Antibacterial and antioxidant electrospun materials from poly(3-hydroxybutyrate) and polyvinylpyrrolidone containing caffeic acid phenethyl ester - "in" and "on" strategies for enhanced solubility.

Caffeic acid phenethyl ester (CAPE) possesses a set of valuable biological properties: antioxidant, antibacterial, antitumor, anti-inflammatory, antiviral, etc. However, CAPE is poorly soluble in aqueous environment which is limiting its possible therapeutic applications. In the present study novel fibrous materials enhancing CAPE solubility and accelerating CAPE release were developed. The materials were prepared from poly(3-hydroxybutyrate) (PHB) by electrospinning and by electrospinning combined with dip-coating. The effects of the composition - without/with addition of polyvinylpyrrolidone (PVP) and of the design of fiber (CAPE in the bulk of the fiber or incorporated in the PVP coating) on some of the properties of these materials were studied. X-ray diffraction and differential scanning calorimetry analyses revealed that CAPE was in the amorphous state in CAPE-loaded fibers and in the PVP coating. The new CAPE-containing materials exhibited good antioxidant activity. The microbiological screening demonstrated that incorporation of CAPE in the fibers or in the coating induced complete killing of Gram-positive S. aureus and led to inhibition of the growth of Gram-negative E. coli by the fibrous materials. Moreover, pathogenic S. aureus did not adhere onto CAPE-containing fibrous mats. Therefore, the obtained materials are promising candidates for use as wound dressing materials.