Surfactant-free Gd(3+)-ion-containing carbon nanotube MRI contrast agents for stem cell labeling.

There is an ever increasing interest in developing new stem cell therapies. However, imaging and tracking stem cells in vivo after transplantation remains a serious challenge. In this work, we report new, functionalized and high-performance Gd(3+)-ion-containing ultra-short carbon nanotube (US-tube) MRI contrast agent (CA) materials which are highly-water-dispersible (ca.

Gadolinium oxide nanoplates with high longitudinal relaxivity for magnetic resonance imaging.

Molecular-based contrast agents for magnetic resonance imaging (MRI) are often characterized by insufficient relaxivity, thus requiring the systemic injection of high doses to induce sufficient contrast enhancement at the target site. In this work, gadolinium oxide (Gd2O3) nanoplates are produced via a thermal decomposition method. The nanoplates have a core diameter varying from 2 to 22 nm, a thickness of 1 to 2 nm and are coated with either an oleic acid bilayer or an octylamine modified poly(acrylic acid) (PAA-OA) polymer layer.

Geometrical confinement of Gd(DOTA) molecules within mesoporous silicon nanoconstructs for MR imaging of cancer.

Porous silicon has been used for the delivery of therapeutic and imaging agents in several biomedical applications. Here, mesoporous silicon nanoconstructs (SiMPs) with a discoidal shape and a sub-micrometer size (1000×400nm) have been conjugated with gadolinium-tetraazacyclododecane tetraacetic acid Gd(DOTA) molecules and proposed as contrast agents for Magnetic Resonance Imaging. The surface of the SiMPs with different porosities - small pore (SP: ∼5nm) and huge pore (HP: ∼40nm) - and of bulk, non-porous silica beads (1000nm in diameter) have been modified with covalently attached (3-aminopropyl)triethoxysilane (APTES) groups, conjugated with DOTA molecules, and reacted with an aqueous solution of GdCl3.

Enhanced MRI relaxivity of Gd(3+) -based contrast agents geometrically confined within porous nanoconstructs.

Gadolinium chelates, which are currently approved for clinical MRI use, provide relaxivities well below their theoretical limit, and they also lack tissue specificity. Recently, the geometrical confinement of Gd(3+) -based contrast agents (CAs) within porous structures has been proposed as a novel, alternative strategy to improve relaxivity without chemical modification of the CA. Here, we have characterized and optimized the performance of MRI nanoconstructs obtained by loading [Gd(DTPA)(H(2) O)](2-) (Magnevist®) into the pores of injectable mesoporous silicon particles.

Geometrical confinement of gadolinium-based contrast agents in nanoporous particles enhances T1 contrast.

Magnetic resonance imaging contrast agents are currently designed by modifying their structural and physiochemical properties to improve relaxivity and to enhance image contrast. Here, we show a general method for increasing relaxivity by confining contrast agents inside the nanoporous structure of silicon particles. Magnevist, gadofullerenes and gadonanotubes were loaded inside the pores of quasi-hemispherical and discoidal particles.

Lycopene attenuates diabetes-associated cognitive decline in rats.

Diabetes-induced learning and memory impairment, characterized by impaired cognitive functions and neurochemical and structural abnormalities, involve direct neuronal damage caused by intracellular glucose. The present study was designed to investigate the effect of lycopene, a potent anti-oxidant and anti-inflammatory molecule, on cognitive functions, oxidative stress and inflammation in streptozotocin (STZ)-induced diabetic rats. Cognitive functions were investigated using a spatial version of the Morris water maze test.

Nonequilibrium thermodynamics formalism for Marcus theory of heterogeneous and self-exchange electron-transfer rate constants.

The cross-exchange electron-transfer rate constant expression of Marcus is derived from the Flux-force formalism of non-equilibrium thermodynamics. The relationship governing the Onsager's phenomenological coefficients for cross-exchange and self-exchange electron-transfer processes is deduced. Onsager's phenomenological coefficient pertaining to the Butler-Volmer equation is derived and estimated from the experimental exchange current densities.