1. György Váró Institute of Biophysics, Biological Research Center Szeged, Hungary Lamorlaye, May 2011

2. 2 Mannitol treatment of the cerebral endothelial cells Blood-brain barrier: Mannitol: HO - CH 2 – (CHOH) 4 – CH 2 - OH

3. 3 Before treatment After treatment

4. 4 Before treatment After treatment

5. 5

6. 6 8 kPa 0.9 kPa 0 0.2 0.4 0.6 200 0 -200-400-600 force (nN) distance (nm) S M C A

7. 7 Z. Bálint, I.a. Krizbai, I. Wilhelm, A.E. Farkas, Á. Párducz, Z. Szegletes and G. Váró (2007) Changes induced by hyperosmotic mannitol in cerebral endothelial cells: an atomic force microscopic study. Eur. Biophys. J. 36. 113-120

8. 8 Effect of the calcium starvation on the cells: Healthy endothelial cells -Ca 2+ Ca starved cells

9. 9 +Ca 2+

10. 10 I. Wilhelm, A.E. Farkas, P. Nagyőszi, G. Váró, Z. Bálint, G.A. Végh, P.O. Couraud, I.A. Romero, B. Weksler and I.A. Krizbai (2007) Regulation of cerebral endothelial cell morphology by extracellular calcium. Phys. Med. Biol. 52. 6261-6274

11. 11 Petri Dish 8 µm Filter AFM cantilever Matrigel RBEC Layer A2058 Transmigration of the melanoma cells

12. 12 A2058 on RBEC layer

13. 13 3

15. AFM cantilever tip on hard surface Petri dish

16. AFM cantilever tip on hard surface dwell time load

17. AFM cantilever tip on living cells

18. Stress relaxation

19. AFM tipless cantilever with melanoma cell on living cells

21. AFM tipless cantilever with melanoma cell on fixed cells

22. Adhesion force: Melanoma cell on hard surface Melanoma cell on living cell layer Melanoma cell on fixed cell layer

23. Stress relaxation force Melanoma cell on hard surface Melanoma cell on living cell layer Melanoma cell on fixed cell layer

24. Adhesion force properties: Numbers of jumps Size of the jumps

25. 25 Living cells Fixed cells Size of the jumps

26. Stress relaxation fast exp.

27. Stress relaxation slow exp.

28. 28