1. Biomaterials Research Laboratory, Faculty of Materials Science and Applied Chemistry, Riga Technical University, 3 Paula Valdena Street, Riga LV-1048, Latvia;
2. Department of Mechanical Engineering and Mechatronics, Faculty of Mechanical Engineering, Transport and Aeronautics, Riga Technical University, 6B Kipsalas Street, Riga LV-1048, Latvia
3. Biomaterials Research Laboratory, Faculty of Materials Science and Applied Chemistry, Riga Technical University, 3 Paula Valdena Street, Riga LV-1048, Latvia