Gd(DOTA)-grafted submicronic polysaccharide-based particles functionalized with fucoidan as potential MR contrast agent able to target human activated platelets.

•Polysaccharide matrix contained both fucoidan and dextran gadolinium macrocomplex.•A simple and green water-in-oil emulsification/crosslinking method was developed.•Particles are cytocompatible with human endothelial cells.•Particles successfully targeted activated human platelets via fucoidan/P-selectin interactions.•Dual T1/T2 relaxation properties were confirmed on MRI phantoms.