In-situ Transformation of Borate Glass and Its Effect on pH of Soaking-liquid

doi:10.15541/jim20150126

Abstract

Abstract:

The Na-Ca-B glass microspheres with composition of 10Na₂O-10CaO-80B₂O₃(wt%) and 19Na₂O-17CaO- 64B₂O₃(wt%) were prepared (denoted by S1 and S2, respectively) by flame spray ball method. The in-situ transformation of the microspheres into hollow hydroxyapatite(HA) and the influence on the pH value of the soaking-liquid were investigated by using pH meter, XRD, SEM, SEM-EDS, FTIR and BET measurements. In addition, the vancomycin was used as model drug to further investigate the sustained-release performance of hollow HA. The results indicate that S1-HA has larger cavity volume and better drug loading performance with 13.5 mg/g and 16.8% for its drug loading amount and efficiency, respectively. S2 microspheres can greatly influence the pH value of the soaking-liquid. Meanwhile, S2-HA present remarkable multilayered structure and better sustained-release performance with the release time of 60 h.

Key words: borate glass, pH value, hollow hydroxyapatite microspheres, drug sustained release

CLC Number:

TQ171

ZHU Kai-Ping, WANG De-Ping, FAN Hong-Yuan, WANG Hui, YAO Ai-Hua, YE Song. In-situ Transformation of Borate Glass and Its Effect on pH of Soaking-liquid[J]. Journal of Inorganic Materials, 2015, 30(10): 1069-1074.

Figures/Tables 10

Fig. 1 Effect on pH of PBS of NCB glass microspheres

Fig. 2 Multiple effect of glass microspheres on pH of PBS (a) S1 microspheres; (b) S2 microspheres

Fig. 3 Effect principle of NCB glass microspheres on pH of soaking liquid

Fig. 4 XRD patterns of hollow HA microspheres heat-treated at different temperatures. (a) S1-HA microspheres; (b) S2-HA microspheres

Fig. 5 Infrared spectra of hollow HA microspheres

Fig. 6 SEM images of NCB glass microspheres before and after reaction. (a) S1 microspheres before reaction; (b) Fractured section of S1-HA microspheres; (c) Fractured section of S2-HA microspheres

Fig. 7 SEM images (a,c) and EDS spectrum (b,d) of the surface of S1-HA microspheres (a, b) and S2-HA microspheres (c, d). Insets in (a, c) show the high magnification images of the surface. The white boxed areas indicate the positions where the EDS spectrum were taken

Table 1 Surface characteristics and pore structure parameters of the sample

Sample	SA/(m²·g^-1)	PV/(cm³·g^-1)	PS/nm	ZP/mV
S1-HA	38.79	0.12	11.44	-4.98
S2-HA	31.17	0.17	28.29	-3.37

Table 2 Performance of drug-loading and drug-release for hollow HA microspheres

Sample	DLA/(mg·g^-1)	DLE/%	CRE/%
S1-HA	13.5±0.5	16.8±0.6	87.3±1.3
S2-HA	10.6±0.3	13.2±0.4	81.9±1.8

Fig. 8 Cumulative drug release curve in PBS of the drug- loaded hollow HA microspheres

References 17

[1]	HUANG WEN-HAI, DAY DE, KITTIRATANAPIBOON KANISA, et al.Kinetics and mechanisms of the conversion of silicate (45S5), borate, and borosilicate glasses to hydroxyapatite in dilute phosphate solutions.Journal of Materials Science: Materials in Medicine, 2006, 17(7): 583-596.
[2]	ZHANG XIN, JIA WEI-TAO, GU YI-FEI, et al.Borate bioglass based drug delivery of teicoplan in for treating osteomyelitis.Journal of Inorganic Materials, 2010, 25(3): 293-298.
[3]	ZHANG XIN, JIA WEI-TAO, HUANG WEN-HAI, et al.Teicoplanin- loaded borate bioactive glass implants for treating chronic bone infection in a rabbit tibia osteomyelitis model.Biomaterials, 2010, 31(22): 5865-5874.
[4]	FU QIANG, RAHAMAN MN, FU HAI-LUO, et al.Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. Preparation and in vitro degradation.Journal of Biomedical Materials Research-Part A, 2011, 95(1): 164-171.
[5]	LIANG WEN, RAHAMAN MN, DAY DE, et al.Bioactive borate glass scaffold for bone tissue engineering.Journal of Non-Crystalline Solids, 2008, 354(15/16): 1690-1696.
[6]	RAHAMAN MN, DAY DE, Bal BS, et al.Bioactive glass in tissue engineering.Acta Biomater., 2011, 7(6): 2355-2373.
[7]	RAHAMAN MN, BROWN RF, DAY DE, et al.Bioactive glasses for non-bearing applications in total joint replacement.Semin Arthroplasty, 2007, 17(3/4): 102-112.
[8]	XU TENG, SU HANG, GANAPATHY SUTHAKAR, et al.Modulation of autophagic activity by extracellular pH.Autophagy, 2011, 7(11): 1316-1322.
[9]	FU HAI-LUO, RAHAMAN MN, BROWN RF, et al.Evaluation of BSA protein release from hollow HA microspheres into PEG hydrogel.Mater. Sci. Eng. C, 2013, 33(4): 2245-2250.
[10]	ZHANG LI-FANG, YANG DE-JUAN, CHEN HE-CHUN, et al.An ionically crosslinked hydrogel containing vancomycin coating on a porous scaffold for drug delivery and cell culture.Int. J. Pharm., 2008, 353(1/2): 74-87.
[11]	FU HAI-LUO, RAHAMAN MN, DAY DE, et al.Hollow hydroxyapatite microspheres as a device for controlled delivery of proteins. J. Mater. Sci. Mater. Med., 2011, 22(3): 579-591.
[12]	JIANG FEI, WANG DE-PING, YE SONG, et al.Strontium-substituted, luminescent and mesoporous hydroxyapatite microspheres for sustained drug release.J. Mater. Sci: Mater. Med., 2014, 25(2): 391-400.
[13]	WANG QING, HUANG WEN-HAI, WANG DE-PING, et al.Preparation of hollow hydroxyapatite microspheres.J. Mater. Sci: Mater. Med., 2006, 17(1): 641-646.
[14]	WANG YIN-CHUN, YAO AI-HUA, HUANG WEN-HAI, et al.In situ fabrication of hollow hydroxyapatite microspheres by phosphate solution immersion.Journal of Crystal Growth, 2011, 327(1): 245-250.
[15]	PAN HAO-BO, ZHAO XIAN-LIANG, ZHANG XIN, et al.Strontium- borate glass: potential biomaterial for bone regeneration.J. R. Soc. Interface, 2010, 7(48): 1025-1031.
[16]	XIAO WEI, FU HAI-LUO, RAHAMAN MN, et al.Hollow hydroxyapatite microspheres: A novel bioactive and osteoconductive carrier for controlled release of bone morphogenetic protein-2 in bone regeneration.Acta Biomaterialia, 2013, 9(9): 8374-8383.
[17]	YAO AI-HUA, XU WEI, AI FAN-RONG, et al.Study on hollow hydroxyapatite microspheres as delivery system for human bone morphogenetic protein.Journal of Inorganic Materials, 2011, 26(9): 974-978.