Enhanced assembly stability for amine-based cationic glycolipid.

Glycolipids incorporating positive charges, mediated by an imidazolium cation, have shown potential for effective formulation of vesicular drug carriers, reflecting repulsive electrostatic forces, promoting the formation of nanosized assemblies and preventing unwanted Oswald ripening (Goh et al. (2019), ACS Omega 4, 17,039). Our continuous development of an assembly-based drug delivery system prompted us to investigate a pH-sensitive analogue, leading to the synthesis of a 6-amino-Guerbet glycoside.

Cation-stimulated drug delivery via lipid assembly comprising macrocyclized disaccharides - A DFT study.

In the attempt to create a delivery system for an alkali-cation stimulated drug release, a computational study was conducted, aiming for the evaluation of synthetic access towards glycolipid crown ethers analogs and their potential for coordination-induced changes of packing constraints for molecular assemblies. The results disfavor amide-linkages for the creation of macrocycles around the inter-glycosidic bond of a disaccharide. Conformational changes upon cation coordination of the macrocycle decrease the intersection area for easily accessible macrocycles based on lactose.

Sugar based cationic magnetic core-shell silica nanoparticles for nucleic acid extraction.

Nucleic acid (NA) extraction is an essential step in molecular testing for a wide range of applications. Conventional extraction protocols usually suffer from time consuming removal of non-nucleic acid impurities. In this study, a new magnetic nanoparticle (MNP) is presented to simplify the NA extraction.

Ionic magnetic core-shell nanoparticles for DNA extraction.

Magnetic nanoparticles with specific surface features are interesting materials for biomedical applications. The combination of molecular interactions on small particles with macroscopic cohesion forces offers unique opportunities. This work reports the synthesis of magnetic core-shell nanoparticles with alkylimidazolium coated surface for effective DNA extraction.

Unexpected Reactions of Terminal Alkynes in Targeted "Click Chemistry'' Coppercatalyzed Azide-alkyne Cycloadditions.

Background: High efficiency in terms of reaction yield and purity has led to the extensive utilization of copper-catalyzed azide-alkyne cycloaddition (CuAAC) in various fields of chemistry. Its compatibility with low molecular weight alcohols promotes the application in surfactant synthesis to tackle the miscibility constraints of the reactants.

Objective: For the tuning of surfactant properties, double click coupling of the antipode precursors was attempted.

Imidazolium-Linked Azido-Functionalized Guerbet Glycosides: Multifunctional Surfactants for Biofunctionalization of Vesicles.

Aiming for glycolipid-based vesicles for targeted drug delivery, cationic Guerbet glycosides with spacered click functionality were designed and synthesized. The cationic charge promoted the distribution of the glycolipids during the formulation, thereby leading to homogeneously small vesicles. The positive surface charge of the vesicles stabilizes them against unwanted fusion and promotes interactions of the drug carriers with typical negative charge-dominated target cells.

Synthesis and biological study of acridine-based imidazolium salts.

A new series of acridine based imidazolium salts was synthesized and evaluated for cytotoxicity against human cancer cell lines by an MTT assay. The synthesis applied a coupling of imidazoles with 9-chloroacridines, which originated from an Ullmann condensation of a 2-chloro-benzoic acid with an aniline. The target compounds were obtained in high yields.

Functionalized glycolipids for potential bioconjugation of vesicles.

Two azide-terminated oligoethylene oxide spacered glycolipids have been synthesized, and their assembly behavior has been studied in comparison to the corresponding base surfactants. The results suggest potential of the Guerbet lactoside-based compound for targeted drug delivery, while a coiling of the ethylene oxide linker disfavors the application of the glucoside.

Renewable resources-based approach to biantennary glycolipids.

A new synthesis approach towards biantennary lipids of Guerbet glycoside type was developed based on oleic acid as sustainable resource. Functionalization of the double bond provided access to primary alcohols with α-branched C-skeleton. Formulation studies with corresponding lactosides indicated formation of vesicles with high assembly stability.

Conjugated Oligo-Aromatic Compounds Bearing a 3,4,5-Trimethoxy Moiety: Investigation of Their Antioxidant Activity Correlated with a DFT Study.

A series of heterocyclic compounds bearing the well-known free radical scavenging 3,4,5-trimethoxybenzyloxy group, was synthesized. The key compound 4-(3,4,5-trimethoxybenzyl-oxy)benzohydrazide was converted into thiosemicarbazide derivatives, which were subsequently cyclized with NaOH to provide 1,2,4-triazole derivatives. Alternative treatment of the acid hydrazide with carbon disulfide in the presence of KOH led to the corresponding 1,3,4-oxadiazole and various alkylated derivatives.

Correlation of antioxidant activities with theoretical studies for new hydrazone compounds bearing a 3,4,5-trimethoxy benzyl moiety.

A new series of antioxidants, namely imines bearing the well-known free radical scavenger group 3,4,5-trimethoxybenzyloxy, was designed and synthesized. Theoretical calculations based on density functional theory (DFT) were performed to understand the antioxidant activities. Experimental studies evaluating the antioxidant activities of the compounds using DPPH and FRAP assays verified the predictions obtained by DMOL3 based on DFT.

Alkyl-imidazolium glycosides: non-ionic-cationic hybrid surfactants from renewable resources.

A series of surfactants combining carbohydrate and imidazolium head groups were prepared and investigated on their assembly behavior. The presence of the imidazolium group dominated the interactions of the surfactants, leading to high CMCs and large molecular surface areas, reflected in curved rather than lamellar surfactant assemblies. The carbohydrate, on the other hand, stabilized molecular assemblies slightly and reduced the surface tension of surfactant solutions considerably.

Functional glycolipid-crown-ethers by click chemistry.

A series of glycolipid crown ether analogs was prepared by bis-propargylation of lauryl glycoside followed by subsequent click-coupling with ethylene glycol-based diazides. The triazole-linked macrocycles were obtained in remarkable high yields. While the surfactant assembly was affected by presence of sodium ions, suggesting the formation of complexes, no ion-selectivity was observed for the macrocylic ligands.

New Y-shaped surfactants from renewable resources.

A series of sugar-based surfactants, involving a single hydrophobic chain (C12) and two side-by-side arranged head groups, was prepared form simple glucose precursors. All surfactants were highly water soluble and exhibited exclusively micellar assemblies. This behavior makes them interesting candidates for oil in water emulsifiers.

Deuterium NMR Investigation of the lyotropic phases of alkyl β-glycoside/D2O systems.

We have investigated the phase behavior of four glycosides (βC8OGlc, βC8SGlc, βC10OGlc, βC8OGal) in water and D2O by optical polarizing microscopy and deuterium NMR. Previously published phase diagrams were evaluated by deuterium NMR, via monitoring D2O spectra, and confirmed the presence of the hexagonal, bicontinuous cubic, and lamellar phases in these glycosides. We have also shown the presence of the gel phase in (βC10OGlc) and observed the extensive supercooling of the lamellar phase to temperatures well below the Kraft line.

N-linked glycolipids by Staudinger coupling of glycosylated alkyl diazides with fatty acids.

Aiming for new glycolipids with enhanced chemical stability and close structural similarity to natural cell membrane lipids for the development of a drug delivery system, we have synthesized double amide analogs of glyco-glycerolipids. The synthesis applied a Staudinger reaction based coupling of a 1,3-diazide with fatty acid chlorides. While the concept furnished the desired glucosides in reasonable yields, the corresponding lactosides formed a tetrahydropyrimidine based 1:1 coupling product instead.

Effect of vesicle's membrane packing behaviour on skin penetration of model lipophilic drug.

Disaccharide glycosides synthesised from food grade resources consist of the hydrophilic head group of maltose or lactose and provide better hydrophilic-lipophilic balance (HLB = 12) to the long alkyl chain derived from palm oil (PO) and palm kernel oil (PKO). Maltoside provides more flexibility in the vesicle's membrane because of its low packing density in the bilayer membrane compared to lactoside. The bending of the molecular structure in maltose form a less compact assembly for maltoside, whereas lactose is more linear in shape.

Biosynthesis and characterization of polyhydroxyalkanoates copolymers produced by Pseudomonas putida Bet001 isolated from palm oil mill effluent.

The biosynthesis and characterization of medium chain length poly-3-hydroxyalkanoates (mcl-PHA) produced by Pseudomonas putida Bet001 isolated from palm oil mill effluent was studied. The biosynthesis of mcl-PHA in this newly isolated microorganism follows a growth-associated trend. Mcl-PHA accumulation ranging from 49.

Molecular dynamics study of anhydrous lamellar structures of synthetic glycolipids: effects of chain branching and disaccharide headgroup.

Glycolipids form materials of considerable potential for a wide range of surfactant and thin film applications. Understanding the effect of glycolipid covalent structure on the properties of their thermotropic and lyotropic assemblies is a key step toward rational design of new glycolipid-based materials. Here, we perform molecular dynamics simulations of anhydrous bilayers of dodecyl β-maltoside, dodecyl β-cellobioside, dodecyl β-isomaltoside, and a C(12)C(10) branched β-maltoside.

Alkyl triazole glycosides (ATGs)--a new class of bio-related surfactants.

A series of glucose based surfactants varying in chain length and anomeric configuration were synthesized and investigated on their surfactant properties. The synthesis applied glycosylation of propargyl alcohol followed by cycloaddition with alkyl azides in CLICK chemistry fashion. This approach enables a homogeneous coupling of hydrophilic unprotected sugars and hydrophobic paraffin components in low molecular weight alcohols without solvent side reactions, as commonly found for APGs.

Fluorescence probing of the temperature-induced phase transition in a glycolipid self-assembly: hexagonal ↔ micellar and cubic ↔ lamellar.

Water-driven self-assembly of lipids displays a variety of liquid crystalline phases that are crucial for membrane functions. Herein, we characterize the temperature-induced phase transitions in two compositions of an aqueous self-assembly system of the octyl β-D-glucoside (βGlcOC(8)) system, using steady-state and time-resolved fluorescence measurements. The phase transitions hexagonal ↔ micellar and cubic ↔ lamellar were investigated using tryptophan (Trp) and two of its ester derivatives (Trp-C(4) and Trp-C(8)) to probe the polar headgroup region and pyrene to probe the hydrophobic tail region.

4-Formyl-phenyl 2,3,4,6-tetra-O-acetyl-β-d-galactopyran-oside.

The galactose ring in the title compound, C(21)H(24)O(11), has a chair conformation with the substituted benzene ring occupying an equatorial position. The crystal packing features C-H⋯O inter-actions that lead to the formation of supra-molecular layers in the ab plane.

4-Formyl-phenyl 2,3,4,6-tetra-O-acetyl-β-d-glucopyran-oside.

The pyran-oside ring in the title compound, C(21)H(24)O(11), has a chair conformation with the substituted benzene ring occupying an equatorial position. The crystal packing is dominated by C-H⋯O inter-actions that lead to the formation of supra-molecular layers in the ab plane.