Development by emulsion templating of a novel Tunisian clay-polyvinyl alcohol/extra-virgin olive oil scaffold with antibiofilm properties

Abstract

A biobased porous scaffold with antibacterial and antioxidant properties was developed using the emulsion templating method. This technique represents a new route for the development of porous materials with controllable pore size. To take into account the environmental and economic aspects, polyvinyl alcohol (PVA) was chosen as the polymer matrix, raw Tunisian clay as the Pickering emulsion stabilizer, and extra virgin olive oil (EVOO) as the oil phase. PVA is often chosen for producing wound dressings that create a moist environment and consequently promote healing. Clay was used as a barrier against bacteria and as emulsifier due to its nanoscale and layered structure. In EVOO, the polyphenolic compounds have antioxidant activity and fatty acids have a plasticizer role. X-ray fluorescence, X-ray diffraction and Fourier transform infrared spectroscopy were used to analyze the raw clay. Then, the obtained films were structurally and chemically characterized, and their performance, antimicrobial activity against Pseudomonas aeruginosa, and antioxidant activity were evaluated. The emulsion characterization showed that clay addition influenced the emulsion type and increased the emulsion stability index to 98%, even after 3 months of storage. This was explained by the irreversible adsorption of clay platelets on the droplet surface that formed a rigid shell to prevent coalescence. The film characterization demonstrated that the oil: water ratio did not influence the surface porosity, although it affected the pore size uniformity and interconnection. Conversely, shortening the curing time improved the surface porosity. The resulting PVA-clay/EVOO scaffold displayed an exceptional performance, including high mechanical strength (∼2.1 MPa), interconnected porous structure with a size ranging from few µm to > 30 µm, and hydrophobic properties (∼90° ± 2). In addition, it showed antiadhesive and antibiofilm activities against P. aeruginosa. Therefore, this scaffold could be used for the early prevention of biofilm formation during wound healing and is a promising candidate for the controlled release of drugs and potentially for various applications in soft tissues.