P96 Technique for Tissue Plastination in Preparing Long-Lasting Anatomical Specimens

Background: Plastination is a technique of long-term preservation of the natural tissues without the typical problems related to wet specimens. Plastinated specimens are durable, dry, and flexible. In this process, the water and fat in biological tissues are substituted by a curable polymeric resin, i.e., subsequently cured. In this study, a new unsaturated polyester resin (P96) was synthesized and formulated to improve plastination techniques. These approaches were applied in the plastination laboratory at Isfahan Medical School based on our previous synthesized resin (P87) and the commercial resin (P35). Methods: P96 was formulated using different polyols, saturated, and unsaturated poly-acids, as the ploy esterification monomers. Then, the resulted pre-polymer was cured by the reaction of a vinyl monomer (hardening agent) in the presence of a radical initiator (hardening promoter) to form a tough durable film. The components of the resin were finely tuned to achieve the desired properties for organ plastination. Then, forced impregnation in a vacuum chamber was performed in the presence of P96 at 25oC following the conventional protocol, fixation, slicing (if necessary), dehydration, and defatting (if necessary). Finally, the curing (hardening) of P96 specimens was achieved by UVA-light irradiation. Results: According to the mechanical test results, P96 presented higher tensile strain and flexibility than P35 and P87. P87 had higher bending capability, compared to P35 and P96. P96 specimens were lighter, compared to P35 and P87 specimens. P96 specimens were more odorless than P87 specimens. In the naked survey of specimens, P96 specimens presented a better appearance concerning natural color and texture for plastinated specimens as well as the resin uniformity, consistency, and transparency of cadaveric tissues. Conclusion: The current study introduced a novel plastination method using a new formulated resin, P96. This technique is a quick and less expensive method for producing sheet as well as bulk plastinated specimens of different organs, i.e., appropriate in teaching anatomical sciences. P96 can be considered an upgraded resin, i.e., transparent and flexible with an easy and controllable hardening process. It has resolved the deficiencies of previous polyester resins.