Optimized microwave-assisted functionalization and quantification of superficial amino groups on porous silicon nanostructured microparticles.

This work presents an optimized microwave (MW)-assisted method for the chemical functionalization of porous silicon particles (PSip). 3-(Aminopropyl)triethoxysilane (APTES) was grafted on previously stabilized PSip. The functionalization efficiency was studied and optimized in terms of reaction time (Rt) and reaction temperature (RT) using a central composite design (CCD).

Non-Covalently Pre-Assembled High-Performance Near-Infrared Fluorescent Molecular Probes for Cancer Imaging.

New fluorescent molecular probes, which can selectively target specific cell surface receptors, are needed for microscopy, in vivo imaging, and image guided surgery. The preparation of multivalent probes using standard synthetic chemistry can be a laborious process due to low reaction yields caused by steric effects. In this study, fluorescent molecular probes were prepared by a programmed non-covalent pre-assembly process that used a near-infrared fluorescent squaraine dye to thread a macrocycle bearing a cyclic arginine-glycine-aspartate peptide antagonist (cRGDfK) as a cancer targeting unit.

Structural Control of Kinetics for Macrocycle Threading by Fluorescent Squaraine Dye in Water.

While the general concept of steric speed bumps has been demonstrated in rotaxane shuttles and macrocycle threading systems, the sensitivity of speed bump effects has not been evaluated as a function of structural geometry. Values of K and k for macrocycle threading in water are reported for a series of homologous squaraine dyes with different substituents (speed bumps) on the flanking chains and two macrocycles with different cavity sizes. Sensitivity to a steric speed bump effect was found to depend on (a) structural location, being lowest when the speed bump was near the end of a flanking chain, and (b) macrocycle cavity size, which was enhanced when the cavity was constricted.

Non-Covalent Assembly Method that Simultaneously Endows a Liposome Surface with Targeting Ligands, Protective PEG Chains, and Deep-Red Fluorescence Reporter Groups.

A new self-assembly method is used to rapidly functionalize the surface of liposomes without perturbing the membrane integrity or causing leakage of the aqueous contents. The key molecule is a cholesterol-squaraine-PEG conjugate with three important structural elements: a cholesterol membrane anchor, a fluorescent squaraine docking station that allows rapid and high-affinity macrocycle threading, and a long PEG-2000 chain to provide steric shielding of the decorated liposome. The two-step method involves spontaneous insertion of the conjugate into the outer leaflet of pre-formed liposomes followed by squaraine threading with a tetralactam macrocycle that has appended targeting ligands.

Antiplasmodial activity of targeted zinc(II)-dipicolylamine complexes.

This study measured the antiplasmodial activity of nine zinc-dipicolylamine (ZnDPA) complexes against three strains of Plasmodium falciparum, the causative parasite of malaria. Growth inhibition assays showed significant activity against all tested strains, with 50% inhibitory concentrations between 5 and 600nM and almost no toxic effect against host cells including healthy red blood cells. Fluorescence microscopy studies with a green-fluorescent ZnDPA probe showed selective targeting of infected red blood cells.

5,11-Diisopropyl-2,8-dimethyl-1H,7H-diimidazo[c,h][1,6]diazecine dihydrate.

Crystals of the title compound, C(18)H(30)N(6)·2H(2)O, are composed of units of diimidazo[c,h][1,6]diazecine and two water mol-ecules. The asymmetric unit contains one half-molecule of diazecine and one uncoordinated water molecule in a general position. The complete ten-membered heterocycle is generated by an inversion center.