Dear B.s. Bini ! Are the pores in the silica gel large enough? If the enzyme and substrate molecules are placed in pairs, then you can safely proceed to immobilization.
There are several ways to immobilize amylase on silica gel. To do this, it is necessary to fix the amylase with chemical bonds. Covalent bonds and ionic bonds are suitable. Ionic bonds are more convenient. Check out my post.Patent Method of hydrolysis of biological substrates