In this research, we used acid hydrolysis to prepared two different molecular weight fucoidan, the small molecular fucoidan (Fus) as drug, and the molecular weight approximately 1 kDa fucoidan (Ful) as the nanoparticle gatekeeper, and as targeting molecule for overexpressed P-selectin on the surface of the metastatic tumors. Here, SELP is linked to metastatic neoplasm.