Zinc-Loaded PVA/Zein Nanofibers Applied as Seed Coating.

The development of a seed coating with micronutrient release system is of extreme research importance for sustainable agriculture. In this work, a zinc release system was developed, using zinc-loaded PVA/Zein nanofibers. Solution blow spinning was used to produce nanofibers (average diameter of approximately 160 nm), as demonstrated by field-emission scanning electron microscopy (FE-SEM), with some bead presence, which served as main zinc reservoir, as evidenced by energy-dispersive X-ray spectroscopy (EDX). Biodegradation assay showed the biodegradability of the PVA/Zein nanofibers with over 30% mass loss after 31 days, an important and desired ability for the proposed application. Encapsulation efficiency of the nanofibers was measured at more than 90%. The release profile of zinc-loaded nanofibers was observed to be a two-step release, with an initial burst release (approximately 52% in 3 h) followed by a slow release (approximately 6% in 189 h), which is related to the zinc reservoir in the nanofibers that was observed by EDX and is a profile that is advantageous for the proposed application. Germination assay shows that the seed coating applied to the soybean seeds was effective, with the zinc released from the nanofibers being absorbed by the seeds and, acting as fertilizer, improved some of the analyzed parameters (approximately 24, 59 and 127% increase in shoot length, α-chlorophyll and zinc content, respectively). Results demonstrated that zinc-loaded PVA/Zein nanofibers are a promising material for to be used as seed coating, being able to improve crop performance. [ABSTRACT FROM AUTHOR]