A Precautionary Approach to Guide the Use of Transition Metal-Based Nanotechnology to Prevent Orthopedic Infections

Abstract

The increase of multidrug-resistant bacteria remains a global concern. Among the proposed strategies, the use of nanoparticles (NPs) alone or associated with orthopedic implants represents a promising solution. NPs are well-known for their antimicrobial effects, induced by their size, shape, charge, concentration and reactive oxygen species (ROS) generation. However, this non-specific cytotoxic potential is a powerful weapon effective against almost all microorganisms, but also against eukaryotic cells, raising concerns related to their safe use. Among the analyzed transition metals, silver is the most investigated element due to its antimicrobial properties per se or as NPs; however, its toxicity raises questions about its biosafety. Even though it has milder antimicrobial and cytotoxic activity, TiO2 needs to be exposed to UV light to be activated, thus limiting its use conjugated to orthopedic devices. By contrast, gold has a good balance between antimicrobial activity as an NP and cytocompatibility because of its inability to generate ROS. Nevertheless, although the toxicity and persistence of NPs within filter organs are not well verified, nowadays, several basic research on NP development and potential uses as antimicrobial weapons is reported, overemphasizing NPs potentialities, but without any existing potential of translation in clinics. This analysis cautions readers with respect to regulation in advancing the development and use of NPs. Hopefully, future works in vivo and clinical trials will support and regulate the use of nano-coatings to guarantee safer use of this promising approach against antibiotic-resistant microorganisms.

Novel Silver-Functionalized Poly(ε-Caprolactone)/Biphasic Calcium Phosphate Scaffolds Designed to Counteract Post-Surgical Infections in Orthopedic Applications

“…A foreign body is the triggering event for biomaterial-associated infections (BAIs) because certain features of a biomaterial, such as its surface and roughness characteristics, not only attract host eukaryotic cells involved in tissue regeneration, but also free-floating bacteria. Indeed, as soon as a contamination occurs, the “race to the surface” takes place, followed by microorganism adhesion and subsequent biofilm formation, which are important in determining the occurrence of infection [ 7 , 17 , 32 ].…”

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“…"biological window" for which soft tissues are somewhat transparent. Other nanomaterials also exhibit nonspecific cytotoxic properties (e.g., nanosilver) through a variety of chemical mechanisms, but a general problem with the application of nanomaterials against bacterial infections is their lack of specificity against bacterial vs. mammalian cells, presenting a general challenge for biocompatibility (25).…”

Antibacterial and Anti-Inflammatory Coating Materials for Orthopedic Implants: A Review

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