In this PoC project, we have successfully developed antimicrobial catheter and door-handle prototypes, both made with coatings of the polymer polyurethane that incorporates the porous MOF loaded with iodine (hereafter named I2@UiO-66). Initially, we optimized the formulation of the antimicrobial coatings using a biocompatible, non-porous polyurethane-based polymer for incorporating spherical I2@UiO-66 composites. Cross-sectional analysis of the coatings revealed two distinct regions. In the first region, I2@UiO-66 composites were almost uniformly dispersed within the polyurethane-based polymer, constituting the active region. In the second region, identified as the polymeric region, I2@UiO-66 composites were sparce. This polymeric region is presumed to impart the required adhesiveness and elasticity characteristics for effective coatings utilization.
The resulting coatings were experimentally observed to have low brittleness and high adhesiveness, making them highly suitable for coating applications. The release of iodine from the coatings was characterized as burst biphasic, exhibiting an initial burst release followed by a controlled release through hindered Fickian diffusion. This controlled release was well-described by the semiempirical Korsmeyer-Peppas model. According to this model, the calculated lifetime of the coatings is 147 days.
Subsequently, we evaluated the antimicrobial activity of both catheter and door-handle SAFE-ON prototypes. All the films were assessed 12 h after preparation to avoid testing during the initial burst release phase. The prototypes underwent consistent testing against Gram-positive bacterial species (Staphylococcus aureus, and Enterococcus faecalis), Gram-negative bacterial species (Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii), and yeast (Candida albicans). These prototypes demonstrated effective inhibition against all the tested microorganisms.
Finally, we conducted cytotoxicity assays to ensure that the catheter and door-handle SAFE-ON prototypes meet safety requirement and do not pose any issue associated with excessive iodine administration. The results indicated that the prototypes do not raise safety concern.
In conclusion, we have successfully developed catheter and door-handle prototypes based on ptimized SAFE-ON coatings, demonstrating a broad-spectrum antimicrobial activity, a substantial lifetime of up to 147 days, and no secondary safety concern.
