Engineering Antifouling and Antibacterial Stainless Steel for Orthodontic Appliances through Layer-by-Layer Deposition of Nanocomposite Coatings.

In this study, a nanocomposite coating composed of polydopamine, functionalized poly(3,4-ethylenedioxythiophene) (PEDOT), and silver nanoparticles (AgNPs) was synthesized through layer-by-layer deposition. Biomimitic polydopamine and hydroxyl-functionalized PEDOT were used to enhance the adhesion strength. The deposition of PEDOT functionalized with zwitterionic phosphorylcholine can contribute to the antifouling property. After immersion in the AgNO 3 solution, Ag + ions were adsorbed on PEDOT films and further reduced to form AgNPs spontaneously, which conferred antibacterial properties on these nanocomposite films. Escherichia coli and Streptococcus mutans were chosen to represent two common Gram-negative and Gram-positive oral pathogens. We further conducted inductively coupled plasma mass spectrometry to confirm that the Ag + ions released from these nanocomposite films did not exert adverse effects on the human body. These results suggested that, when applied to stainless steel orthodontic appliances, these durable antifouling and antibacterial coatings may be useful for avoiding bacterial infection.