Surface Charge of Bioactive Polyethylene Modified with –SO₃H Groups and Its Apatite Inducing Capability in Simulated Body Fluid

Abstract:

A bioactive polyethylene polymer substrate can be produced by incorporation of sulfonic functional groups (-SO3H ) on its surface. Variation of the surface potential of the polyethylene modified with -SO3H groups with soaking in SBF were investigated using a laser electrophoresis zeta-potential analyzer. To complement the study using the laser electrophoresis, the surface was examined by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy with an attached energy dispersive electron probe X-ray analyser (FE-SEM/EDS). It was found that the surface potential of the polyethylene was highly negative charged after soaking in SBF for 0.5 h, increased for higher soaking times (up to 48 h), and then decreased. The negative charge of the polymer at soaking time of 0.5 h is attributed to the presence of –SO3H groups on the surface. The initial increase in the surface potential was attributed to the incorporation of positively charged calcium ions to form a calcium sulphate, and then the subsequent decrease was assigned to the incorporation of negatively charged phosphate ions to form an amorphous calcium phosphate, which eventually transformed into apatite.

• Periodical: Key Engineering Materials (Volumes 284-286)
• Pages: 453-456
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.284-286.453
• Online since: April 2005
• Authors: Isabel B. Leonor, Hyun Min Kim, Francisco Balas, Kawashita Masakazu, Rui L. Reis, Takashi Nakamura
• Keywords: Apatite Structure, Polymer, Simulated Body Fluid (SBF), Sulfonic Group (SO₃H), Zeta-Potential

References

[1] T. Kokubo, H-M. Kim, M. Kawashita: Biomaterials 24 (2003), p.2161.

[2] I. B. Leonor, H. -M. Kim, F. Balas, M. Kawashita, R. L. Reis, T. Kokubo, T. Nakamura: J Biomed Mater Res (2004) submitted.

[3] I. B. Leonor, F. Balas, H. -M. Kim, T. Kokubo, R.L. Reis (2003), 29th Ann. Meet. of Soc. For Biomater., Reno, NV, USA, 387.

[4] T. Kokubo, H. Kushitani, S. Sakka, T. Kitsugi and T. Yamamuro: J Biomed Mater Res 24 (1990), p.721.

DOI: 10.1002/jbm.820240607

h 0, 5 h.

[6] h.

[12] h.

[24] h.

[48] h.

[72] h 168 h Intensity Binding energy / eV.

h 0, 5 h.

[6] h.

[12] h.

[24] h.

[48] h.

[72] h 168 h Intensity Binding energy / eV P2p Ca2p hydroxyapatite hydroxyapatite CaSO4. 2H2O.

h 0, 5 h.

[6] h.

[12] h.

[24] h.

[48] h.

[72] h 168 h Intensity Binding energy / eV O1s P-O Ca-O 545 535 525 515 365 355 345 335 150 140 130 120.