*2.8. Quantification of Inflammatory Cytokine*

The effect of the PVDF composite nanofibers on the expression of the inflammatory cytokine interleukin-6 (IL-6) was measured using the RAW 264.7 cells. For the quantification of IL-6 production, the cells (2 × <sup>10</sup><sup>4</sup> cells/well) were precultured in Dulbecco's modified Eagle's medium (DMEM) containing 10% heat-inactivated FBS, 100 U/mL of penicillin, and 100 μg/mL of streptomycin for 24 h at 37 ◦C before adding 1 μg/mL of LPS into the cell culture plate. After activation of the cells for 24 h, the amount of IL-6 released into the media was measured by mouse IL-6 enzyme-linked immunosorbent assay kit (R&D Systems, USA) according to the manufacturer's protocol.

### *2.9. Statistical Analysis*

All data were represented as mean value ± standard deviation. Differences between two groups were analyzed with a one-way ANOVA followed by a Turkey test using SigmaPlot 13.0 (Systat Software, CA). A significant difference was defined for values of *p*\* < 0.05.
