The Preservation Process
This educational exhibition is made possible due to the unique method of preservervation often referred to as “polymer impregnation” or “plastination” - a process that replaces the body’s water and fat with reactive plastics. Polymer preservation is a method whereby the bodily fluids are replaced with liquid and is then hardened to create a solid, durable anatomic specimen that will last indefinitely.
The process leaves even the finest, most delicate tissue structures intact, making the resulting specimens invaluable for medical study because the organs remain identical to their pre-preservation states. The plastic is initially pliable, which enables the specimens to be placed in many different "everyday" positions and eventually hardens into the basic, practical positions you will see on display within the exhibit.
A typical specimen goes through a long process of preparation, fixation, and ultimately presentation, without the hazards associated with unpleasant toxic fumes and potentially unsafe and difficult handling procedures. Prior to the invention of polymer impregnation, the only method for preservation of cadavers for medical study was storage in formaldehyde, making the dissection of human bodies cumbersome. The improved attributes of polymer impregnated specimens are accounted for by the superior qualities of the curable polymers. Because the specimens are dry, odorless, and durable, they are an excellent teaching and research tool.
STANDARD PROCESS OF POLYMER IMPREGNATION
Water and lipid tissues are replaced by curable polymers which include silicone, epoxy and polyester-copolymer, and require 4 primary levels of processing:
Fixation - The body is embalmed, usually in a formaldehyde solution, in order to halt decomposition.
Dehydration - After any necessary dissections take place, the specimen is then placed in a bath of acetone. Under freezing conditions, the acetone draws out all of the water and replaces it inside the cells.
Forced Impregnation - In the third step, the specimen can then be placed in a bath of liquid polymer, such as silicone rubber, polyester or epoxy resin. By creating a vacuum, the acetone is brought to a boil. As the acetone vaporizes and leaves the cells, it draws the liquid polymer in behind it, leaving a cell filled with liquid plastic.
Hardening - The plastic must then be cured, either with gas, heat, or UV light in order to harden it. A specimen can be anything from a full human body to a small piece of an organ and are known or referred to as either "plastins" or "plastinates".