The Adsorption of Polyelectrolytes on Hydroxyapatite Crystals

Author: Tsortos A.   Nancollas G.H.  

Publisher: Academic Press

ISSN: 0021-9797

Source: Journal of Colloid and Interface Science, Vol.209, Iss.1, 1999-01, pp. : 109-115

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Abstract

The adsorption of two polyelectrolytes, poly-L-Glutamate and poly-L-Aspartate, on hydroxyapatite (HAP) crystals was studied both experimentally and theoretically. Langmuir adsorption isotherms were obtained for both these molecules, with binding constantsK= 6 × 106and 3 × 106M-1, respectively, at 37.0°C, pH 7.4, and 0.15 M ionic strength. A theoretical analysis of the data, based on a model proposed by Hesselink, suggested a “train-loop” type of adsorption with non-electrostatic energy terms 3.51 and 4.76 (kT) for poly-L-Glu and poly-L-Asp, respectively.