Figures & data
Figure 1 Characterization of HAP sol.
Notes: (A) Photograph of HAP precursor sol, (B) TEM micrograph of HAP nanoparticles.
Abbreviations: HAP, hydroxyapatite; TEM, transmission electron microscopy.
![Figure 1 Characterization of HAP sol.Notes: (A) Photograph of HAP precursor sol, (B) TEM micrograph of HAP nanoparticles.Abbreviations: HAP, hydroxyapatite; TEM, transmission electron microscopy.](/cms/asset/84815eac-df79-449a-a703-4286440448dc/dijn_a_79241_f0001_b.jpg)
Figure 2 XRD pattern of HAP particles in sol.
Abbreviations: HAP, hydroxyapatite; XRD, X-ray diffraction.
![Figure 2 XRD pattern of HAP particles in sol.Abbreviations: HAP, hydroxyapatite; XRD, X-ray diffraction.](/cms/asset/968b5044-32fb-4fee-bab1-56e11f1a9176/dijn_a_79241_f0002_c.jpg)
Figure 3 The morphology of electrospun fibers with different HAP contents.
Notes: (A) 0%, (B) 10%, (C) 20%, (D) 30%, (E) 40%, and collagen/30% HAP control fibers (F), respectively.
Abbreviation: HAP, hydroxyapatite.
![Figure 3 The morphology of electrospun fibers with different HAP contents.Notes: (A) 0%, (B) 10%, (C) 20%, (D) 30%, (E) 40%, and collagen/30% HAP control fibers (F), respectively.Abbreviation: HAP, hydroxyapatite.](/cms/asset/1cdb8c8b-5615-4c91-816f-9941a0e2e6cb/dijn_a_79241_f0003_c.jpg)
Figure 4 TEM images of the fibers and spinning solutions.
Notes: (A) Collagen fibers before desalination, (B) collagen/HAP before desalination, (C) collagen fibers after desalination, (D) collagen/HAP after desalination, (E) collagen/30% HAP spinning solution, (F) collagen/30% HAP fibers after desalination, (G) collagen/HAP spinning solution using HAP powders, (H) collagen/30% HAP control fibers.
Abbreviations: HAP, hydroxyapatite; TEM, transmission electron microscopy.
![Figure 4 TEM images of the fibers and spinning solutions.Notes: (A) Collagen fibers before desalination, (B) collagen/HAP before desalination, (C) collagen fibers after desalination, (D) collagen/HAP after desalination, (E) collagen/30% HAP spinning solution, (F) collagen/30% HAP fibers after desalination, (G) collagen/HAP spinning solution using HAP powders, (H) collagen/30% HAP control fibers.Abbreviations: HAP, hydroxyapatite; TEM, transmission electron microscopy.](/cms/asset/ae3c7d5e-93f3-4bb6-845a-c62af5641dc1/dijn_a_79241_f0004_b.jpg)
Figure 5 Schematic illustration of the proposed mechanism for the HAP particles oriented along the long axes of the collagen fiber.
Abbreviation: HAP, hydroxyapatite.
![Figure 5 Schematic illustration of the proposed mechanism for the HAP particles oriented along the long axes of the collagen fiber.Abbreviation: HAP, hydroxyapatite.](/cms/asset/8e9f24f5-3ce2-4d4d-a67e-322eed44e3ce/dijn_a_79241_f0005_c.jpg)
Figure 6 FTIR spectra.
Notes: (A) HAP, (B) collagen fibers, (C) collagen/HAP composite fibers.
Abbreviations: HAP, hydroxyapatite; FTIR, Fourier-transform infrared spectroscopy; au, arbitrary units.
![Figure 6 FTIR spectra.Notes: (A) HAP, (B) collagen fibers, (C) collagen/HAP composite fibers.Abbreviations: HAP, hydroxyapatite; FTIR, Fourier-transform infrared spectroscopy; au, arbitrary units.](/cms/asset/7d6170b3-580a-4b69-a597-803746f9007f/dijn_a_79241_f0006_c.jpg)
Figure 7 XRD patterns of collagen fibers and collagen/HAP fibers.
Notes: (A) Collagen fibers before desalination, (B) collagen fibers after desalination, (C) collagen/30% HAP composite fibers.
Abbreviations: HAP, hydroxyapatite; XRD, X-ray diffraction.
![Figure 7 XRD patterns of collagen fibers and collagen/HAP fibers.Notes: (A) Collagen fibers before desalination, (B) collagen fibers after desalination, (C) collagen/30% HAP composite fibers.Abbreviations: HAP, hydroxyapatite; XRD, X-ray diffraction.](/cms/asset/a1192831-404b-4d90-b884-ff5bef9c2f0a/dijn_a_79241_f0007_c.jpg)
Figure 8 SEM photographs of the electrospun fibers after cross-linking with EDC/NHS.
Notes: (A) Collagen fibers, (B) collagen/10% HAP fibers, (C) collagen/30% HAP fibers.
Abbreviations: HAP, hydroxyapatite; SEM, scanning electron microscope; EDC/NHS, 1-ethyl-3-(3-dimethyl-aminopropyl)-1-carbodiimide hydrochloride/N-hydroxysuccinimide.
![Figure 8 SEM photographs of the electrospun fibers after cross-linking with EDC/NHS.Notes: (A) Collagen fibers, (B) collagen/10% HAP fibers, (C) collagen/30% HAP fibers.Abbreviations: HAP, hydroxyapatite; SEM, scanning electron microscope; EDC/NHS, 1-ethyl-3-(3-dimethyl-aminopropyl)-1-carbodiimide hydrochloride/N-hydroxysuccinimide.](/cms/asset/f4f7a155-2433-45e9-82af-df4e00f5b4a6/dijn_a_79241_f0008_b.jpg)
Table 1 Mechanical properties of collagen and collagen/HAP composite fibers with different content of HAP