Electrospun Eco-Friendly Materials Based on Poly(3-hydroxybutyrate) (PHB) and TiO2with Antifungal Activity Prospective for Esca Treatment

Esca is a type of grapevine trunk disease that severely affects vine yield and longevity.Phaeomoniella chlamydospora(P. chlamydospora) 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 againstP. chlamydosporabased on biodegradable and biocompatible poly(3-hydroxybutyrate) (PHB), nanosized TiO2-anatase (nanoTiO(2)), and chitosan oligomers (COS) by conjunction of electrospinning and electrospraying. One-pot electrospinning of a suspension of nanosized TiO(2)nanoparticles in PHB solution resulted in materials in which TiO(2)was incorporated within the fibers (design type in). Simultaneous electrospinning of PHB solution and electrospraying of the dispersion of nanosized TiO(2)in COS solution enabled the preparation of materials consisting of PHB fibers on which TiO(2)was deposited on the fibers' surface (design type on). 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(2)in the PHB fibers, as well as nanoTiO(2)deposition onto the surface of the PHB fibers resulted in increased roughness and hydrophobicity of the obtained composite fibrous materials. Moreover, TiO2-on-PHB fibrous material exhibited complete inhibition of fungal growth ofP. chlamydospora. Therefore, the obtained eco-friendly fibrous materials based on PHB and nanoTiO(2)are promising candidates for protection against esca in agriculture.