In-situ electrophoretic deposition (EPD) and anti-solvent precipitation of tannic acid-loaded zein particles, copper-doped bioactive glass, and sodium carboxymethyl cellulose coatings for orthopedic applications

Abstract

To endow metallic implants with antibacterial and bioactive properties while avoiding the complications of conventional antibiotic treatment, such as antibiotic resistance, biofilm formation, and host toxicity, the application of multifunctional coatings with tailored drug release capacities on the implant surface could be explored. In this context, the current study focuses on the preparation of multicomponent coatings composed of tannic acid (TA)-loaded zein particles and copper-doped bioactive glasses (CuBG) embedded within a polysaccharide matrix of sodium carboxymethyl cellulose (CMC) on titanium. A novel in-situ process of combined anti-solvent precipitation and electrophoretic deposition (EPD) was exploited to simultaneously synthesize and deposit the drug-loaded zein particles together with the bioactive agent (CuBG) and the polymeric coating matrix (CMC). Compared to the conventional methods to produce coatings containing drug-loaded polymer particles by multi-step EPD, the proposed approach offers time efficiency, versatility, and controlled drug release rates. The results showed that the encapsulation of the phytotherapeutic drug in the zein particles leads to a sustained drug release from the coatings, while CuBG induces a bioactive response in the physiological environment. Furthermore, the combination of tannic acid-loaded zein particles and CuBG in the CMC-based coatings results in high cytocompatibility with pre-osteoblast MC3T3-E1 cells and a synergistic antibacterial activity against S. aureus and E. coli. The obtained outcomes suggest that the produced coatings can potentially enhance bone tissue integration and prevent infections around orthopedic implants.