Objectives . The purpose of this study was to evaluate, by means of tensile bond strength (TBS) test, the influence of Mefp-1-based peptides chain configuration as well as DOPA aminoacid role on chemical interaction to zirconium oxide ceramics.
Materials and methods . Aminoacid sequences derived from Mytilus edulis foot protein 1 (Mefp-1) were synthesized applying the Fmoc-strategy (A433 Solid Phase Peptide Synthesizer, Applied Biosystems). The purification was accomplished by HPLC (BioCad 700E; PerSeptive BioSystems). The original sequence was diversified into six experimental peptides (see table of results), being four of them single deca-peptides and two duplicated deca-peptides. The role of DOPA adhesion was evaluated by testing it alone, swapping its position in the peptide sequence and doubling its concentration in the sequence. Onto the surface of 3 × 3 × 9 mm zirconium oxide ceramic bars, 2.5 μl of peptide solution in 0.1% TFA was applied and oxidized with 1 μl saturated KIO 3 . The zirconia bars were bonded together by one surface in a perpendicular orientation (cross-shape) and stored for 7 days under a 5-g brass weight. The bonded specimens were mounted in an universal testing machine (Zwick/Roell) and pulled in tension by a wire. Tensile bond strength was given in MPa by dividing the force in N by the adhesion area (≅9 mm 2 ). Data were analysed by one-way ANOVA and mod. LSD-test ( p < 0.05).
|Sequence||TBS (MPa) in zirconia|
|DOPA||1.0 ± 0.65 (d)|
|Ala-Lys-Pro-Ser-Tyr-Hyp-Hyp-Thr- Tyr -Lys||2.71 ± 1.47 (a,b)|
|Ala-Lys-Pro-Ser-Tyr-Hyp-Hyp-Thr- DOPA -Lys||1.74 ± 1.25 (b,c,d)|
|Ala-Lys-Pro-Ser- DOPA -Hyp-Hyp-Thr- Tyr -Lys||1.49 ± 1.18 (c,d)|
|Ala-Lys-Pro-Ser- DOPA -Hyp-Hyp-Thr- DOPA -Lys||2.41 ± 1.45 (a,b,c)|
|Ala-Lys-Pro-Ser-Tyr-Hyp-Hyp-Thr-Tyr-Lys-Ala-Lys-Pro-Ser-Tyr-Hyp-Hyp-Thr- DOPA -Lys||3.40 ± 1.29 (a)|
|Ala-Lys-Pro-Ser-Tyr-Hyp-Hyp-Thr- DOPA -Lys-Ala-Lys-Pro-Ser-Tyr-Hyp-Hyp-Thr- DOPA -Lys||2.61 ± 1.31 (a,b,c)|