Click Chemistry for Liposome Surface Modification.

Click chemistry, and particularly azide-alkyne cycloaddition, represents one of the principal bioconjugation strategies that can be used to conveniently attach various ligands to the surface of preformed liposomes. This efficient and chemoselective reaction involves a Cu(I)-catalyzed azide-alkyne cycloaddition which can be performed under mild experimental conditions in aqueous media. Here we describe the application of a model click reaction to the conjugation, in a single step, of unprotected α-1-thiomannosyl ligands, functionalized with an azide group, to liposomes containing a terminal alkyne-functionalized lipid anchor.

Cyclic Anhydrides as Powerful Tools for Bioconjugation and Smart Delivery.

Cyclic anhydrides are potent tools for bioconjugation; therefore, they are broadly used in the functionalization of biomolecules and carriers. The pH-dependent stability and reactivity, as well as the physical properties, can be tuned by the structure of the cyclic anhydride used; thus, their application in smart delivery systems has become very important. This review intends to cover the last updates in the use of cyclic anhydrides as pH-sensitive linkers, their differences in reactivity, and the latest applications found in bioconjugation chemistry or chemical biology, and when possible, in drug delivery.

Molecularly Imprinted Microrods via Mesophase Polymerization.

The aim of the present research work was the synthesis of molecularly imprinted polymers (MIPs) with a rod-like geometry via "mesophase polymerization". The ternary lyotropic system consisting of sodium dodecyl sulfate (SDS), water, and decanol was chosen to prepare a hexagonal mesophase to direct the morphology of the synthesized imprinted polymers using theophylline, methacrylic acid, and ethylene glycol dimethacrylate as a drug model template, a functional monomer, and a crosslinker, respectively. The obtained molecularly imprinted microrods (MIMs) were assessed by performing binding experiments and in vitro release studies, and the obtained results highlighted good selective recognition abilities and sustained release properties.

Solubilization of α-galactosylceramide in aqueous medium: Impact on Natural Killer T cell activation and antitumor responses.

The potent antitumor effect of α-galactosylceramide (α-GalCer) is based on its recognition by invariant Natural Killer T cells (iNKT) after its capture and presentation by antigen presenting cells including dendritic cells (DCs). Synthetic α-GalCer has already been tested in advanced cancer patients but no or only moderate clinical responses were obtained. To optimize α-GalCer efficacy, we have postulated that alternative formulations impacting its molecular organization in aqueous medium could modify DC uptake and iNKT-based immune responses.

Coupling of Ligands to the Liposome Surface by Click Chemistry.

Click chemistry represents a new bioconjugation strategy that can be used to conveniently attach various ligands to the surface of preformed liposomes. This efficient and chemoselective reaction involves a Cu(I)-catalyzed azide-alkyne cycloaddition which can be performed under mild experimental conditions in aqueous media. Here we describe the application of a model click reaction to the conjugation, in a single step, of unprotected α-1-thiomannosyl ligands, functionalized with an azide group, to liposomes containing a terminal alkyne-functionalized lipid anchor.

Synthetic ligands of death receptor 5 display a cell-selective agonistic effect at different oligomerization levels.

DR4 (Death Receptor 4) and DR5 (Death Receptor 5) are two potential targets for cancer therapy due to their ability to trigger apoptosis of cancer cells, but not normal ones, when activated by their cognate ligand TRAIL (TNF related apoptosis-inducing ligand). Therapies based on soluble recombinant TRAIL or agonist antibodies directed against one of the receptors are currently under clinical trials. However, TRAIL-R positive tumor cells are frequently resistant to TRAIL induced apoptosis.

Smart tools and orthogonal click-like reactions onto small unilamellar vesicles: Additional molecular data.

We present here the synthetic routes and the experimental data (NMR and MS spectra) for model reactions for copper-free Huisgen 1,4-cycloaddition, Staudinger ligation and for addition of a dithiol on a dibromomaleimide ring. Starting materials were synthesized from the commercially available 4-chlorophenethylamine, previously described 2-(cyclooct-2-yn-1-yloxy)acetic acid, 1-fluorocyclooct-2-ynecarboxylic acid, commercial 2-(diphenylphosphino)terephthalic acid 1-methyl 4-pentafluorophenyl diester and dibromomaleimide. In all cases, the expected compounds were obtained with good yield (50% to quantitative).

Smart tools and orthogonal click-like reactions onto small unilamellar vesicles.

Click-based reactions were conducted at the surface of small unilamellar vesicles (SUVs) to provide onto-vesicle chemistry with efficient innovative ready-for-use tools. For that purpose, four amphiphilic molecules were designed to insert into bilayers while presenting a reactive functional head. In this manner, a dioleylglycero-ethoxy-ethoxy-ethoxy-ethanamine (DOG-PEG4-NH2) was chosen as a common platform while the reactive amine head was converted into several electrophilic functions.

Novel glycolipid TLR2 ligands of the type Pam2Cys-α-Gal: synthesis and biological properties.

A more complete understanding of the mechanism of action of TLR agonists has fueled the investigation of new synthetic immunoadjuvants. In this context, we designed and synthesized glycolipids of the type Pam(2)Cys-α-Galactose as novel immunoadjuvants. Their synthesis required modifying a hydrophobic tBoc-[2,3-bispalmitoyloxy-(2R)-propyl]-R-cysteinyl moiety, i.

Cationic and anionic lipoplexes inhibit gene transfection by electroporation in vivo.

Background: Nonviral gene therapy still suffers from low efficiency. Methods that would lead to higher gene expression level of longer duration would be a major advance in this field. Lipidic vectors and physical methods have been investigated separately, and both induced gene expression improvement.

Novel powerful water-soluble lipid immunoadjuvants inducing mouse dendritic cell maturation and B cell proliferation using TLR2 pathway.

Four novel water-soluble lipid immunoadjuvants were designed, synthesized and characterized by MS and NMR. They all induce mouse dendritic cell maturation and B cell proliferation. We demonstrate that in spite of the chemical modification, the four compounds remain TLR2 agonists.

Design, synthesis and evaluation of potent thymidylate synthase X inhibitors.

Three synthesized series of compounds based on a thiazolidine core allowed identification of potent inhibitors of thymidylate synthase X. The evaluation of the catalytic activity of the enzyme in the presence of these molecules revealed two distinct classes of compounds that inhibit ThyX with submicromolar concentrations, which could lead, after optimization, to effective inhibitors with potential biomedical interest.

Lipopolythioureas: a new non-cationic system for gene transfer.

A DNA-transfection protocol has been developed that makes use of thiourea non-cationic synthetic lipid, N-[1,3-bis(carbamothioylamino)propan-2-yl]-2-(dialkycarbamoylmethoxy)acetamide. It was found that these new compounds could be formulated without helper lipid and that the N-decanoyl and N-lauryl derivatives transfected B16 cells in the presence of serum with an efficiency at the same level as cationic lipids, under identical conditions. In vivo transfection using intratumoral injection was also investigated.