Calcium Phosphate Nucleation on Surface-Modified PTFE Membranes

Grondahl, Lisbeth, Cardona, Francisco, Chiem, Khang, Wentrup-Byrne, Edeline, & Bostrom, Thor E. (2003) Calcium Phosphate Nucleation on Surface-Modified PTFE Membranes. Journal of Materials Science: Materials in Medicine, 14(6), pp. 503-510.

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Highly porous PTFE membranes are currently being used in facial reconstructive surgery. The present study aims at improving this biomaterial through creating a more bioactive surface by introducing ionic groups onto the surface. The unmodified PTFE membrane does not induce inorganic growth after immersion in simulated body fluid (SBF) for up to 4 weeks. Copolymeric grafting with acrylic acid (AAc) by means of gamma irradiation and subsequent in vitro testing in SBF reveals that this copolymer initially acts as an ion-exchange material and subsequently induces growth of a calcium phosphate phase (Ca/P = 2.7) when large amounts (15%) of pAAc are introduced onto the membrane surface. This copolymer is not expected to function well from a biomaterials perspective since SEM showed the pores on the surface to be partly blocked. In contrast, the surface of monoacryloxyethyl phosphate (MAEP) modified samples is altered at a molecular level only. Yet the modified materials are able to induce calcium phosphate nucleation when the external surface coverage is 44% or above. The initial inorganic growth on these membranes in SBF has a (Ca+Mg)/P ratio of 1.1 (presumably Brushite or Monetite). The secondary growth, possibly calcium-deficient apatite or tricalcium phosphate, has a (Ca+Mg)/P ratio of 1.5. This result is a promising indicator of a bioactive biomaterial.

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ID Code: 3586
Item Type: Journal Article
Refereed: Yes
Keywords: Poly(tetrafluoroethylene), Radiation, induced grafting Simulated body fluid FTIR spectroscopy XPS spectroscopy Electron Microscopy
DOI: 10.1023/A:1023403929496
ISSN: 1573-4838
Divisions: Past > QUT Faculties & Divisions > Faculty of Science and Technology
Copyright Owner: Copyright 2003 Springer
Copyright Statement: The original publication is available at SpringerLink
Deposited On: 23 Feb 2006 00:00
Last Modified: 29 Feb 2012 13:00

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