Scanning Electron Microscopic and Electrophoretic Studies on Clotting Factor Adsorbents
13 March 1976
Accepted 20 March 1976
03 July 2018 (online)
Physical studies carried out on a range of protein and clotting factor adsorbents revealed marked morphological and charge differences. Their appearance in the scanning electron microscope could be used to classify the insoluble precipitates, calcium phosphate, barium sulphate and citrate, as either amorphorous or crystalline.
Surface charge is difficult to define but the present studies on the sparingly-soluble salts, based on calcium and barium, have revealed that they can be subdivided on the basis of the presence or absence of a charge reversal point in the pH-mobility curve. The anion component appeared to determine this characteristic; it was noted that phosphate and citrate ions had a marked effect and gave a biased negative potential at all pH values. We concluded that where a divalent cation is cohabiting with a trivalent anion, the greater potential-determining ability of the latter will dominate the overall charge at the surface of a particle, even below pH7 and the absence of a positive potential gives a monophasic pH-mobility curve.
Differences in both the physical appearance and electrophoretic mobility of the adsorbents studied reflect the wide variation in their chemical composition, especially among the various forms of calcium phosphate which, unlike barium sulphate, can include substituted ions such as hydroxyl, in their crystal lattice. The definition of these characteristics allows their behaviour towards clotting factors to be more easily predicted.
- 1 Bangham A. D, Flemans R, Heard D. H, Seaman G. V. F. 1958; An apparatus for microelectrophoresis of small particles. Nature 182: 642.
- 2 Goddard G. H. 1970. Some physical-chemical studies of stabilized barium sulphate suspension. Ph. D. Thesis, University of London.;
- 3 Hauschka P. V, Lian J. B, Gallop P. M. 1975; Direct identification of the calcium-binding amino acid, γ-carboxyglutamate, in mineralized tissue. Proceedings of the National Academy of Sciences 72: 3925.
- 4 Howell R. M, Deacon S. L. M. 1975; Scanning electron microscopic and electrophoretic observations on barium sulphates used to adsorb clotting factors. Thrombosis et Diathesis Haemorrhagica 33: 256.
- 5 Howell R. M, Dupe R. J. 1972; Observations on factor X activity after adsorption to barium sulphate. Thrombosis et Diathesis Haemorrhagica 28: 306.
- 6 James A. H, Goddard G. H. 1971; A study of barium sulphate preparations used as X-ray opaque media 1. Particle size and particle charge. Pharmaceutica Acta Helvetiae 46: 708.
- 7 Kehin D, Hartree E. F. 1938; On the mechanism of the decomposition of hydrogen peroxide by catalase. Proceedings of the Royal Society B 124: 397.
- 8 Main R. K, Wilkins M. J, Cole L. J. 1959; A modified calcium phosphate for column chromatography of polynucleotides and proteins. Journal of the American Chemical Society 81: 6490.
- 9 Michaelis L. 1931; Der acetat-veronal-puffer. Biochemische Zeitschrift 234: 139.
- 10 Morimoto T. 1964; The electrokinetic potential of sparingly soluble salts. Bulletin of the Chemical Society of Japan 37: 386.
- 11 Radcliffe R, Nemerson Y. 1975; Activation and control of Factor VII by activated Factor X and thrombin. Journal of Biological Chemistry 250: 388.
- 12 Reyerson L. H, Kolthoff I. M, Coad K. 1947; The electrokinetic potentials of precipitates. Journal of Physical and Colloidal Chemistry 51: 321.
- 13 Rosenberg J. S, McKenna P. W, Rosenberg R. D. 1975; Inhibition of human Factor lXa by human antithrombin. Journal of Biological Chemistry 250: 8883.
- 14 Stenflo J, Fernlund P, Egan W, Roepstorff P. 1974; Vitamin K-dependent modifications of glutamic acid residues in prothrombin. Proceedings of the National Academy of Sciences 71: 2730.
- 15 Tiselius A, Hjertén S, Levin Ö. 1956; Protein chromatography on calcium phosphate columns. Archives of Biochemistry and Biophysics 65: 132.
- 16 Tishkoff G. H, Williams L. C, Brown D. M. 1968; Preparation of highly purified prothrombin complex. Journal of Biological Chemistry 243: 4151.
- 17 Tokiwa F, Imamura T. 1969; Electrophoretic mobility studies of colloidal particles in aqueous solutions of various phosphates. Journal of the American Oil Chemists’ Society 46: 280.
- 18 Tomazic B, Nancollas G. H. 1975; The seeded growth of calcium phosphates. Surface characterization and the effect of seed material, Journal of Colloidal and Interfacial Science 50: 451.