Exploration of Atmospheric Pressure Plasma Nanofilm Technology for Straightforward Bio-Active Coating Deposition: Enzymes, Plasmas and Polymers, an Elegant Synergya

While protein or enzyme immobilization methodologies are readily applicable in a majority of industrial processes, some lacunas still remain. For example, the multi-step, wet-chemical nature of current immobilization reactions limits straightforward bio-film fabrication in continuous production units. As such, a fast and preferably single step immobilization technique, minimizing solvent use and decoupling deposition substrate from used method is awaited. In this research, an atmospheric pressure plasma reaction environment is chosen for its flexibility in terms of reactivity and the ease of coating depositions on a wide variety of substrates. Organic coating precursors such as acetylene or pyrrole are injected simultaneously with an atomized enzyme solution directly in the discharge. By atomizing the enzyme solution, the enzyme molecules are surrounded by a watery shell. It is envisioned that such droplet act as "shuttles", delivering the enzymes to the discharge while protecting them from the harsh plasma conditions. In the discharge, polymerization of the added organic coating precursor takes place and consequently, the enzyme molecules become trapped in the growing polymer network. In addition, atomization of the protein solution favors the spatial distribution of the proteins in the coating. Several enzymes are evaluated and enhanced temperature and solvent stability is observed. Moreover, single molecule fluorescence, enzyme activity and bio-recognition experiments demonstrate protein integrity after plasma assisted immobilization.