A method for forming a mold insert includes forming a stamp, a surface of the stamp including a plurality of inverted microstructures formed thereon; and pressing the stamp into a medium disposed on a surface of a first mold insert to form a microstructured film, the microstructured film including a plurality of microstructures formed on a surface of the microstructured film based on the plurality of inverted microstructures, the plurality of microstructures being complementary to the plurality of inverted microstructures.