Lectin-Gd-loaded chitosan hydrogel nanoparticles: a new biospecific contrast agent for MRI.
Non-specific extracellular contrast agents have been on the market for more than 15 years. Here, we report on the synthesis of new selective lectin-gadolinium (Gd)-loaded chitosan nanoparticles with a prolonged clearance time and a much higher relaxivity in comparison to other preparations. Chitosan nanoparticles were prepared from 85% deacetylated chitin by glutaraldehyde cross-linking of an aqueous acetic acid dispersion of chitosan in a mixture of n-hexane using sodium bis(ethylhexyl)sulfosuccinate as a surfactant. Several crucial parameters, namely, the Gd and protein content of the nanoparticles, their size and dispersity were determined. Magnetic resonance measurements were carried out by intravenous perfusion of mono-disperse suspensions of the nanoparticles into mice. Chitosan nanoparticles can be used as contrast agents in magnetic resonance imaging (MRI). They are excellent candidates for controlled delivery of bioactive compounds to molecular targets and as biospecific diagnostic tools in MRI.