Wollastonite nanofiber–doped self-setting calcium phosphate bioactive cement for bone tissue regeneration

Figures & data

Table 1 Effects of wollastonite nanofiber (WNF) amounts on properties of WNF-doped calcium phosphate cement (CPC) (powder-to-liquid ratio, 2.5)

WNF amount (wt%)	Setting time (minutes)	Compressive strength (MPa)	Contact angle (degrees)
0 (ie, undoped CPC)	8.2 ± 0.2	45.0 ± 2.6	61.6 ± 0.2
5	9.2 ± 0.2	43.7 ± 1.6	34.5 ± 0.3
10	10.5 ± 0.4	42.3 ± 2.1	15.7 ± 0.9
15	21.5 ± 0.4	37.4 ± 1.8	0
20	44.8 ± 1.3	32.1 ± 2.2	0

Note: Data presented as mean plus or minus standard deviation.

Table 2 Effects of powder-to-liquid (P/L) ratio on properties of wollastonite nanofiber (WNF)–doped calcium phosphate cement with 10 wt% WNFs

P/L ratio (g mL^−1)	Setting time (minutes)	Compressive strength (MPa)
3	8.3 ± 0.2	38.0 ± 2.5
2.5	10.5 ± 0.4	42.3 ± 2.1
2	15.8 ± 0.5	37.3 ± 2.2
1.5	36.3 ± 1.2	29.6 ± 4.6
1	56.0 ± 2.2	19.2 ± 5.8

Note: Data presented as mean plus or minus standard deviation.

Figure 1 Scanning electron microscope images of wollastonite nanofibers with different magnifications: (A) ×30000 and (B) ×60000.

Figure 2 X-ray diffraction (A) and Fourier transform infrared spectroscopy (B) patterns of wollastonite nanofibers (WNFs), WNF-doped calcium phosphate cement (wnf-CPC) with 10 wt% WNFs, and calcium phosphate cement (CPC).

Abbreviation: HA, hydroxyapatite.

Figure 3 Scanning electron microscope images of surface morphology/microstructure of (A) wollastonite nanofiber–doped calcium phosphate cement with 10 wt% wollastonite nanofibers and (B) calcium phosphate cement.

Figure 4 Weight loss ratio of wollastonite nanofiber (WNF)–doped calcium phosphate cement (wnf-CPC) and calcium phosphate cement (CPC) soaking in tris hydrochloride solution over time.

Figure 5 Changes in calcium (Ca), silicon (Si), and phosphorus (P) ion concentrations in the tris hydrochloride solution for wollastonite nanofiber–doped calcium phosphate cement with 10 wt% wollastonite nanofibers over time.

Table 3 Effects of soaking time on porosity of calcium phosphate cement (CPC) and wollastonite nanofiber–doped CPC (wnf-CPC) with 10 wt% wollastonite nanofibers (powder-to-liquid ratio, 2.5)

Soaking time (weeks)	Porosity (%)
	wnf-CPC	CPC
1	27.4 ± 2.7	6.7 ± 1.2
4	34.3 ± 3.2	8.4 ± 1.4
8	43.5 ± 2.6	9.3 ± 1.0
12	55.7 ± 2.4	11.3 ± 1.6

Note: Data presented as mean plus or minus standard deviation.

Figure 6 Scanning electron microscope images of surface morphology of (A) wollastonite nanofiber–doped calcium phosphate cement with 10 wt% wollastonite nanofibers and (B) calcium phosphate cement immersed in tris hydrochloride solution for 5 weeks.

Figure 7 Methyl-thiazolyl-tetrazolium bromide assay of attachment ratio of MG-63 cells on wollastonite nanofiber (WNF)–doped calcium phosphate cement (wnf-CPC) with 10 wt% WNFs, calcium phosphate cement (CPC), and a tissue culture plate as a control after being cultured for 4 hours.

Abbreviation: OD, optical density.

Figure 8 Methyl-thiazolyl-tetrazolium bromide assay of proliferation of MG-63 cells on wollastonite nanofiber (WNF)–doped calcium phosphate cement (wnf-CPC) with 10 wt% WNFs, calcium phosphate cement (CPC), and a tissue culture plate as a control at different times.

Abbreviation: OD, optical density.

Figure 9 Morphology of cells cultured with samples for 3 days: (A) wollastonite nanofiber–doped calcium phosphate cement with 10 wt% wollastonite nanofibers and (B) calcium phosphate cement.

Notes: M represents materials; C represents cells; arrow indicates interface between materials and cells.

Figure 10 Scanning electron microscope images of MG-63 cells spread on (A) wollastonite nanofiber–doped calcium phosphate cement with 10 wt% wollastonite nanofibers and on (B) calcium phosphate cement samples for 3 days.

Note: Arrow indicates cells.

Table 4 Changes in calcium (Ca), silicon (Si), and phosphorus (P) concentrations and pH values in culture medium with time

Time (days)	Concentration (ppm)						pH value
	Ca		Si		P		wnf-CPC	CPC
	wnf-CPC	CPC	wnf-CPC	CPC	wnf-CPC	CPC
0	75.6	75.6	NA	NA	34.2	34.2	7.4	7.4
1	96.4	88.3	28.6	NA	44.5	41.7	7.7	7.2
4	120.8	103.1	46.1	NA	55.5	47.3	7.5	7.0
7	149.2	111.9	55.2	NA	60.4	50.8	7.5	7.0

Abbreviations: CPC, calcium phosphate cement; wnf-CPC, wollastonite nanofiber– doped calcium phosphate cement.

Figure 11 Hematoxylin and eosin–stained sections (magnification, ×20) of wollastonite nanofiber–doped calcium phosphate cement with 10 wt% wollastonite nanofiber samples implanted into bone defects of rabbit femora for (A) 3, (B) 6, and (C) 12 weeks, and of (D) calcium phosphate cement implanted for 12 weeks.

Notes: B represents new bone tissues; M represents implanted materials.

Figure 12 Histomorphometric analysis of bone defects repaired by wollastonite nanofiber–doped calcium phosphate cement (wnf-CPC) with 10 wt% wollastonite nanofibers and calcium phosphate cement (CPC) over time.

Notes: Data presented as mean plus or minus standard deviation; n = 4.