Novo epóxi para plastinação: análise de viabilidade e aplicabilidade na conservação de tecidos biológicos

Abstract

Plastination is a technique for preserving biological tissues, the principle of which is the replacement of bodily fluids with a curable polymer. The polymer classes most commonly used in plastination are silicone and polyester and epoxy resins. Epoxy is utilized in 2- to 5-millimeter-thick sections of biological tissues or anatomical segments, with the German resin Biodur® E12 being the most well-known and globally used. There are few alternative epoxies to the reference one (E12) for use in the technique. The objective of this work was to apply a commercial epoxy resin formulation with potential as an alternative to E12 and its curing system in the plastination process of thin sections of biological tissues. The methodology was divided into prospecting for a nationally available resin, adapting the formulation, applying the formulation in the plastination of Wistar rat sections, characterizing the resin, and evaluating the final specimens. From a market search, the E48 epoxy (brand not disclosed) was found, which met the initial prerequisites for testing, and its formulation was altered with the addition of a plasticizer for use in the forced impregnation step. A total of 200 Wistar rat transverse sections were plastinated with the control (E12) and test (E48) polymers in 4 distinct replicates. The results of the shrinkage analysis show no statistical differences between the E12 and E48P resins (with plasticizer, developed in this research). In general, images taken with a confocal microscope showed greater sharpness and contrast for the sections of the E48P formulation. Regarding the characterization of the resins, the E48P formulation stands out for a much lower viscosity compared to the other epoxies tested, resulting from the presence of 35% of plasticizer in its formulation. Additionally, it showed greater flexibility, a faster yellowing rate, and a lower refractive index. Based on the results of the shrinkage analysis, confocal and stereoscopic microscopy, and characterization, it was concluded that the E48P epoxy is a viable alternative to E12.