Encapsulation of new ferucarbotran nanoparticles into red blood cells as potential MPI contrast agent

Abstract

Although a wide range of size and material has been explored to prolong the nanoparticle circulation time, iron-based contrast agents, such as Resovist, have short blood half-life and their application is still limited by macrophages and cells of the reticuloendothelial system (RES) present in the liver and spleen [1]. Encapsulation of superparamagnetic iron oxide (SPIO) nanoparticles into red blood cells (RBCs) has been suggested to increase the blood circulation time of nanoparticles [2]. The RBCs, thanks to their properties to be reversibly opened under hypotonic conditions without losing their natural features and functionalities, represent intravascular carriers for drugs, biologics and other therapeutic agents [3]. Recently, the potential of RBCs loaded with 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 [4]. Since not all iron oxide nanoparticles can be efficiently encapsulated into RBCs, depending on several factors such as dispersant agent nature and nanoparticle size [5], it is very important to identify those nanoparticles potentially eligible for loading into red blood cells in order to produce SPIO-RBCs carriers that can be used as new intravascular imaging contrast agents in biomedical applications. Here, we report preliminary results obtained applying the RBC loading procedure to a new ferucarbotran nanoparticle suspension, similar to Resovist (Bayer), and provided by TOPASS Clinical Solution. Moreover, the potential of RBCs loaded with these nanoparticles has been investigated as a tracer material for MPI.