In some embodiments, a micromechanical filter includes multiple subfilters, each subfilter comprising multiple piezoelectric resonators mechanically coupled in series, wherein the subfilters are mechanically coupled to each other in parallel. The two different gate electrodes include a first gate electrode on a first gate insulation layer. The substrate is heated in the substrate heating step so that the Leidenfrost phenomenon occurs and steam of the cleaning fluid is interposed between the substrate and droplets of the cleaning fluid supplied to the substrate in the cleaning fluid supply step. The solid material having immobilized proteorhodopsin is deposited on a substrate selected from the group consisting of glass, paper, metal, fabric material, plastic material, and used as an optical data storage material or a fraud-proof carrier.