Artificial stabilized composition of calcium phosphate phases particularly adapted for supporting bone cell activity

Abstract

This invention relates to a bioactive artificial sintered composition for providing a morphology capable of consistently supporting bone cell activity thereon. The composition comprises stabilized calcium phosphate phases developed by the conversion of a hydroxyapatite substance in the presence of stabilizing entities at sintering temperatures into insolubilized and stabilized tricalcium phosphate. The present invention has numerous applications in medical diagnostics for the assessment of abnormal bone cell activity as well as for medical therapeutics, including bone and dental tissue replacement and repair as well as for ex vivo bone graft tissue engineering.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. application Ser. No. 09 / 029,872 filed Jun. 29, 1998, which is a U.S. national phase application of PCT / CA96 / 00585, filed Aug. 30, 1996, which is a continuation-in-part of U.S. application Ser. No. 08 / 576,238, filed Dec. 21, 1995, now abandoned, which claims the benefit of U.S. Provisional Application Ser. No. 60 / 003,157, filed Sep. 1, 1995, which are each hereby incorporated herein in their entirety by reference.FIELD OF THE INVENTION [0002] This invention relates to bioactive artificial stabilized sintered compositions of calcium phosphate phases which are capable of supporting bone cell activity thereon. This invention has applications in medical diagnostics for the assessment of normal and abnormal bone cell activity as well as for medical therapeutics including bone and dental tissue replacement and repair as well as for ex vivo bone graft tissue engineering. BACKGROUND OF THE INVENTION [00...

AI Technical Summary

Benefits of technology

[0021] The present invention provides a stabilized composition which provides for a wide variety of diagnostic and therapeutic applications. The stabilized composition, in accordance with an aspect of the invention, can be used to provide a range of thin films, coatings, powders and bulk ceramic pieces which share a common surface globular microporisity and an internal microporosity. In addition, the bulk ceramics also can have a macroporosity within the structure in order to provide an artificial three dimensional bone tissue similar to that found in vivo. The composition, made in any form, encourages the activity of bone cells cultured thereon and also allows for the development of ex vivo engineered artificial bone tissues to use as bone grafts.

[0023] According to another aspect of the present invention is a process for stabilizing an artificial sintered composition of calcium phosphate phases having a morphology suitable for supporting bone cell activity thereon, the process comprising converting an hydroxyapatite substance, into primarily alpha tricalcium phosphate by sintering, and providing stabilizing entities which stabilize and insolubilize the formed alpha tricalcium phosphate within the phosphate phases.

[0027] b) a layer of stabilized calcium phosphate phases developed by the conversion of a hydroxyapatite substance in the presence of stabilizing entities at sintering temperatures into tricalcium phosphate where the stabilizing entities insolubilize and stabilize the calcium phosphate phases;

Problems solved by technology

In addition these analysis techniques are also very time consuming and require highly specialized equipment and training.

Furthermore, the preparation and subsequent examination of bone or dentine slices is neither an easy nor practical method for the assessment of osteoclast activity.

The use of artificial calcium phosphate preparations as substrata for osteoclast cultures has also met with little success.

These results would indicate that functional osteoclasts are difficult to culture in vitro.

Although these different compositions may be used as biocompatible coatings for implants and the like, none of these compositions have been demonstrated to be suitable for the culture of both active osteoclasts and osteoblasts in a reliable and reproducible manner such to allow for the quantitative assessment of the specific activity of osteoclast resorption and osteoblast secretion of bone matrix.

Furthermore, none of the prior compositions developed, can be manipulated to reliably produce a range of films, thicker coatings and bulk ceramic pieces which share a common composition and morphology which leads to similar bioactive performance in vivo and in vitro.

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