Artigos
URI permanente para esta coleçãohttps://repositorio.fei.edu.br/handle/FEI/800
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- Biocompatibility of polyvinyl alcohol/trisodium trimetaphosphate as vitreous substitute in experimental vitrectomy model in rabbits(2022-02-05) OLIVEIRA, R. A. DE; MURALHA, F. P.; GRUPENMACHER, A. T.; Andreia de Araújo Morandim Giannetti; BERSANETTI, P. A.; MAIA, M.; MAGALHÃES JUNIOR, O.© 2021 Wiley Periodicals LLC.Synthetic hydrogels have been proposed as vitreous substitutes recently. This study aims to evaluate the biocompatibility of polyvinyl alcohol (PVA) crosslinked with trisodium trimetaphosphate (SMTP) hydrogel in rabbit vitrectomized eyes. Seven animals were submitted to pars plana vitrectomy and the vitreous was replaced by PVA/SMTP hydrogel. Optical coherence tomography, fluorescein angiogram, clinical, and electrophysiological (ERG) examinations were analyzed at baseline, on postoperative days 7 and 30. The fellow eye was used as the control group. Hydrogel opacification was observed and ERG recordings were reduced in the hydrogel group in rod response, b-wave cone response and flicker. A histological analysis showed retinal disorganization, presence of multinucleated cells, and intraretinal hydrogel particles. The PVA/SMTP hydrogel showed poor biocompatibility. Novel biomaterials compounds should be analyzed in vivo.
- DSC evaluation of cross-link development induced by laccases in corneas(2022-11-25) Andreia de Araújo Morandim Giannetti; CARVALHO, T. S.; DE ANDRADE NETO, J. C.; BERSANETTI, P. A.© 2022, Akadémiai Kiadó, Budapest, Hungary.Several studies have been developed aiming at new treatments for ophthalmological problems such as keratoconus, an eye disease that leads to the reduction of cross-links between the corneal collagen fibrils. Corroborating these studies, this work evaluated the increase of cross-linking in enucleated porcine eyes treated with catechin in the presence of laccase. The ideal conditions for the treatment of the cornea to promote the development of cross-links were determined through the application of a design of experiments. The input variables were the concentration of laccase and the reaction temperature, and the output variable was the enthalpy of corneal denaturation. The DSC results show that the ideal laccase concentration was 8.0 mg mL−1 and the temperature was 36.0 °C. The catechin concentration used was 5.0 mg mL−1. This condition led to a 10.8% increase in the denaturation temperature and a 110.3% increase in the denaturation enthalpy. Enzymatic degradation tests showed that within 24 h of digestion the group treated with laccase in the presence of catechin was more resistant compared to the control group. A decrease of 34.7 and 55.6% in the relative area and relative mass of corneas in the control group was verified, while for the group treated with laccase these values were 41.7 and 8.5%, respectively.