1. SURFACE CHARACTERIZATION OF SOME BIOADHESIVES WITH POTENTIAL APPLICATIONS IN MEDICINE. AFM INVESTIGATIONS Introduction Development of resin-based adhesive biomaterials (BA) that can adhere to hard tissue and that can be applied using minimally invasive techniques is a continuous interest of researchers in the field. An accurate analysis of final organization at the bioadhesive surface is necessary for the evaluation of the quality of a hard tissue material. Materials and methods Conclusions Objective The aim of the present work was to investigate the morphology and to evaluate the degradation of the surface of three new experimental resin-based filled bioadhesive systems with potential applications in medicine, particularly in dentistry, exposed to artificial saliva. Results and discussion Cristina Prejmerean 1, Corina Garbo 2, Hodisan Ioana-Maria 1, Ancuta Danistean 2,Ioan Petean 2, Aurora Mocanu 2, Gabriel Furtos 1,2, Maria Tomoaia-Cotisel 2 1 Babes-Bolyai University of Cluj-Napoca, Raluca Ripan Chemistry Research Institute, Kogalniceanu Street, no. 1, 400084 Cluj- Napoca, Romania; 2 Babes-Bolyai University of Cluj-Napoca, Faculty of Chemistry and Chemical Engineering, Arany Janos Street,no. 11, 400028 Cluj-Napoca, Romania 1 st International Conference on Biological and Biomimetic Adhesives COST Action TD 0906 School of Dentistry, University of Lisbon, Portugal 9-11 may 2012 1. Obtaining of bioadhesive systems: Three experimental filled bioadhesive systems have been formulated using a resin based on new synthesized Bis-GMA-type oligomers and three inorganic fillers, an aluminum-fluorosilicate glass, a new synthesized nano hydroxyapatite and a commercial hydroxyapatite (Sigma). The adhesives were stored in artificial saliva for 30 days. 2. The TEM investigation was done using a high resolution transmission electron microscope (HRTEM) TECNAI F30 G2STWIN with EDAX spectrometer 3. The X-ray diffraction investigation was performed using a Panalytical X Pert Pro MPD X-ray diffractometer. A monochrome CuKα radiation filtered with Ni filter was used. 4. The investigation of the surface morphology of the experimental filled bioadhesives was done using the scanning probe microscope, AFM, JEOL 4210 equipment operating in the intermittent contact, tapping mode. The bioadhesives were examined after 1, 7 and 30 days of storage in artificial saliva. The surface roughness, described by the rms (root mean square) value was calculated directly from the AFM observation by the processing of topographical AFM images. After 1 day of storage, the bioadhesive containing the synthesized nano hydroxyapatite (BA1) features the most uniform and compact surface having the minimum sample height, respectively the lowest roughness (133 nm), followed by the bioadhesive containing the commercial hydroxyapatite (BA2) characterized by a roughness of 217 nm and finally by the bioadhesive filled with aluminum-fluorosilicate glass (BA3) which presented the highest surface roughness of 240 nm. After 7 days and respectively 30 days of storage in artificial saliva, the surface roughness was 129 nm and respectively 103 nm in the case of BA1 adhesive system, 208 nm and respectively 125 nm for BA2 adhesive system, 177 nm and respectively 262 nm for BA3 adhesive system. From the view point of the surface uniformity, we can conclude that the smoothest surface results from the bioadhesive based on synthesized nano hydroxyapatite, followed by adhesive system based on commercial hydroxyapatite, and the highest roughness being observed for the adhesive based on glass filler particles. All three bioadhesive systems present rather compact structures and are relatively stable to artificial saliva for 30 days. References 1.Moszner, N., Salz, U. (2001) Progress in Polymer Science, Vol. 26, pp.535-576 2.Tomoaia-Cotisel, M. & colab, (2005) Rev. Roum. Chim., Vol. 50 (6), pp.471-478 3. Prejmerean, C. & colab (2011) Int. J. Nano and Biomaterials, Vol. 3 (4), pp. 334-359 Fig. 8. AFM images for BA2 – 1 day: a) topography, b) phase, c) amplitude, d) 3d view of topography, e) cross section on the white arrow in topography. (scanned area 5 X 5 μm 2 ) Fig. 6. TEM images for the commercial HAP sample: a) overlaid nanocrystals and b) individual nanocrystals. Fig. 7. XRD pattern for the commercial HAP sample. Fig. 3. AFM images for BA1- 1 day: a) topography, b) phase, c) amplitude, d) 3d view of topography, e) cross section on the white arrow in topography. (scanned area 5 X 5 μm 2 ). Fig. 1. TEM images for the synthesized HAP powder : a) uniform nanoparticles and b) high magnification detail. Fig. 2. XRD pattern for the synthesized HAP sample. Fig. 13. AFM images for BA3 – 1day: a) topography, b) phase, c) amplitude, d) 3d view of topography, e) cross section on the white arrow in topography. (scanned area 5 X 5 μm 2 ) Fig. 11. TEM images for the aluminum-fluorosilicate glass: large glass microcrystal and b) close disposed amorphous crystals. Fig. 12. XRD pattern for the aluminum-fluorosilicate glass. Fig. 14. AFM images for BA3 – 7days: a) topography, b) phase, c) amplitude, d) 3d view of topography, e) cross section on the white arrow in topography. (scanned area 5 X 5 μm 2 ) Fig. 15. AFM images for BA3 – 30days: a) topography, b) phase, c) amplitude, d) 3d view of topography, e) cross section on the white arrow in topography. (scanned area 5 X 5 μm 2 ) Fig. 4. AFM images for BA1- 7 days: a) topography, b) phase, c) amplitude, d) 3d view of topography, e) cross section on the white arrow in topography. (scanned area 5 X 5 μm 2 ). Fig. 5. AFM images for BA1- 30 days: a) topography, b) phase, c) amplitude, d) 3d view of topography, e) cross section on the white arrow in topography. (scanned area 5 X 5 μm 2 ). Fig. 9. AFM images for BA2 – 7 days: a) topography, b) phase, c) amplitude, d) 3d view of topography, e) cross section on the white arrow in topography. (scanned area 5 X 5 μm 2 ) Fig. 10. AFM images for BA2 – 30 days: a) topography, b) phase, c) amplitude, d) 3d view of topography, e) cross section on the white arrow in topography. (scanned area 5 X 5 μm 2 )