Controlled gentamicin release from multi-layered electrospun nanofibrous structures of various thicknesses

Figures & data

Table 1 Morphological characteristics of the prepared nanofibers

Polymer	Basis weight (g/m^2)a	Layer thickness (μm)a	Surface area (m^2/g)b	Porosity (%)b
PVAc	0.8	3.1 ± 0.6	12.8	85.8
PUR	1.5	3.4 ± 1.0	7.5	78.9
PUR	4.4	8.1 ± 1.1	9.1	76.8
PUR	14.7	26.3 ± 3.7	8.5	70.7

Notes:

a Measured on multilayered structures of PUR/PVA/PUR mats;

b measured on single PVA and PUR layers;

c the PVA layer was thermally crosslinked.

Abbreviations: PUR, polyurethane; PVA, polyvinyl alcohol.

Figure 1 SEM images of multilayer nanofibrous structures in which the middle crosslinked PVA layer (0.8 g/m²) containing 10 wt% gentamicin is covered with PUR layers of 1.5 (A), 4.4 (B), or 14.7 g/m² (C) basis weight.

Abbreviations: PUR, polyurethane; PVA, polyvinyl alcohol; SEM, scanning electron microscopy.

Figure 2 The areas of inhibited growth of Staphylococcus aureus (A–C) and Pseudomonas aeruginosa (D–F) around gentamicin standard discs (A and D), a noncrosslinked PVA layer with 10 wt% gentamicin (B and E), and a crosslinked PVA layer with 10 wt% gentamicin (C and F).

Note: Scale: 1 cm.

Abbreviation: PVA, polyvinyl alcohol.

Figure 3 Release profiles of gentamicin into water from PUR/PVA/PUR nanofibrous sandwiches with PUR layers of 1.5, 4.4, or 14.7 g/m² basis weight and a noncrosslinked (A) or crosslinked (B) PVA layer.

Abbreviations: PUR, polyurethane; PVA, polyvinyl alcohol.

Figure 4 Release profiles of gentamicin to agar from PUR/PVA/PUR nanofibrous sandwiches with crosslinked PVA layers and PUR layers of 1.5, 4.4, or 14.7 g/m² basis weights, expressed as the percentage of residual gentamicin remaining in the nanofibrous discs.

Abbreviations: PUR, polyurethane; PVA, polyvinyl alcohol.

Figure 5 (A) Area of inhibition (% of the maximal inhibition area after 48 hours) of Staphylococcus aureus agar cultures around nanofibrous samples during gentamicin release. (B) Inhibitory zones from the residual gentamicin in the nanofibrous samples after various intervals of gentamicin release.