Lactoferrin-polyphenol composite nanocoating with enhanced chemical stability and cell-compatibility

Lactoferrin is a functional whey protein that exhibits beneficial bioactivities to human health. To utilize the wide range of lactoferrin's biomedical advantages, much effort has been devoted to developing lactoferrin coating strategies. However, lactoferrin coating has been still limited to the conventional protein modification techniques, which hamper the practical applications of lactoferrin. Here, we demonstrate lactoferrin composite nanocoating by layer-by-layer assembly with lactoferrin and Fe(III)-tannic acid complex. The simple immersive processes are able to deposit lactoferrin composite nanolayers on planar substrates with precise thickness tuneablility. Also, the optimized deposition condition for lactoferrin composite nanocoating is applicable to particulate substrates. Further, lactoferrin composite nanocoating shows enhanced nanofilm stability against pH changes and digestive enzyme treatments, and improves cell compatibility greatly, compared to that of Fe(III)-TA complex. We envisage that lactoferrin composite nanocoating not only paves the way for exploiting full potential of lactoferrin's bioactivities, but also leads to stimulating the tailored design of composite nanomaterials containing multiple enzymes for customized applications in nanomedicine and nanobiosensor.