Scheme 1. Schematic illustration of the preparation of SNP-PB / COLI incorporated CSPVA electrospun nanofibers, and the mechanism in applications for wound healing.

Fig. 1. (A) FTIR spectra of PVP, Potassium ferricyanide, Sodium nitroprusside and SNP-PB NPs. (B) TEM images of SNP-PB NPs. (C) EDX mapping (scale bar = 150 nm) images of C, Fe, N, O of SNP-PB NPs. (D) UV-vis-NIR spectra of SNP-PB NPs. (E) Hydrodynamic diameter of SNP-PB NPs.

Fig. 2. (A) Photothermal curves of different concentration of SNP-PB NPs irradiated for 6 min. (B) The thermal imager recorded after irradiated for 6 min. (C) Photothermal curves of different concentration of SNP-PB nanofibrous scaffold irradiated for 6 min. (D) Temperature changes of SNP-PB nanofibrous scaffold after repeated exposure to 808 nm laser (all at 0.5 W/cm2). (E) NO release profiles of SNP-PB NPs (1 mg/mL) after irradiated with NIR at power of 0, 0.5, 1.0, and 1.5 W/cm2. (F) NIR controllability of NO release for SNP-PB NPs (1 mg/mL) indicated under 808 nm laser (0.75 W/ cm2).

Fig. 3. SEM images (A), EDX analysis (B) of the SNP-PB/COLI incorporated CSPVA nanofibers. TEM images of CSPVA (C) and SNP-PB/COLI incorporated CSPVA nanofibers (D).

Fig. 4. (A) Viability (%) of L929 cells at different concentration incubated with the nanofibers scaffold (*p<0.05 compared with control). (B) Hemolysis test of the nanofibers scaffold. (C) Microscope images of calcein AM (green, live cells) and PI (red, dead cells) costained L929 cells treated with SNP-PB nanofibrous scaffold. (Scale bar = 200 µm.)

Fig. 5. Photographs of bacterial colonies formed by S. aureus (A) and E. coli (C) treated with different concentration of nanofibrous scaffold without or with 808 nm laser irradiation (1.0 W/cm2, 5 min). The corresponding bacterial viabilities of S. aureus (B) and E. coli (D) measured using plate count method.

Fig. 6. Photographs of bacterial colonies formed by S. aureus (A) and E. coli (C) treated with different nanofibrous scaffold with or without 808 nm laser irradiation (1.0 W/cm2, 5 min). The corresponding bacterial viabilities of S. aureus (B) and E. coli (D) measured using plate count method.

Fig. 7. Flurescence images of S. aureus (A) and E. coli (B) incubated with PBS, SNP-PB nanofibrous+ice, PB nanofibrous and SNP-PB nanofibrous by SYTO-9 and PI costained.

Fig. 8. (A) Visual observation of healing process upon S. aureus infected wounds treated with PBS (control), NIR (1.0 W/cm2, 5 min) alone, nanofibrous scaffold alone, nanofibrous scaffold + NIR (1.0 W/ cm2, 5 min). (B) Graphical representation of quantitative measurement of wound area on the1th, 5th, 10th days.

Fig. 9. H&E and Masson’s trichrome staining images of the wound tissues of four experimental groups on the 5th and 10th days in the wound-healing process, respectively. Black arrow, red arrow, black dash circle, red dash circle, black dash line indicated inflammatory cells, hair follicles, damaged epidermis, damaged dermis, and boundary of epithelium, respectively. Scale bars are 200 µm.

Fig. 10. Immunohistochemical CD31 images of four experimental groups on the 5th and 10th days. Scale bars are 200 µm.

Fig. 11. H&E staining of the major organs (heart, liver, spleen, lung, and kidney) of mice after different treatments. (Scale bars are 200 µm)