Inorganic shaped bodies and methods for their production and use

Abstract

Shaped, preferably porous, inorganic bodies are provided which are prepared from a reactive blend. In accordance with one preferred embodiment, the solution is absorbed into a porous sacrificial substrate such as a cellulose sponge. The solution-saturated substrate is heated and an oxidation-reduction reaction occurs thereby forming an inorganic solid. A shaped, inorganic body is formed in situ. Optional, but preferred additional thermal treatment of the shaped, inorganic body removes the organic substrate, leaving an inorganic body that faithfully mimics the porosity, shape, and other physical characteristics of the organic substrate. Inorganic substrates may also be used to good effect. Large varieties of shaped bodies can be prepared in accordance with other embodiments of the invention and such shapes find wide use in surgery, laboratory and industrial processes and otherwise. The invention also provides chemically and morphologically uniform powders, including those having uniformly small sizes.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. application Ser. No. 10 / 263,399, filed Oct. 2, 2002, which is a continuation-in-part of U.S. application Ser. No. 09 / 999,506, filed Nov. 15, 2001, now pending, which is a continuation of U.S. application Ser. No. 09 / 253,556, filed Feb. 19, 1999, now U.S. Pat. No. 6,383,519, which claims priority to U.S. Provisional Application No. 60 / 117,254, filed Jan. 26, 1999.FIELD OF THE INVENTION [0002] This invention relates to methods for the preparation of porous inorganic shaped bodies especially calcium phosphate-containing shaped bodies; to the bodies thus prepared; and to methods for use thereof. In accordance with certain embodiments of this invention, shaped bodies are provided which are at once, highly porous and uniform in composition. They can be produced in a wide range of geometric configurations through novel, low temperature techniques. The shaped bodies of the invention can be highly and u...

AI Technical Summary

Benefits of technology

[0017] The present invention is directed to new inorganic bodies, especially controllably porous bodies, which can be formed into virtually any geometric shape. The novel preparative methods of the invention utilize redox precipitation chemistry or aqueous solution chemistry, which is described in pending U.S. patent application Ser. No. 08 / 784,439 assigned to the present assignee and, incorporated herein by reference. In accordance with certain preferred embodiments, the redox precipitation chemistry is utilized in conjunction with a sacrificial, porous cellular support, such as an organic foam or sponge, to produce a porous inorganic product which faithfully replicates both the bulk geometric form as well as the macro-, meso-, and microstructure of the precursor organic support. The aqueous solution, because of its unique chemistry, has a high solids equivalent, yet can essentially be imbibed fully into and infiltrate thoroughly the microstructure of the sacrificial organic precursor material. This extent of infiltration allows the structural details and intricacies of the precursor organic foam materials to be reproduced to a degree heretofore unattainable. This great improvement can result in porous, inorganic materials having novel microstructural features and sufficient robustness to be handled as coherent bodies of highly porous solid.

[0023] A major advantage of the restoration is that after polymerization, it has a significant, inherent strength, such that restoration of load-bearing bony sites can be achieved. While immobilization of the effected part will likely still be required, the present invention permits the restoration of many additional bony areas than has been achievable heretofore. Further, since the porous calcium phosphate scaffolding material of the present invention is biocompatible and, indeed, bioactive, osteogenesis can occur. This leads to bone infiltration and replacement of the calcium phosphate matrix with autologous bone tissue.

[0027] The present invention also provides exceptionally fine, uniform powders of inorganic materials. Such powders have uniform morphology, uniform composition and narrow size distribution. They may be attained through the comminution of shaped bodies in accordance with the invention and have wide utility in chemistry, industry, medicine and otherwise.

Problems solved by technology

Early ceramic biomaterials exhibited problems derived from chemical and processing shortcomings that limited stoichiometric control, crystal morphology, surface properties, and, ultimately, reactivity in the body.

These fabrication methods, however, are not without drawbacks which include cracking upon drying the green body and / or upon firing.

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