One-step PDA coating strategy on pure Zn for blood-contacting engineering

The mechanical performance degradation caused by pitting corrosion and the insufficient biocompatibility induced with ion release inhibit the application of Zn as the new biodegradable metallic materials for blood-contacting intervention therapy. This work successfully coats a uniform polydopamine (PDA) layer on pure Zn via a one-step deposition process without introducing heavy metal elements or detrimental additives. Enhanced corrosion resistance and uniform corrosion have been performed on PDA coated Zn with corrosion products and pits reduced significantly than pure Zn during in vitro degradation. Thrombosis could be prohibited by anticoagulation performance with prothrombin time and activated partial thromboplastin time prolonged after co-incubation, and an almost 40% decrease of platelets adhesion, indicating the improved blood compatibility of coated Zn. Additionally, the poly (lactic-co-glycolic acid) (PLGA) is filmed on PDA coated Zn to realize a smooth double-coated structure with superior mechanical performance under stress loading to stably serve the multifunctional application, such as drug loading. Our strategy not only represents a facile and biological friendly method for Zn surface modification but also puts forward new ideas on preparing PDA-based coatings on active biodegradable alloys, which are beneficial for better blood-contacting engineering.