Versatile and sustainable nanocolloids of Au@tannic acid coordinated with Fe(III) ions for layers deposition on the plasmochemicaly activated Ti6Al7Nb alloy

• The preliminary treatment in the PA RF CVD reactor contributed to proper cleaning and activation of the alloy surface allowing for formation of coatings with suitable adhesion and durability. • The addition of Au@TA NPs complexed with Fe(III) ions contributed to the development of novel inorganic-organic hybrid coatings with antioxidant effects, antibacterial properties and biocompatibility. • The use of additional biopolymers such as hyaluronic acid and chitosan in the top layer positively influenced the biocompatibility of the resulting coatings. • Au@TA NPs and Au@TA_Fe(III) NPs exhibit non-cytotoxicity (Saos-2 cell line) with potent bacteriostatic activity at the doses tested ( E. coli, B. paramycoides ) in vitro. • The additive action of all components combines different modes of antimicrobial action, reducing the chances of acquiring bacterial resistance. The rejection of implanted orthopaedic devices is often associated with the formation of bacterial biofilm on their surface, which results in a slow process of tissue regeneration surrounding the implant, as well as poor osteointegration. Proper functionalization of the surface of orthopaedic implants could help mitigate this problem. This study focused on the surface modification of the medical alloy Ti6Al7Nb through plasma-chemical treatment (PA RF CVD – Plasma Activated Radio Frequency Chemical Vapour Deposition ) and post-deposition of bioactive coatings involving Au nanoparticles derived from the reductive action of tannic acid and complexed with Fe(III) ions. The plasma-chemical process using Ar-O 2 mixture contributed to surface activation and increased the oxygen content in the outer layer. Whereas, the introduction of additional top biopolymeric coating (chitosan, hyaluronic acid) positively influenced the biocompatibility of the resulting coatings. The resulting coatings are chemically stable with no signs of delamination. Moreover, in vitro studies revealed biocompatibility (Saos-2 cell line) with prospective bacteriostatic activity at the doses tested ( Escherichia coli, Bacillus paramycoides ) . The development of novel inorganic-organic hybrid coatings with antioxidant activity, antibacterial properties, and biocompatibility indicates good prospects for the use of these coatings in implantology. Au nanoparticles, derived from the reductive action of tannic acid and complexed with Fe(III) ions, contributed to the development of novel inorganic-organic hybrid coatings with antioxidant effects, antibacterial properties and biocompatibility.