A Nanoporous Cytochrome c Film with Highly Ordered Porous Structure for Sensing of Toxic Vapors

Creating well‐ordered nanoporosity in biomolecules promises stability and activity, offering access to an even wider range of application possibilities. Here, the preparation of nanoporous protein films containing cytochrome c protein molecules is reported through a soft‐templating strategy using polystyrene (PS) spheres of different sizes as templates. The stability of the cytochrome c film is demonstrated through electrochemistry studies to show a reusable nature of these films over a long period of time. The size of the PS spheres is varied to tune the pore diameter and the thickness of the cytochrome c films, which are quite stable and highly selective for sensing toxic acidic vapors. The fusion of the templating strategy and the self‐assembly of biomolecules may offer various possibilities by generating a new series of porous biomolecules including enzymes with different molecular weights and diameters, peptides, antibodies, and DNA with interesting catalytic, adsorption, sensing, and electronic properties. Highly ordered nanoporous protein films containing cytochrome c molecules are prepared through the soft‐templating strategy, displaying superior stability and selective sensing for toxic organic acid vapors. Quartz‐crystal microbalance (QCM) characterization for the nanoporous film with a pore size of 200 nm exhibits a highly selective sensing for toxic acidic vapors.