Cu²⁺-doping of polyanionic brushes: A facile route to prepare implant coatings with both antifouling and antibacterial properties

Infections strongly reduce the success rate of implant-related medical procedures. The incorporation of anti-bacterial implant coatings can reduce the chance of infection. However, most of these coatings do not repel bacteria, such that dead bacteria stay on the surface and the performance of these coatings degrades. Ideally, implant coatings should repel bacteria and inhibit bacterial growth in the event of attachment. Unfortunately, the preparation of such coatings often involve complex and expensive synthesis steps, or rely on antibiotics. In this article, we present a simple, inexpensive and robust technique to prepare implant coatings without the use of antibiotics. Our coatings have both anti-fouling and anti-bacterial properties, such that bacteria do not stick to the implant surface and are killed when they come into contact. The coating is composed of poly(3-sulfopropyl methacrylate potassium salt) (Cu@PSPMAK) polymer brushes doped with copper ions (Cu²⁺). The Cu²⁺ in the Cu@PSPMAK coating enables an excellent antibacterial efficiency against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), while the PSPMAK polymer brushes in the coating effectively repel the (dead) bacteria. We show using both in vitro and in vivo tests that the Cu@PSPMAK coating is indeed very effective in avoiding implant-related infections. Moreover, the tests show that the Cu@PSPMAK coating is also biocompatible and accepted within the body. All this makes the Cu@PSPMAK coating an ideal solution for combatting bacterial infections at implants.