| Summary: | Esca is a type of grapevine trunk disease that severely affects vine yield and longevity. <i>Phaeomoniella chlamydospora</i> (<i>P. chlamydospora</i>) is one of the main fungi associated with esca. The aim of the present study was to obtain eco-friendly materials with potential antifungal activity against <i>P. chlamydospora</i> based on biodegradable and biocompatible poly(3-hydroxybutyrate) (PHB), nanosized TiO<sub>2</sub>-anatase (nanoTiO<sub>2</sub>), and chitosan oligomers (COS) by conjunction of electrospinning and electrospraying. One-pot electrospinning of a suspension of nanosized TiO<sub>2</sub> nanoparticles in PHB solution resulted in materials in which TiO<sub>2</sub> was incorporated within the fibers (design type “<i>in</i>”). Simultaneous electrospinning of PHB solution and electrospraying of the dispersion of nanosized TiO<sub>2</sub> in COS solution enabled the preparation of materials consisting of PHB fibers on which TiO<sub>2</sub> was deposited on the fibers’ surface (design type “<i>on</i>”). Several methods including scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), thermogravimetric analyses (TGA) and water contact angle were utilized to characterize the obtained materials. The incorporation of nanoTiO<sub>2</sub> in the PHB fibers, as well as nanoTiO<sub>2</sub> deposition onto the surface of the PHB fibers resulted in increased roughness and hydrophobicity of the obtained composite fibrous materials. Moreover, TiO<sub>2</sub>-<i>on</i>-PHB fibrous material exhibited complete inhibition of fungal growth of <i>P. chlamydospora</i>. Therefore, the obtained eco-friendly fibrous materials based on PHB and nanoTiO<sub>2</sub> are promising candidates for protection against esca in agriculture.
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