Release of a model protein from biodegradable self assembled films for surface delivery applications

Layer-by-layer (LbL) films have multiple features that make them attractive for drug delivery, including the potential to sequentially deliver growth factors from implantable medical devices or tissue engineering scaffolds. To date, however, characterization has been lacking for protein delivery from such films. Here, LbL polyelectrolyte films constructed with the model protein lysozyme and a hydrolytically degradable and biocompatible synthetic polycation are characterized. Milligram/cm2 scale linear or power law release profiles can be achieved over 2 to 34 days, and control over loading and release are demonstrated through parameters such as tuning the degradability of the synthetic polycation, changing the number of layers used, or changing the polysaccharide polyanion. Functionality is maintained at nearly 100%, underscoring mild processing conditions apt to preserve fragile protein function. LbL films thus have promise as a tool for exploring protein modulation of the interaction between implanted surfaces and the cells they contact.