RESUMO
This article presents details of fabrication, biological activity (i.e., anti-matrix metalloproteinase [anti-MMP] inhibition), cytocompatibility, and bonding characteristics to dentin of a unique doxycycline (DOX)-encapsulated halloysite nanotube (HNT)-modified adhesive. We tested the hypothesis that the release of DOX from the DOX-encapsulated nanotube-modified adhesive can effectively inhibit MMP activity. We incorporated nanotubes, encapsulated or not with DOX, into the adhesive resin of a commercially available bonding system (Scotchbond Multi-Purpose [SBMP]). The following groups were tested: unmodified SBMP (control), SBMP with nanotubes (HNT), and DOX-encapsulated nanotube-modified adhesive (HNT+DOX). Changes in degree of conversion (DC) and microtensile bond strength were evaluated. Cytotoxicity was examined on human dental pulp stem cells (hDPSCs). To prove the successful encapsulation of DOX within the adhesives-but, more important, to support the hypothesis that the HNT+DOX adhesive would release DOX at subantimicrobial levels-we tested the antimicrobial activity of synthesized adhesives and the DOX-containing eluates against Streptococcus mutans through agar diffusion assays. Anti-MMP properties were assessed via ß-casein cleavage assays. Increasing curing times (10, 20, 40 sec) led to increased DC values. There were no statistically significant differences (p > .05) in DC within each increasing curing time between the modified adhesives compared to SBMP. No statistically significant differences in microtensile bond strength were noted. None of the adhesives eluates were cytotoxic to the human dental pulp stem cells. A significant growth inhibition of S. mutans by direct contact illustrates successful encapsulation of DOX into the experimental adhesive. More important, DOX-containing eluates promoted inhibition of MMP-1 activity when compared to the control. Collectively, our findings provide a solid background for further testing of encapsulated MMP inhibitors into the synthesis of therapeutic adhesives that may enhance the longevity of hybrid layers and the overall clinical performance of adhesively bonded resin composite restorations.
Assuntos
Antibacterianos/química , Adesivos Dentinários/química , Doxiciclina/química , Nanotubos/química , Silicatos de Alumínio/síntese química , Silicatos de Alumínio/química , Silicatos de Alumínio/toxicidade , Antibacterianos/síntese química , Antibacterianos/toxicidade , Caseínas/efeitos dos fármacos , Técnicas de Cultura de Células , Argila , Colagem Dentária , Polpa Dentária/citologia , Polpa Dentária/efeitos dos fármacos , Dentina/efeitos dos fármacos , Dentina/ultraestrutura , Adesivos Dentinários/síntese química , Adesivos Dentinários/toxicidade , Doxiciclina/síntese química , Doxiciclina/toxicidade , Humanos , Teste de Materiais , Metaloproteinase 1 da Matriz/efeitos dos fármacos , Inibidores de Metaloproteinases de Matriz/química , Nanotubos/toxicidade , Polimerização , Cimentos de Resina/síntese química , Cimentos de Resina/química , Cimentos de Resina/toxicidade , Células-Tronco/efeitos dos fármacos , Streptococcus mutans/efeitos dos fármacos , Estresse Mecânico , Resistência à Tração , Fatores de TempoRESUMO
The subretinal transplantation of retinal pigment epithelial cells (RPE cells) grown on polymeric supports may have interest in retinal diseases affecting RPE cells. In this study, montmorillonite based polyurethane nanocomposite (PU-NC) was investigated as substrate for human RPE cell growth (ARPE-19 cells). The ARPE-19 cells were seeded on the PU-NC, and cell viability, proliferation and differentiation were investigated. The results indicated that ARPE-19 cells attached, proliferated onto the PU-NC, and expressed occludin. The in vivo ocular biocompatibility of the PU-NC was assessed by using the HET-CAM; and through its implantation under the retina. The direct application of the nanocomposite onto the CAM did not compromise the vascular tissue in the CAM surface, suggesting no ocular irritancy of the PU-NC film. The nanocomposite did not elicit any inflammatory response when implanted into the eye of rats. The PU-NC may have potential application as a substrate for RPE cell transplantation.
Assuntos
Bentonita/química , Proliferação de Células , Poliuretanos/química , Epitélio Pigmentado da Retina/fisiologia , Alicerces Teciduais , Silicatos de Alumínio/síntese química , Silicatos de Alumínio/química , Silicatos de Alumínio/farmacologia , Animais , Bentonita/farmacologia , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Embrião de Galinha , Argila , Feminino , Humanos , Teste de Materiais , Nanocompostos/química , Poliuretanos/síntese química , Ratos , Ratos Endogâmicos BN , Epitélio Pigmentado da Retina/citologia , Epitélio Pigmentado da Retina/efeitos dos fármacos , Engenharia Tecidual/instrumentação , Engenharia Tecidual/métodos , Alicerces Teciduais/químicaRESUMO
A porous clay heterostructure (PCH) from a Mexican clay was prepared and characterized, and its aqueous phenol and dichlorophenols (DCPs) adsorption capacities were studied using a batch equilibrium technique. The PCH displayed a surface area of 305.5 m2/g, 37.2 A average porous diameter, and a basal space of 23.2 A. The adsorption capacity shown by the PCH for both phenol and DCPs from water (14.5 mg/g for phenol; 48.7 mg/g for 3,4-DCP; and 45.5 mg/g for 2,5-DCP) suggests that the PCH has both hydrophobic and hydrophilic characteristics, as a result of the presence of silanol and siloxane groups formed during the pillaring and calcination of the PCH. The values of maximal adsorption capacity for dichlorophenols were higher than those reported for aluminum pillared clays and some inorgano-organo clays and comparable with some ionic exchange resins.