300 mesh copper grid

The morphology of the electrospun fibers was investigated by scanning electron microscopy (SEM), using a Jeol JSM 6610 (Jeol Ltd., Tokyo, Japan) with an accelerated voltage of 15kV. The samples were sputtered with a gold layer just before analysis. AzTec software Ver. 2.1. (Springfield, NJ, USA) was used for making figures and processing the results. The average diameter and dispersity of diameters were estimated on the basis of SEM images by using the freely accessible online software ImageJ Ver. 1.53e (LOCI, University of Wisconsin, Madison, WI, USA). The fiber diameter is expressed as average diameter ± standard deviation. One hundred fiber segments were analyzed randomly on 3 independently prepared samples to obtain a mean diameter for each type of nonwoven sample.
The measurements of the beads’ dimensions were carried out at the coarsest place on the individual beads. The average diameter was obtained from 50 measurements on 50 different beads.
Transmission electron microscopy (TEM) analysis was carried out with a Hitachi High-Tech HT7700 (Tokyo, Japan) instrument, operated in high contrast mode at 100 kV accelerating voltage. The samples were prepared by sandwiching the filaments between two uncovered 300 mesh copper grids (Ted Pella, Redding, CA, USA).
The proof of mechanical integrity was provided by using the Canon PowerShot SX130 camera (Tokyo, Japan).

The ultrastructure features were evaluated by transmission electron microscopy (TEM). SCC-25 and L929 cells (4.5 × 10⁵ cells/well) were cultured in a 12-well plate for 24 h. Subsequently, they were incubated with a hydrogel solution and with their re-spective controls in full medium (equivalent to 500 µg/mL of dry V. album for SCC-25 and L929 cell lines). After 24 h, treated and untreated cells were centrifuged, the supernatant discarded, and the cells were fixed for 1 h in glutaraldehyde 2.5% containing sodium cacodylate buffer 0.1 M (pH 7.2). Subsequently, the material was washed in the same buffer, post fixed in osmium tetroxide 1% for 1 h, and washed with 0.1 M cacodylate buffer. Finally, all cells were dehydrated in acetone series and the material was embedded in Polybed 812. Ultrathin sectioning was performed on an EM UC6 microtome (Leica Microsystems GmbH, Wetzlar, Germany). Samples were recovered on 300-mesh copper grids (Ted Pella, Inc.), stained with uranyl acetate and lead citrate, and observed on an FEI Morgagni transmission electron microscope (FEI Company, Hillsboro, OR, USA) operating at 80 kV.