Identification of the Safe(r) By Design alternatives of Nanosilver-enabled wound dressings

Background, Motivation and Objective The use of silver nanoparticles (NPs) in medical devices has increased due to their excellent antimicrobial properties. In wound dressings, Ag NPs are commonly added in large excess to exert long-term and constant antimicrobial effects, which can cause instantaneous release of Ag ions or the persistence of unused NPs in the wound dressing that can be unintentionally released during the end-of-life stage to pose risks for ecosystems. Statement of Contribution/Methods To address these challenges, a Safe-by-Design procedure was developed in order to reduce potential environmental risks while optimizing the functional performance and the costs of wound dressings containing Ag NPs. The SbD procedure is based on a set of ad-hoc criteria (e.g., mechanical strength, antibacterial effect, leaching of Ag from the product immersed in environmental media) and permit to identify the best alternative among five pre-market alternatives which differ in i) the polymer matrix used, ii) the type and iii) the quantity of Ag NPs incorporated in the wound dressings. Results/Discussion A ranking of the SbD alternatives was obtained and the safest solution (i.e., a wound dressing made with electrospun fibres of Poly L-lactide polymer and Ag NPs coated with hydroxyethyl cellulose) was selected based on the SbD criteria (Figure 1). The SbD procedure was also applied to commercial wound dressings to compare SbD alternatives with products already on the market. The proposed procedure proved to be effective in identifying underperforming alternatives to be excluded from further developments (based on its low mechanical strength) and in supporting the ranking and prioritization of safer alternatives early in the innovation process.