Mechanically durable antibacterial nanocoatings based on zwitterionic copolymers containing dopamine segments

Developing an effective and durable antibacterial surface is important for surgical tools and biomedical implants. In this work, a zwitterionic copolymer containing catechol groups as biomimetic anchoring segments was coated onto 316 L stainless steel via drop-casting. Energy-dispersive X-ray spectroscopy (EDS) and water contact angle (WCA) measurements indicated that the coatings made of the copolymers containing zwitterionic and dopamine segments at the molar ratios of 8:2 and 6:4 exhibited stronger stability and mechanical durability than the one at 9:1 after inducing tape-peeling and ultrasonication damage. The mechanically durable nanocoatings exhibited excellent antibacterial performance against Staphylococcus aureus and Escherichia coli in a period of 3 days. The nanocoatings with zwitterionic and dopamine segments at the molar ratio of 8:2 were further evaluated and demonstrated durable antibacterial performance after tape-peeling and ultrasonication treatments.