Bioactive glass – in search of synthetic alternatives | Gdańsk University of Technology

The materials currently used for bone implants production are composed of bioactive glass.  It is commonly used silicate-based glass, which is added even to some toothpastes. Thanks to them, implants have properties that force the bone to regenerate exactly in the place where they are located. Silicon oxide constitutes 50% of the composition of this glass, the rest being admixtures of phosphorus, calcium and sodium oxide.

– The silicate-based glass used now, dissolve very slowly – says the researcher – If we place this material where the defect is, it is intended to stimulate the bone to produce hydroxyapatite, the main building block of the bone, and thereby regenerate, gradually dissolving itself. Classic bioglass with a high silicon content, however, dissolves too slowly –  from one year to even several years. The problem is that silicon is an element that occurs naturally in the human body only in trace amounts. We do not know the long-term consequences of this element remaining in the body in high concentration.

Replacing the main silicate matrix in bioglass production with a phosphate matrix results in a considerable increase in the solubility of the material, because such are the properties of phosphates. Moreover, phosphorus occurs in living organisms and is a natural building block of bones, so dissolving it will not be a burden, as in the case of silicon. Natalia Wójcik is working on phosphate-based materials that will achieve optimal dissolution properties for a given bone defect.

–  Simply speaking, the implant must dissolve slowly enough for the bone to regenerate and fast enough not to interfere with the last stage of regeneration.

The composition of the bioglass produced and tested by the researcher, apart from phosphorus, includes calcium and sodium, as well as niobium and nitrogen. Adding a small amount of nitrogen does not have negative effects on the body, however it affects the solubility. Niobium, on the other hand, improves the bioactive properties of the material and also affects the solubility.

In the following stage, doctor Wójcik extended her in vitro research of the solubility of bioactive glass to magnesium and aluminum. So far, she has published four articles on this topic. She conducts her research in cooperation with research centers from Sweden, Finland and Saudi Arabia and with the support of Stefania Wolff, Eng.

The target result of the research would be a composite that can be used to produce advanced implants that fill mini cavities in bones, which will accelerate bone regeneration or serve as a coating for permanent implants, e.g. titanium.

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The project titled “Niobium and nitrogen containing bioactive glasses and glass-ceramics for bone-implant applications” is carried out as part of the program Argentum Triggering Research Grants.

Funds granted: PLN 273 430

Project implemented within Advanced Materials Center