Fabrication, Physicochemical Characterization, and in Silico Evaluation of Bilayer Nanofibers as a Potential Sustained Crocin Delivery Dressing

This research aimed to produce zein-based bilayer nanofibers to sustain the release of crocin. Zein and gelatin were blended to form the drug-eluting layer, while polycaprolactone (PCL) was used to fabricate the backing layer.

Bilayer nanofibers were fabricated through sequential electrospinning. For fabricating the drug-eluting layer, zein solutions at the concentrations of 30% and 40% w/v were prepared and blended with gelatin solution (20% w/v) at four zein/gelatin solution mass ratios. After finding the optimized solution, PCL (12% w/v) was electrospun on the drug-eluting layer. The prepared nanofibers were characterized regarding morphology, FTIR, XRD, water contact angle, swelling, in vitro release, and mechanical properties. Molecular docking studies were also used to demonstrate interactions in crocin-zein and crocin-gelatin complexes.

SEM micrographs showed that the ideal nanofibers consisted of zein 40% w/v and gelatin 20% w/v with a zein/gelatin solution mass ratio of 80:20. These nanofibers had an average diameter of ~ 500 nm and showed a good yield in the production process. Solid state characterizations (FTIR and XRD) demonstrated compatibility between crocin and the polymers. The bilayer nanofibers exhibited sustained release of crocin (up to 56.6% in 5 days) by preventing the shrinkage of the zein/gelatin nanofibers. Additionally, the bilayer nanofibers exhibited improved mechanical properties. Computational characterization showed favorable binding energies of -5.9 kcal/mol for the gelatin-crocin complex and -5.6 kcal/mol for the zein-crocin complex.

Based on the findings, it appears that the zein-based bilayer nanofibers could be an effective delivery system for crocin, potentially providing a sustained release for localized applications.