin) and a tunable sustained release behavior have been fabricated through the layer-by-layer deposition of polyacrylic acid and modified chitosan. Cationic surfactant, cetyltrimethylammonium bromide, was used to increase the affinity of polyelectrolyte to the substrate. The release profile was monitored through original protocol involving a fast cleavage of the substrate released and a spectrophotometric control of the product. The shell permeability of the capsules and hence their protective effect may be tuned through the variation of the number of layers deposited, the sonication, and the adjustment of solution pH. Importantly, the dispersed loads serving as a template for the capsule fabrication may control their properties, including shell permeability

Mitochondria-targeted cationic liposomes modified with alkyltriphenylphosphonium bromides loaded with hydrophilic drugs: preparation, cytotoxicity and colocalization assay

© 2019 The Royal Society of Chemistry. The purpose of this work was to obtain cationic liposomes based on 1,2-dipalmitoyl-sn-glycero-3-phosphocholine noncovalently modified using alkyltriphenylphosphonium bromides (TPPB-n) with different lengths of hydrocarbon tail for targeted delivery to mitochondria. The hydrodynamic diameter and electrokinetic potential of hybrid liposomes depending on the lipid/surfactant ratio were monitored in time with the aim to optimize the composition with sufficient stability and positive charge for mitochondria-targeted delivery. It was found that increasing the alkyl tail length of the surfactant (up to TPPB-14) leads to an increase in the positive charge of the liposomes. The most optimal results of stability were obtained for hybrid liposomes based on 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and TPPB-12, TPPB-14. The obtained modified liposomes were loaded with hydrophilic substrates (a model probe Rhodamine B and medicines metronidazole and doxorubicin). This is one of the first examples of fabrication of liposomes noncovalently modified using an amphiphilic TPP cation, with the alkyl tail length of surfactant and TPP/lipid ratio optimized in terms of stability of the liposomes and the binding/release behavior of hydrophilic probes. Using the confocal microscopy method, it was shown that modification of liposomes with a triphenylphosphonium cation results in targeted delivery of encapsulated compounds to mitochondria