The present invention provides, among other things, multilayer film coating compositions, coated substrates and methods thereof In some embodiments, a structure, comprising a substrate and a multilayer film on the substrate, wherein the multilayer film comprises a first plurality of first units, each first unit comprising a protamine polypeptide. In some embodiments, a structure comprising a microneedle substrate and a multilayer film coated on at least portion of the microneedle substrate, wherein the multilayer film comprises an agent for release and a first plurality of first unit; each first unit comprising a first layer and a second layer, wherein the first layer and the second layer are associated with one another.