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Title:Organoapatites: New materials for artificial bone
Author(s):Ciegler, Glenn Warren
Doctoral Committee Chair(s):Stupp, Samuel I.
Department / Program:Materials Science and Engineering
Discipline:Materials Science and Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Chemistry, Polymer
Engineering, Biomedical
Engineering, Materials Science
Abstract:New implant materials are necessary in medicine for use in bone fracture repair devices, skeletal replacements, dental restoratives, or bony augmentation surgeries. The materials used in each of these applications require specific properties. Generally speaking, an artificial bone material would be useful wherever autogenous bone grafts are presently required. Specific examples include replacement or reconstruction of congenital or trauma induced hard tissue defects, repair after resection of osseous neoplasms, arthrodesis operations secondary to severe rheumatic diseases or failed joint replacements, and other operative procedures such as craniotomy where replacement bone is needed. Research was initiated to investigate the possibility of producing artificial bone composite materials. Modeled after calcified natural tissues, the microstructure of these materials was composed of hydroxyapatite or its chemical analogs and either synthetic polyelectrolytes or biopolymers. These organoapatites were synthesized in a special reaction chamber and products were collected by centrifugation of reaction solutions. The precipitation of calcium-phosphate products occurred in the presence of various polyelectrolytes, namely, poly(acrylic acid), poly(dimethyl diallyl ammonium chloride), or either of two biopolymers, poly(sodium glutamate) or poly(lysine hydrochloride). Physico-chemical characterization of the organoapatites included infrared and ultraviolet spectroscopy, wide angle X-ray powder diffraction, Scanning Electron Microscopy, B.E.T. surface area determination with pore-size distribution, and elemental composition. Biological studies of these new materials involved surgical implantation of preformed cylindrical implants into tibial cortices in the adult canine model and subsequent analysis of in situ and retrieved specimens by histopathology, histomorphometrics and Roentgenography. The results indicated that control over the organoapatites physical and chemical properties such as crystallinity, surface-area and elemental content ratio could be achieved with variation in concentration and degree of ionization of added polyelectrolyte. The biological experiments indicate that the presence of polyelectrolyte during the precipitation and maturation of our calcium phosphates significantly altered the in vivo properties of our materials relative to control pure-mineral implants. Specifically, implant integrity was much improved with the minute addition of biopolymers during the precipitation without significant loss of biocompatibility seen in the polyacrylate organoapatite. The biopolymeric organoapatites were well accepted by the bony tissue environment with remarkably good bone to implant contact observed in histological analyses.
Issue Date:1989
Rights Information:Copyright 1989 Ciegler, Glenn Warren
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI8924793
OCLC Identifier:(UMI)AAI8924793

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