Treatment Activity on Metastatic Bone Tumor by Methotrexate-Loaded Co(II) Metal–Organic Frameworks Encapsulated in Hydrogels

In the present study, a new Co(II)-based coordination polymer with the chemical formula of [Co(H 3 L)(bpe) 0.5 ] · H 2 O] (1; H 3 L = 4-(2′,3′-dicarboxylphenoxy) benzoic acid, bpe = 1,2-bis(4-pyridyl) ethylene) was prepared and successfully loaded with methotrexate using the mixed-ligand synthesis approach. Hyaluronic acid/carboxymethyl chitosan hydrogels loaded with Co(II) metal–organic frameworks were prepared by chemical synthesis to further control the release of methotrexate. Scanning electron microscopy showed that the hydrogels had a continuous porous structure with pore sizes concentrated in 206–357 μ m. Results of real-time polymerase chain reaction indicated that the hydrogels could remarkably reduce the abnormally increased levels of Flt-1 and Flk-1 in bone tumor peripheral blood vessels. Besides, IGF content was reduced obviously under the treatment of the new hydrogels in a dose and time-dependent manner. Therefore, the hydrogels loaded with Co(II) metal–organic frameworks are expected to be applied in the clinical treatment of bone tumors.