Natural Silk Film for Magnesium Protection: Hydrophobic/Hydrophilic Interaction and Self-Healing Effect

Biodegradable implants are required in order to provide successful treatment of injuries. Temporary magnesium-based implants with particular properties are needed in cases when it is desirable not only to maintain vital activity, but also to initiate the self-healing process of damaged bones or tissues as well. Unfortunately, the use of magnesium alloys is limited due to the fast biodegradability of the applied material. The aim of this research is to improve the corrosion resistance of magnesium alloys by sonochemical treatment in silk solution followed by additional layer-by-layer deposition of natural silk on the magnesium surface. The sonication process is carried out at a frequency of 20 kHz during 5-10 min, while the duration of the silk layer deposition is 15 min. The corrosion behavior of magnesium substrates modified by natural silk layer-by-layer assembly is studied. Magnesium substrates sonochemically treated in silk solution demonstrate three times better corrosion resistance compared to control samples sonochemically treated in water. Additional deposition of a silk layer enhances obtained corrosion resistance by 18 times, resulting in a 54-fold increase overall.