PEM layer-by-layer systems for coating substrates to improve bioactivity and biomolecule delivery

A coated medical implant device, comprising:

• a biodegradable magnesium-based substrate;
• a pretreatment agent selected from the group consisting of alkali metal hydroxide, hydrogen fluoride and combinations thereof, applied to a surface of the biodegradable magnesium-based substrate to form a charged substrate having a positive charge or a negative charge;
• a polyelectrolyte multilayer coating deposited on the charged substrate, comprising:
• a plurality of interfacing, individual polymer layers, comprising:
• one or more synthetic polymer layers comprising poly-L-lysine having a positive charge;
• and
• one or more natural polymer layers comprising alginate having a negative charge,
• wherein an initial layer of the plurality of interfacing, individual polymer layers deposited on the charged substrate and the charged substrate have opposite charges, and
• wherein the plurality of interfacing, individual polymer layers has alternating layers of the one or more synthetic polymer layers and the one or more natural polymer layers;
• and
• an outer polymer layer comprising one of the one or more natural polymer layers comprising alginate;
• a chemical cross-linking agent comprising a solution of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride with N-hydroxysulfosuccinimide sodium salt, deposited on the outer polymer layer to immobilize fibronectin and form a modified outer surface;
• fibronectin immobilized on the modified outer surface;
• and
• an active substance, in addition to the fibronectin, deposited on the modified outer surface.