Engineered Implants with Smart and Sustained Release of Antimicrobial Agents

Infections caused by microorganisms during implant-mediated tissues regeneration therapy can lead to further complications and ultimate failure of the healing process. Therefore, an implant empowered with controlled and sustained release of antimicrobial agents is highly desired for tissue engineering applications. Here, we present a novel antibacterial film for wound healing applications constructed from metal organic frameworks (MOFs) and polymers for a sustained release of antimicrobial agents. Cyclodextrin metal organic frameworks (CD-MOFs) are embedded into biodegradable and biocompatible polymers, polycaprolactone (PCL) and polyethylene oxide (PEO). The concentration of polymers and MOFs was carefully optimized to obtain a highly flexible and strong film with a thickness of about 500 µm . The γ-CD-MOFs have been extensively exploited for their applications in biomedicine due to the biocompatible nature of its building blocks, i.e. γ-cyclodextrin and potassium ions. CD-MOFs possess two types of highly organised channels, hydrophilic (1.7 nm) pores resulted from CD coordination with potassium and inherent hydrophobic cavities (0.9 nm) of CD itself. However, their real potential in pharmaceutical sector is compromised due to their susceptible nature to water and poor processability of CD-MOF powder. In this work, cavities of CD-MOFs were utilised by <i>in situ</i> synthesis of ultra-small silver nanoparticles (AgNPs) with an average size of 2-5 nm. CD-MOFs. The optimised maximum concentration of CD-MOFs in the resulted film is 10% (w/w) with homogenous distribution of CD-MOFs nanoparticles. The CD-MOFs film shows a moisture triggered sustained release of AgNPs for more than 72 hr. The antimicrobial efficacy of the film was tested against E.Coli, S.aureus, and, and fungi Candida using zone of inhibition diameters (ZOI) and the results were 0.87 ± 0.06, 1 ± 0.1 and 0.97 ± 0.15 cm. The novel CD-MOFs film shows a great potential to be used as an antimicrobial film for the sustained release of antimicrobial agents in biomedical applications.