Intrinsic Hydrophobic Antibacterial Thin Film from Renewable Resources: Application in the Development of Anti-Biofilm Urinary Catheters

The use of renewable resources to develop functional materials is increasing in order to meet the sustainability challenges. In an era of inexorable evolution of antimicrobial resistance, there is a substantial increase in demand for the development of efficient antimicrobial thin film coating from renewable resources for public bacterial threats, food, biomedical, and industrial applications. In the present investigation, we have used cardanol, a phenolic compound having unsaturated hydrophobic tail isolated from cashew fruits, and linseed oil, a vegetable oil and an important biobased building block, which are cheap and easy to regenerate. This study reports the synthesis of cardanol based metal complexes having unsaturated hydrophobic unit and acrylated epoxidized linseed oil (AELO) prepared via epoxidation of double bonds followed by acrylation. The double bond present in the metal complexes and AELO is prone to form assembled thin film under atmospheric conditions, without the need of any initiators. Assembled thin film is one of the important aspects of nanotechnology holding a wide range of applications. ¹H NMR and FT-IR analysis revealed the existence of a strong interaction between ligand and metal, which paves a way to develop a nonleachable metal based thin film coating. The leaching behavior of thin film coating was investigated under various aggressive conditions with the aid of UV–vis spectroscopy. The mechanical properties of assembled thin film coating material composed of cardanol-based metal complex and AELO are described using oscillatory rheology. Morphological and SAXD analysis clearly revealed the formation of the assembled structure in thin films. Thermal response of these materials has been investigated using TGA and DSC measurements. Intrinsic hydrophobic character was identified by contact angle measurement. Antimicrobial and biofilm inhibitory behavior of synthesized compounds and thin films were investigated against various human pathogenic bacterial strains. The assembled thin film coated catheter tube completely inhibits the biofilm formation of uropathogenic Escherichia coli (UPEC). Thus, the developed thin film coating material holds promise to be used as metal enabled, nonleachable coating materials for public bacterial threats, and food and biomedical applications. In particular, this material can be potentially used for developing urinary catheter tubes with antibacterial properties.