Immobilization of lysozyme on layer-by-layer self-assembled electrospun nanofibers treated by post-covalent crosslinking

In this study, lysozyme and dextran sulfate sodium salt (DS) were alternately deposited on the surface of electrospun cellulose acetate (CA) nanofibers, which were then heated at 55 °C for 6 days to induce crosslinking via Maillard reaction . The non-heated self-assembled nanofibers presented the increased average fiber diameter from 397 to 501 nm with increasing number of layers, but an improved thermal stability was induced by Maillard reaction due to the formation of covalent bonds. After heating, the immobilized lysozyme lost less than 40% of its initial activity, but exhibited the enhanced temperature tolerance and storage stability, and retained over 55.6% of its original activity after 12 reuses. Moreover, the heated nanofibrous mats showed substantially higher antibacterial activities against Staphylococcus aureus and Escherichia coli , compared to the non-heated ones. These results suggested the promising applications of the post-covalent layer-by-layer (LBL) nanofibrous mats in improving enzyme performance in food , pharmaceutical or personal care products.