Plastination

Since the founding and research of how the Egyptians managed to preserve bodies for thousands of years, many other methods of preservation have been discovered for various purposes. Plastination is a method unique in the preservation of durable anatomical or perishable biological specimens, especially organs with a high water contents (brain, heart, liver, muscle, joint specimens and body slices), while retaining a lifelike condition, plastination involves the replacement of the tissue water and lipid with a curable plastic polymer. The class of polymer used determines the optical (transparent or opaque) and mechanical (flexible or firm) properties of the impregnated specimen. The specimens preserved in this manner are permanent, clean, odourless, durable, non-toxic, dry last indefinitely, and can literally be grasped. They even retain their original surface relief and cellular identity down to the microscopic level. A variety of plastination methods, each having its own advantages and disadvantages are available.

Pioneer of Plastination

Günter von Hagens is the inventor of the plastination process. He started studying medicines at the University of Jena in 1965. Protesting against the invasion of the Warsaw Pact troupes in Czechoslovakia in 1968, he was arrested though he made an effort to escape from East Germany. Upon his release only in 1970, he continued studying and graduated from the University of Lübeck in 1973. He started working on developing the plastination process in 1977 and by 1978 it could already almost be used as he continued to research at Heidelberg University. He later engaged a company called BIODUR for the development and shipping of the machinery and auxiliaries for the plastination, and in 1993 he founded the Institute for Plastination. Ever since then, many applications have been derived from this unique process. Plastination is carried out in many institutions worldwide and has obtained great acceptance particularly because of the durability, and the high teaching value plastinated specimens have.

Uses of Plastination

With plastination, it is now possible for a non-physician to take such a close look at the human body and its inner structure.

Another fact that contributes to the overwhelming interest in Von Hagens' work is the immanent confrontation with death, an important though, closing part of our lives, which is neglected in our societies. Few people have actually seen a dead body with their own eyes. And those who have have done so mostly through a formalised event such as a funeral. Von Hagens exhibition allows us to overcome that taboo by literally being in contact with the dead.

Plastination is a relatively new and unique method of preserving tissue in a prolonged lifelike state. It is a vacuum process in which biological specimens are impregnated with a reactive polymer like silicone rubber, epoxy or polyester resin. Decay, though a necessary process in nature but is impediment to morphological studies and research that requires biological specimens to be preserved for future research. Therefore, the founding of plastination is useful for research or experiments that requires long-term preservation, especially for an anatomist.

Plastinated specimens are now routinely used to great benefit in teaching gross anatomy and neuroanatomy. The durability and safety of plastinated specimens would hence be utilized in a much broader range of educational settings. For example, specimens of normal lung and lung tissue from smokers and victims of smoking-related cancer have been used in a number of elementary, middle and high schools across the state to promote the prevention of smoking.

Plastinated specimens can be repeatedly handled by students without deterioration and specimens can be stored as would any inert object.. The plastination facility is to enhance older versions of preservation to provide plastination services to other departments and institutions. Plastination is carried out in many institutions worldwide and has obtained great acceptance particularly because of the durability, and the high teaching value plastinated specimens have.

Technical Process

The technical process of plastination consists of 4 main steps:

Fixation
Dehydration
Forced Impregnation/ Defatting
Hardening (Curing)/ Plastination

For fixation, any conventional procedure would be suitable for application. The usual fixatives as formaldehyde solution, Kayserling solution would be able to achieve the effect by fixation needed. During fixation of hollow organs it must be dilated as well as during dehydration and gas curing.

After fixation, the specimen is put into an agent for dehydration, either alcohol or acetone to occur, of which acetone of up to three bathes of -25°C cold acetone (to avoid further shrinkage) is usually used as intermediary solvent during the next step - forced impregnation.

After dehydration it is put in acetone at room temperature for defatting. Defatting is usually known as forced impregnation, a process that can be achieved by ethylene chloride. Forced Impregnation is the central step of plastination. The specimen, soaked with the volatile solvent, is placed into a polymer solution. Vacuum forces the acetone out of and the polymer into the specimen when applied. Hence, the intermediary solvent is continuously extracted in its gaseous state. The evaporating acetone creates a volume deficit within the specimen drawing the polymer into the tissue as its replacement.

When coming to the hardening process or curing process, there are 4 variations:

Silicone impregnated specimens are flexible and resilient, making them useful for teaching and allows the broadest range of application since it is suited for any kind of tissue able to be purified and it provides satisfactory results with minimum equipment. Polymerizing emulsion (PEM) produces specimens that are opaque as silicone specimens but rigid; this technique is mainly used for archaeological wood and thick body slices that are more than 1 cm in length. Thin body and organ slices are produced with epoxy resin resulting in transparent specimens with good colouration of different tissues. They produce firm products and so are used for thin, transparent body or organ slices. Epoxy itself is totally colourless and transparent. Polyester copolymer is exclusively used for brain slices allowing a particular good discrimination between fiber and nuclear area preserving the visual distinction between gray and white matter.

Advantages of Plastination

Plastination is a relatively safe, cheap and easy for storage and transportation purposes as compared to liquid nitrogen storage, which would cost more and requires a certain level of expertise due to its potentially dangerous (freezer burn) nature where there might be presence of asphyxiation. A plastinated brain could be stored just about anywhere though preferably in a cool, dark place to minimize tissue & polymer deterioration.

Potential Disadvantages of Plastination

Though the disadvantages of plastination are not yet clearly pointed out, these are some likely conditions that might occur. At room temperature, there might still be some decay though it might be slow, regardless of the vacuum, chemical fixation, dehydration & defatting. Assuming that plastination alone already significantly slows down decomposition, then the plastinated organism would be affected biologically. And similar to cryonics, plastination itself might cause "irreversible" information loss in the brain.

There is still another problem that plastination would have to deal with. The ethical and moral grounds of plastination comes in when people questions if humans should be plastinated. Should the dead human body be treated as merely a piece of art or should the body be treated in the same manner for other reasons? There would still be people reluctant or refusing to accept plastination.

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