1. Department of Pharmacy, Biopharmaceutics and Pharmaceutical Technology; Saarland University; D-66123 Saarbrücken Germany
2. Pharmaceutics and Biopharmaceutics; Philipps University Marburg; D-35037 Marburg Germany
3. Anatomy and Cell Biology; Medical Faculty; Saarland University; D-66424 Homburg Germany
4. INM - Leibniz-Institut für Neue Materialien gGmbH; D-66123 Saarbrücken Germany