A possible use of melatonin in the dental field: Protein adsorption andinvitrocell response on coated titanium

Abstract

Melatonin (MLT) is widely known for regulating the circadian cycles and has been studied for its role in boneregeneration and inflammation. Its application as a coating for dental implants can condition the local micro-environment, affecting protein deposition on its surface and the cellular and tissue response. Using sol-gelcoatings as a release vehicle for MLT, the aim of this work was to assess the potential of this molecule inimproving the osseointegration and inflammatory responses of a titanium substrate. The materials obtained werephysicochemically characterized (scanning electron microscopy, contact angle, roughness, Fourier-transforminfrared spectroscopy, nuclear magnetic resonance, Si release, MLT liberation, and degradation) and studiedinvitrowith MC3T3-E1 osteoblastic cells and RAW264.7 macrophage cells. Although MLT application led to anincreased gene expression of RUNX2 and BMP2 in 10MTL, it did not improve ALP activity. On the other hand,MLT-enriched sol-gel materials presented potential effects in the adsorption of proteins related to inflammation,coagulation and angiogenesis pathways depending on the dosage used. Using LC-MS/MS, protein adsorptionpatterns were studied after incubation with human serum. Proteins related to the complement systems (CO7,IC1, CO5, CO8A, and CO9) were less adsorbed in materials with MLT; on the other hand, proteins with functionsin the coagulation and angiogenesis pathways, such as A2GL and PLMN, showed a significant adsorption pattern.