Direct Plasma Deposition of Lysozyme-Embedded Bio-Composite Thin Films

Bio-composite coatings, consisting of an organic matrix embedding a bioactive molecule, havebeen deposited by means of atomizer-assisted atmospheric pressure plasma. Ethylene waschosen as the precursor of the matrix, while the atomizer was fed with a water solution oflysozyme. Coatings chemical composition was investigated by XPS, FTIR and MALDI-TOFspectroscopies, and it has been proved that the one-step inclusion of protein domains inthe composite coatings is successful and lysozymechemical structure is only slightly altered. The amountof embedded lysozyme is as high as 14mg/cm2asevaluated from water release test. Finally, the activityof the plasma-embedded protein is close to that of purelysozyme as verified againstMicrococcus lysodeikticusATCC 4698 through an agar plate diffusion test