Drug-eluting biodegradable metals and metal-ceramic composites

Biodegradable metals emerged as promising temporary bone implants. The integration of local drug delivery (LDD) can prevent biomaterial-centered infections that are difficult to treat. LDD is achieved by drug-eluting coatings or porous implants where the drug is impregnated after implant fabrication because the high temperatures used during conventional production processes would result in their thermal decomposition. This work reports on the production and characterization of vancomycin hydrochloride (VH)-loaded Fe and Fe-iron oxide (Fe2O3) composites (Fe-Fe2O3) by a cold sintering technique. We use focused ion beam milling for the first time to investigate the drug-metal interface. We investigate the mechanical and degradation properties of VH-free and VH-loaded Fe and Fe-Fe2O3. Results show very high mechanical strength of drug-eluting Fe and Fe-Fe2O3 composites (up to than 780 MPa under compression, exceeding the maximum strength of cancellous bone more than three times) accompanied by a delayed drug release. Then, we confirm the good antimicrobial activity against Staphylococcus aureus and cell compatibility with the murine embryonic fibroblast cell line NIH/3T3 in vitro. Overall results confirm the promise of drug-eluting metals and metal-ceramic composites for LDD in bone.