Antifouling properties of electrospun polymeric coatings induced by controlled surface morphology

Nosocomial infections affect implanted medical devices and greatly challenge their functional outcomes, becoming sometimes life threatening for the patients. Therefore, aggressive antibiotic therapies are administered, which often require the use of last-resort drugs, if the infection is caused by multidrug- resistant bacteria. Reducing the risk of bacterial contamination of medical devices in the hospitals has thus become an emerging issue. Promising routes to control these infections are based on materials provided with intrinsic bactericidal properties (i.e., chemical action) and on the design of surface coatings able to limit bacteria adhesion and fouling phenomena (i.e., physical action), thus preventing bacterial biofilm formation. Here, we report the development and validation of coatings made of layer-by-layer deposition of electrospun poly(vinylidene fluoride-co-trifluoro ethylene) P (VDF-TrFE) fibers with controlled orientations, which ultimately gave rise to antifouling surfaces. The obtained 10-layer surface morphology with 90° orientation fibers was able to efficiently prevent the adhesion of bacteria, by establishing a superhydrophobic-like behavior compatible with the Cassie-Baxter regimen. Moreover, the results highlighted that surface wettability and bacteria adhesion could be controlled using fibers with diameter comparable to bacteria size (i.e., achievable via electrospinning process), by tuning the intra-fiber spacing, with relevant implications in the future design of biomedical surface coatings.