Targeting aptamer for atherosclerosis and preparation method and application thereof

A method for preparing a MRI targeting nano-contrast agent for atherosclerosis,

• wherein the MRI targeting nano-contrast agent for atherosclerosis comprises a targeting aptamer for atherosclerosis and a vector connected to the targeting aptamer for atherosclerosis, wherein the targeting aptamer for atherosclerosis is a targeting aptamer fragment for atherosclerosis obtained through screening of macrophage-derived foam cells together with reverse screening of smooth muscle cells, endothelial cells, and THP-1 cells using a SELEX method;
• wherein the targeting aptamer is SEQ ID No:
• 1 or SEQ ID No:
• 2;
• wherein the vector is a silane coated ferriferrous oxide nanoparticle vector;
• the targeting aptamer for atherosclerosis is covalently connected to the silane in the vector via glutaral as a bridge;
• wherein the method comprises the following steps:
• 1) preparing the silane coated ferriferrous oxide nanoparticle vector:
• using ferric chloride and ferrous sulfate as raw materials, refluxing the ferric chloride and ferrous sulfate under a nitrogen atmosphere, after refluxing, separating out ferriferrous oxide using a magnet, and refluxing the ferriferrous oxide with silane, after the reaction, obtaining a silane coated ferriferrous oxide nanoparticle vector by a separation using the magnet;
• 2) synthesizing of a contrast agent:
• washing the silane coated ferriferrous oxide nanoparticle vector obtained in step 1) with water and an alcohol alternately, dissolving a targeting aptamer and the silane coated ferriferrous oxide nanoparticle vector in at least one PBS solutions respectively, then adding the PBS solution of the targeting aptamer for atherosclerosis into the PBS solution of the silane coated ferriferrous oxide nanoparticle vector, and adding a glutaral, placing on a shaking table for vibration;
• separating a product with a magnet, removing the supernatant, and washing with the PBS solution.