Plastination of Coronal and Horizontal Brain Slices using the P40 Technique

The Biodur polymer P40 is a UV light cured polyester which is used for the production of thin brain slices. P40 may also be used for the production of transparent, plastinated, body slices. It was found that in the case of brains, thorough and even fixation is absolutely critical to the final quality of the slices and in particular to prevent the occurence of orange discolouration of the tissue. Brains were suspended in 5% formalin at +5°C over a period of 9-11 weeks with frequent changes of fixative. During this time, when the brains were firm enough, they were sliced to allow better penetration for the fixative. After fixation 3 slices were processed at a time. The slices were flushed in running water, dehydrated in -25°C acetone then immersed in P40 polymer at -25°C. Impregnation was undertaken in a vacuum chamber at room temperature. The P40 bath within the chamber was surrounded with ice packs to prevent the polymer wanning too quickly while acetone was being evacuated. Following impregnation the slices were cast individually in flat, glass chambers and then cured under UVA lights. After the sheets were removed from the chambers they were trimmed and the edges sanded and polished.