Protein-containing hydrophobic coatings and films

The incorporation of enzymes and other proteins into hydrophobic polymeric coatings and films has been investigated in this study with the goal of generating biologically active materials for biocatalysis, antifouling surfaces, and biorecognition. The protein–polymer composites are created using standard solution coating techniques with poly(methyl methacrylate), polystyrene, and poly(vinyl acetate) as polymers and α-chymotrypsin and trypsin as biocatalysts. The specific enzyme is first extracted into a nonpolar organic solvent using hydrophobic ion-pairing. The ion-paired enzyme is dried and redissolved into a solvent also miscible with the polymer. This solution is then poured over a surface and the solvent is allowed to evaporate to form the enzyme-containing coating, which can then be delaminated to form a film. Leaching of enzyme from and activity of the biocatalytic coatings and films were evaluated. The biocatalytic coatings showed no loss of activity over ca. one week. For the biocatalytic films, the leaching rate was initially high followed by a slow rate of enzyme loss. Activity was measurable for at least one month, with only ca. one-third of the initial activity lost in that time, while, being continuously incubated in a buffer solution. Activity was also exhibited on macromolecular (protein) substrates. The biocatalytic coatings could be reused over 100 times with only a modest loss of activity. Finally, coatings and films containing a lectin (Concanavalin A) were capable of selectively binding to glycoproteins, thereby extending the application of such films for use in bioseparations and biorecognition.