A new type of crystalline calcium phosphate has been discovered and analysed in the laboratories of Leibniz University Hannover (LUH). Calcium orthophosphates, a group of biominerals, are a vital part of the human body and can be found in hard mineralised tissue such as bones or teeth. Calcium orthophosphates crystallise in about a dozen different structures, most of which have already been identified in the 18th and 19th century. During the last century of research, no new crystalline calcium phosphates were discovered. In collaboration with researchers from China, Sweden and Australia, a team at the LUH Institute of Inorganic Chemistry has now uncovered a new type of crystalline calcium phosphate. Last week, their findings were published in the renowned open access journal "Nature Communications".
Owing to its structure, the new crystalline calcium phosphate possesses unique properties, which distinguish it from similar calcium phosphates known to date: it is thermodynamically less stable. This means that it can transform itself into other calcium phosphate structures quite quickly. "Because of this property, it could be used in various medical applications or for improving the quality of water", explains Prof. Dr. Denis Gebauer from the Institute of Inorganic Chemistry.
For example, it could be used as an implant material. Metastable calcium phosphates are currently used as bone cement for attaching implants. Over time, the material is slowly absorbed and replaced by natural bone. Compared to conventional materials, the new mineral has an identical chemical composition. However, it possesses a different structure. For this reason, cured cements obtained from the new mineral could be much more similar to the structure of natural bone than those from conventional formulations, which could be beneficial in terms of structural integration as well as with regard to the body absorbing the cement.
Furthermore, the new crystalline calcium phosphate could be used as a drug carrier. "Due to its metastability, it demonstrates an increased capacity for holding pharmaceutical compounds", illustrates Professor Gebauer: "It facilitates binding of substances that would normally not interact strongly with calcium phosphates, and we were able to demonstrate that the mineral is biologically compatible." In comparison to other known structures, compounds could be introduced into the body more easily.
Finally, the mineral could be used in water treatment. Due to its structural properties, the new and safe calcium phosphate could bind toxic substances in water more efficiently than currently used methods.
Moreover, the new mineral is expected to help researchers to gain a better understanding of certain diseases by providing new insights into the crystallisation mechanisms of calcium orthophosphates. This could enable conclusions to be drawn on the mechanisms of the early stages of arteriosclerosis, as well as the development of kidney and bladder stones or pathological mineralisation of muscle tissue in order to intervene during the intermediate stages of the diseases.
The project that resulted in the discovery of the new calcium phosphate structure was conducted in collaboration with researchers from Shanghai Jiao Tong University Affiliated Sixth People''s Hospital (Shanghai, China), State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics (China), as well as Stockholm University (Sweden) and Curtin University (Perth, Australia).
Note to editors:
For further information, please contact Prof. Dr. Denis Gebauer (Institute of Inorganic Chemistry) at gebauer@acc.uni-hannover.de.
