Preparation of gelatin microspheres: add gelatin aqueous solution to a four-mouth bottle with a stirrer, thermometer and reflux condenser, then add polymethyl methacrylate (PMMA) concentrated solution, stir to make it a uniform emulsion, add glutaraldehyde/toluene saturated solution, cross-link reaction at room temperature, after the reaction is over, repeatedly wash with an organic solvent, centrifuge to remove the polymer, and then wash and centrifuge with acetone and water for multiple times, red-brown gelatin microspheres were obtained, sieved and freeze-dried.
Combination of anti-cancer drugs and microspheres: The microspheres prepared by the above method contain a large amount of free aldehyde, which is easy to form covalent binding with the anti-cancer drugs AD or MMC containing amino groups. The frozen microspheres are weighed and added to the concentrated solution of AD or MMC with known concentration respectively. At 4 ℃, the microspheres are slowly stirred and reacted for 24 hours. After that, they are repeatedly washed with physiological saline, centrifuged and separated, and all the clear liquid in the upper layer is collected.
GM carrier was treated with glycine or ethanolamine, its active aldehyde group was sealed, lyophilized and weighed respectively, added into AD and MMC concentrated solution, soaked for 24 hours, and the combined amounts of physical adsorption AD and MMC were 27.1 μg/mgGM and 38.2 μg/mgGM respectively.