Revolutionary 3D-printed vertebral device with antibacterial silver-based nanocoatings for bone regeneration and antibacterial action

Spinal orthopedic infections, with incidence rates of 15–20%, pose a significant challenge. To prevent this complication, metal-based antibacterial coatings are widely used. However, current coatings have several drawbacks, with possible toxicity or impaired osteointegration. This study aimed at evaluating the use of nanostructured silver-based coatings to provide antibacterial efficacy to 3D printed custom-made porous spine prostheses. Coatings were obtained by Ionized Jet Deposition, which guarantees nanostructuring and nanoscale thickness, both of which help avoid toxicity. To further mitigate interference with bone regeneration, the silver (Ag) was mixed with bone apatite (Bone). Deposition technique was also optimized for future industrial scale-up, and application to a real-scale prosthesis is demonstrated. Our results showed that all the films were nanostructured and maintained the same composition as the target. The real-size device was effectively coated, also in the inner areas, potentially discouraging microbial contamination onto the entire device. Ag and Ag-Bone films demonstrated remarkable in vitro efficacy against gram-positive and gram-negative bacteria, with no observed cytotoxicity. Both Ag and Ag-Bone apatite films showed significant bacterial inhibition activity also in an in vivo model infected with the Methicillin-Resistant Staphylococcus aureus USA 300 strain, demonstrating their promising future applications for tackling infection associated with spine devices.