Efeito da laccase associada a catecóis no molhamento em poli (-éter-éter-cetona) (PEEK)

Abstract

Introduction: Alternative materials to titanium have been studied for dental implants and poly(-ether-ether-ketone) (PEEK) has promising properties, except for its low hydrophilic surface. Objective: This study aimed to evaluate whether surface treatment with laccase- mediated catechols would be able to alter wetting capacity, increasing hydrophilia in PEEK. Material and Methods: PEEK disks (20 x 1,5 mm) were previously sterilized with hydrogen peroxide plasma. The catechols (dopa, dopamine and caffeic acid) and the laccase enzyme were dissolved separately in acetate solution pH 4.75 at a concentration of 0.5 mg / ml. The PEEK disks were distributed in the following groups (n = 3): negative control acetate (2 mL), laccase (1 mL laccase 0.5 mg / mL + 1 mL acetate), dopa (1 mL dopa 0.5 mg / mL + 1 mL acetate), dopamine (1 mL dopamine 0.5 mg / mL + 1 mL acetate), caffeic acid (1 mL 0.5 mg / mL caffeic acid + 1 mL acetate); (1 mL dopa 0.5 mg / mL + 1 mL laccase 0.5 mg / mL), dopamine + laccase (1 mL dopamine 0.5 mg / mL + 1 mL laccase 0.5 mg / mL), caffeic acid + laccase (1 mL caffeic acid 0.5 mg / mL + 1 mL laccase 0.5 mg / mL). Samples were incubated at room temperature for 18 hours, washed with distilled water and air dried. The contact angle was measured of 4 μL of distilled water, 0, 10, 30 minutes; 1, 2, 4 and 24 hours after the treatments. New measurements were made after 1 and 2 weeks and 1 month. The obtained values were expressed in mean±SD. Results: Statistical correlations were made in the intragroup and intergroup form. In the intragroup analysis, the contact angles of the laccase (41,1º ± 0,9; p<0,0001) and laccase groups associated with catechols (p<0,0001) remained statistically equal to the immediate one for 30 minutes, but the laccase + dopamine group (18,5º ± 2,3; p<0,0001) sustained the initial value for 2 hours, besides having the lowest angle of contact of all when compared to the acetate control group (85,6º ± 0,6; p<0,0001). Conclusion: The enzymatic treatment in PEEK has proved promising, by substantially reducing the contact angle and promoting an increase in surface wettability and hydrophilia.