Ferucarbotran-loaded red blood cells as long circulating MRI contrast agents: first in vivo results in mice.

Aim: The encapsulation of superparamagnetic iron oxide contrast agents in red blood cells (RBCs) could overcome their rapid removal by reticulo-endothelial system improving their stability in blood circulation.

Materials & Methods: Murine ferucarbotran-loaded RBCs were tested in vivo as new contrasting agents in MRI application.

Results: A superior visualization of organs and cerebral vessels was evidenced in ferucarbotran-loaded RBCs-treated mice compared with the controls.

Interactions of Nitroxide-Conjugated and Non-Conjugated Glycodendrimers with Normal and Cancer Cells and Biocompatibility Studies.

Poly(propyleneimine) glycodendrimers fully modified with maltose units were administered to different cancer cell lines and their effect on cell viability was evaluated by using MTS assay and flow cytometry. The mechanism of dendrimer-cell interactions was investigated by the electron paramagnetic resonance (EPR) technique by using a new nitroxide-conjugated glycodendrimer. The nitroxide groups did not modify both the biological properties (cell viability and apoptosis degree) of the dendrimers in the presence of the cells and the dendrimer-cell interactions.

Characterization of ferucarbotran-loaded RBCs as long circulating magnetic contrast agents.

Aim: The biomedical application of contrast agents based on superparamagnetic iron oxide nanoparticles is still limited because of their short intravascular half-life. The potential of red blood cells (RBCs) loaded with new ferucarbotran nanoparticles as magnetic contrast agents with longer blood retention time has been investigated.

Materials & Methods: Ferucarbotran was loaded into RBCs by a procedure of hypotonic dialysis and isotonic resealing.

Programmable 3D silk bone marrow niche for platelet generation ex vivo and modeling of megakaryopoiesis pathologies.

We present a programmable bioengineered 3-dimensional silk-based bone marrow niche tissue system that successfully mimics the physiology of human bone marrow environment allowing us to manufacture functional human platelets ex vivo. Using stem/progenitor cells, megakaryocyte function and platelet generation were recorded in response to variations in extracellular matrix components, surface topography, stiffness, coculture with endothelial cells, and shear forces. Millions of human platelets were produced and showed to be functional based on multiple activation tests.

USPIO-loaded red blood cells as a biomimetic MR contrast agent: a relaxometric study.

Red blood cells (RBCs) loaded with iron oxide nanoparticles have been proposed as biomimetic constructs with long half-life (ca. 20 days) in the blood compartment and potentially interesting properties (such as relaxivity) as intravascular contrast agents for magnetic resonance imaging. However, the encapsulation of nanoparticles into RBCs might affect their magnetic properties and relaxivity, which may be significantly different from the native suspension.

New strategies to prolong the in vivo life span of iron-based contrast agents for MRI.

Superparamagnetic iron oxide (SPIO) and ultra small superparamagnetic iron oxide (USPIO) nanoparticles have been developed as magnetic resonance imaging (MRI) contrast agents. Iron oxide nanoparticles, that become superparamagnetic if the core particle diameter is ~ 30 nm or less, present R1 and R2 relaxivities which are much higher than those of conventional paramagnetic gadolinium chelates. Generally, these magnetic particles are coated with biocompatible polymers that prevent the agglomeration of the colloidal suspension and improve their blood distribution profile.

Red blood cells as carriers in magnetic particle imaging.

Red blood cells (RBCs) represent intravascular carriers for drugs, biologics, and other therapeutic agents, characterized by their unique longevity in the bloodstream, availability, considerable surface and volume, high biocompatibility, and natural mechanisms for safe elimination. Recently, the potential of RBCs loaded with superparamagnetic iron oxide (SPIO) nanoparticles as a tracer material for magnetic particle imaging (MPI) to realize a blood-pool tracer agent with longer blood retention time for imaging of the circulatory system, has been investigated. MPI is a new tomographic imaging approach that can quantitatively map magnetic nanoparticle distributions in vivo.

Dexamethasone restrains ongoing expression of interleukin-23p19 in peripheral blood-derived human macrophages.

Background: Since its recent discovery, interleukin-23 has been shown to be involved in the pathogenesis of autoimmune diseases favoring the development of a T cell subset referred to as T helper 17. Glucocorticoids are widely employed in inflammatory and autoimmune diseases as they inhibit pro-inflammatory signaling and prevent production of inflammation mediators. Very limited information is available about the efficacy of synthetic glucocorticoids in containing the expression of interleukin-23 under cell activation.

Encapsulation of superparamagnetic nanoparticles into red blood cells as new carriers of MRI contrast agents.

Aims: The half-life of superparamagnetic iron oxide nanoparticles in the bloodstream is very short since they are rapidly taken up by the reticuloendothelial system. In this article, we report the encapsulation of different magnetic nanoparticles into human erythrocytes to increase their blood circulation time.

Materials & Methods: Newly synthesized and commercially available nanoparticles were evaluated for the encapsulation into red blood cells through the transient opening of membrane pores by controlled hypotonic dialysis and successive isotonic resealing and reannealing of cells.

Effect of the redox state on HIV-1 tat protein multimerization and cell internalization and trafficking.

The redox state of the cysteine-rich region of the HIV Tat protein is known to play a crucial role in Tat biological activity. In this article, we show that Tat displays two alternative functional states depending on the presence of either one or three reduced sulphydryl groups in the cysteine-rich region, respectively. Using different approaches, a disulfide pattern has been defined for the Tat protein and a specific DTT-dependent breaking order of disulfide bonds highlighted.

New biomimetic constructs for improved in vivo circulation of superparamagnetic nanoparticles.

Superparamagnetic iron oxide nanoparticles (SPIOs) have been produced and used as a potent and versatile contrast media for magnetic resonance imaging (MRI). Despite a number of efforts to improve their surface chemistry and biocompatibility, the SPIOs half life in blood circulation is very short and they are rapidly taken up by the reticuloendothelial system (RES). In this paper we describe a new method that permits to avoid the rapid clearance of SPIOs.