The challenge of bone tissue engineering (BTE) is to develop bone scaffolds that allow a good integration with the surrounding tissues. Particular systems of interest are scaffolds based on hydroxyapatite (HAp), due to its chemical and structural similarity to the inorganic matrix of natural bone and excellent bioactivity. To overcome disadvantages such as poor mechanical properties of HAp it has been combined with polymers and metals. There have been many studies demonstrating the importance of trace elements in bone formation. The introduction of even small quantities of some ions may cause changes/improvements in biological, physicochemical, or mechanical properties.

In our previous studies highly porous HAp and poly(ε-caprolactone),(PCL),-coated HAp scaffolds were prepared using simple and inexpensive methods. In vitro cell culture studies showed that scaffolds are nontoxic and provide an adequate 3D support for the attachment, proliferation and differentiation of MC3T3-E1 cells. Some preliminary studies on preparation of HAp/chitosan scaffolds showed promising results regarding porosity and interconnectivity of pores and nontoxicity.

As a logical continuation of our previous work this project aims to investigate methods to improve mechanical and biological properties of investigated scaffolds, especially the ability to propagate active bone formation. Two different approaches will be investigated: (1) Doping of porous HAp-based scaffolds with trace elements (e.g. Mn, Si, Zn, Cu..)  and (2) Combining HAp with a biocompatible material with a higher mechanical strength, such as titanium (Ti).

The experimental part of research can be subdivided into four subprojects: (1) Preparation and characterization of porous HAp/biodegradable polymer scaffolds; (2) Doping of HAp-based scaffolds with trace elements and their characterization; (3) In vitro studies of HAp based scaffolds; (4) Preparation and characterization of HAp/Ti composites produced by equal-channel angular pressing.

We strongly believe that the research will contribute to the better understanding of the synthesis, structure and properties of scaffolds for BTE applications. Development of novel HAp-based scaffolds could have positive implications for society in terms of treating and healing bone defects, improving quality of life for trauma patients and the elderly. Additionally, the research will open the door to new applications of scaffolds in stem cells research.

   Objectives

The overall objective of HATEA project is to develop and validate new biocompatible hydroxyapatite-based scaffold materials for bone tissue engineering applications.

The specific objectives of the proposed research are:

• to investigate systematically the effect of dopant chemistry on biological performance of the scaffolds in vitro
• to investigate the influence of flow perfusion culture on in vitro cell proliferation, differentiation and extracellular matrix formation
• to investigate the potential of equal-channel angular pressing to produce novel HAp/Ti composite materials for bone tissue engineering applications.