Silicon addition to hydroxyapatite increases nanoscale electrostatic, van der Waals, and adhesive interactions

• Type: Article in International Scientific Journal
• Date: 2006

Authors

Jennifer Vandiver (Author) Other; Delphine Dean (Author) Other; Nelesh Patel (Author) Other; Claudia Botelho (Author) Other; Serena Best (Author) Other; Jose D Santos (Author) FEUP; Maria A Lopes (Author) FEUP; William Bonfield (Author) Other; Christine Ortiz (Author) Other

Journal

Title: Journal of Biomedical Materials Research - Part A

Vol. 78A No. 2

Pages: 352-363

ISSN: 1549-3296

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 39 Citations

ISI Web of Science

Scopus - 52 Citations

Scientific classification

FOS: Engineering and technology > Environmental biotechnology

CORDIS: Technological sciences > Engineering > Biomaterial engineering ; Technological sciences > Engineering > Biomedical enginnering

Other information

Authenticus ID: P-004-J65

DOI: 10.1002/jbm.a.30737

Abstract (EN): The normal intersurface forces between nanosized probe tips functionalized with COO--terminated alkanethiol self-assembling monolayers and dense, polycrystalline silicon-substituted synthetic hydroxyapatite (SiHA) and phase pure hydroxyapatite (HA) were measured via a nanomechanical technique called chemically specific high-resolution force spectroscopy. A significantly larger van der Waals interaction was observed for the SiHA compared to HA; Hamaker constants (A) were found to be A(SiHA) = 35 +/- 27 zJ and A(HA) = 13 +/- 12 zJ. Using the Derjaguin-Landau-Verwey-Overbeek approximation, which assumes linear additivity of the electrostatic double layer and van der Waals components, and the nonlinear Poisson-Boltzmann surface charge model for electrostatic double-layer forces, the surface charge per unit area, sigma (C/m(2)), was calculated as a function of position for specific nanosized areas within individual grains. SiHA was observed to be more negatively charged than HA with sigma(SiHA) = -0.024 +/- 0.013 C/m(2), two times greater than sigma(HA) = -0-011 +/- 0.006 C/m(2). Additionally, SiHA was found to have increased surface adhesion (0.7 +/- 0.3 nN) compared to HA (0.5 +/- 0.3 nN). The characterization of the nanoscale variations in surface forces of SiHA and HA will enable an improved understanding of the initial stages of bone-biornaterial bonding. (c) 2006 Wiley Periodicals, Inc.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12