Plastination

This ppt will give the readers an idea about the procedure of plastination.

1. PLASTINATION by: Dr. Ravi Kant Narayan 3 rd yr JR Department of Anatomy Pt. B. D. Sharma PGIMS, Rohtak, Haryana, India

2. Plastination is the method of long term preservation of the biological tissues with completely visible surface and high durability. It was developed by Dr. Gunther von Hagens in 1978 at the Heidelberg University in Germany.

3. In this technique, the water and fat of the body are replaced by certain polymers. The specimens obtained after plastination are called as PLASTINATES.

4. Requirements

5. Primarily, we require a lab equipped with fire extinguishers, explosive proof lighting system and a freezer motor fitted outside the room. The room should have multiple extraction points and should be well equipped for possible spillages.

6. Other materials required have been classified into 2 groups: A. Chemicals B. Equipments A. Chemicals required: Formalin (≤ 10%) Acetone or methyl alcohol Silicone or epoxy polymer Biodur S3 or S6 (hardener) Water.

7. B. Equipment required: 1. Containers depending on size of specimen 2 . Deep freezer, motor system to create vaccum 3. Pressure gauge to measure the pressure.

8. After procuring, the samples are prepared properly before undergoing the procedure to form plastinates . For example: 1. Hollow organs need to be flushed, cleaned and then fixed in a dilated position. Dilation of hollow organs will increase the flexibility of the organs due to the thinner wall .

9. 2. Intestinal specimens may be opened to remove ingest, sutured closed and then dilated. 3. Ostia with strong sphincters must be held open with appropriate sized cannulas or by tubing.

10. 4. Intravascular injection of colored silicone, gelatin , latex or epoxy may be used to highlight vessels, etc.

11. Procedure of Plastination

12. There are four steps in the standard process of plastination : 1. Fixation 2. Dehydration 3. Forced impregnation in a vacuum 4. Hardening or Curing

13. FIXATION (1-4 Days)

14. Under fixation, the body is embalmed, usually in a formaldehyde solution in order to prevent the decomposition of the body. Usually 10 % formaldehyde solution may be used as a fixative, lower percentage formalin solutions may produce less bleaching of the specimen.

15. Minimal fixation with low percentage of formalin and short time duration (1-2 days) will yield a specimen which is more flexible and more natural looking. Fixation of hollow organs is necessary to maintain the shape and lumen of the organ

16. DEHYDRATION (4-5 weeks)

17. Equipment: Deep freezer with containers

18. Dehydration removes the specimen fluid at -25°C. In this step, tissue fluid is replaced with an organic solvent i.e acetone.

19. First, the specimens are washed in running tap water for two days with the aim of neutralizing the formalin/preservative fumes during dissection. Tissue water and lipids were removed by subjecting the specimens to at least three changes of acetone bath at one-week interval in every change.

20. The specimens were turned/agitated at least once a day so as to ensure maximum action of the acetone on the specimens. Acetone turns yellow when fats are removed.

21. Degreasing would be considered complete when the acetone bath remains clear. Acetone is used in most cases because, acetone also serves as the intermediary solvent during the next step of forced impregnation and it can be recycled.

22. Acetone also helps in removal of fat at room temperature of 20° to 25°C. An acetone amount of 10 times the specimen weight is best for good results.

23. FORCED IMPREGNATION IN VACCUM

24. Equipments : Deep freezer (explosion proof or motor and compressor removed and placed in a different room); Vacuum chamber,

25. 3. Vacuum pump with pressure gauge (Vacuum is complete when the pressure is around 5 mm Hg)

26. This is the central step, where the intermediary solvent (acetone) is replaced with a curable polymer such as silicone, epoxy resin, polyester resin, etc under applied vaccum .

27. The dehydrated specimen is placed in a bath containing liquid polymer. After some days of immersion, vacuum is applied to it.

28. Vacuum is increased gradually to boil the intermediary solvent (acetone), which has a lower boiling point (+56 ° C) out of the specimen. Impregnation is monitored by watching the formation of bubble on the surface of the mixture. Absence of bubbles indicates completion of the procedure.

29. Structure of hydroxyl-terminated polydimethyl siloxane. [Si - O] represents a basic silicone molecule.

30. HARDENING or CURING (4-5 weeks)

31. Equipment: plastic box, stretch foil, membrane (aquarium) pump.

32. Finally, the polymer inside the specimen has to be cured (hardened). This is achieved by exposing the impregnated specimen to a hardener which can be liquid (S3) or gaseous (S6) in nature .

33. S6 is a liquid that vaporizes at room temperature and causes fast curing. The impregnated specimen and a bowl filled with curing agent is placed in a tightly closed chamber for several weeks.

34. To enhance the curing procedure air may be bubbled through the fluid. For complete curing, the specimen should be kept in a plastic bag for several weeks.

35. The hardener commences end to end-linkage and hence elongation of the silicone molecules, which produces increased viscosity of the reaction mixture. This linkage is reported to enhance flexibility of the impregnated specimen

36. Gas Curing Box with Supplying unit

37. Curing methods have potential problems and/or disadvantages. 1. A white precipitate may appear on the specimen. 2. The specimen may shrink. 3. Oozing polymer may coat the specimen

38. To avoid precipitations: 1. Use a desiccant, e.g. calcium chloride. 2. Pour the fluid gas cure into the dish and then place the specimens into the gas chamber.

39. 3. Use slow curing, because precipitates hardly ever form. 4. Decrease exposure time to the S6 vapour and/or allow the excess S6 to evaporate from the cured specimen.

40. To avoid shrinkage: 1. Wrap the specimen with thin foil which will adhere to the surface of the specimen. 2. Use slow cure only on specimens which have been formalin-fixed for a prolonged period

41. Types of Plastination

42. 3 types:- Whole body plastination Luminal plastination Sheet plastination

43. Whole body / organ plastination In this process entire body or an organ is plastinated. Total structure and relationships of an organ/body are preserved.

44. Two plastinated bodies positioned as rugby players.

45. Plastinated Heart & Lung Specimens of a Smoker and a non – Smoker.

46. Plastinated Thoracic and Abdominal Organs in their Usual Configuration

47. It is done for hollow organs like lungs, stomach, intestine, ventricles of brain, vascular pattern of heart and kidneys. Specimens are dilated/ inflated during fixation, dehydration and curing. Beautiful and precise bronchial pattern can be seen by this technique. Luminal plastination

48. It involves making of thin transparent or thick opaque sections of body or an organ. These sheets are portable and display cross sectional anatomy comparable to CT or MRI scan sections. Sheets can be made in various planes. Sheet plastination

49. Thin sections (1-2mm) correlates well with routine histology slides. Polymers such as epoxy, polyester or polypropylene (araldite) resins can be used for making sheet plastinates . Sheet plastination

50. Sheet plastinates of Transverse sections of body at different levels.

51. Horizontal brain slice Longitudinal slice of the head

52. Advantages of Plastination

53. The specimens are dry, easy to handle, store, transport and long lasting. There will be no formalin fume irritation on the dry specimens (devoid of harmful effects of formalin exposure).

54. 3. Plastination can accommodate a variety of specimens from gross specimens to cross section slices & therefore, can be used as an ideal alternative method of specimen preparation for teaching and research purposes.

55. Disadvantages of Plastination

56. Costly procedure Time consuming Requires skilled technical support to carry out the procedures and in handling the equipment.

57. 4. Prepared specimen requires handling with care. Chemicals used, such as acetone are highly inflammable and should be used in places equipped with fire extinguishing measures.

58. REFRENCES Gunther von Hagens ' BODY WORLDS, Institute for Plastination , Heidelberg, Germany, www.bodyworlds.com . Holiaday SD, Blaylock BL, Smith BJ. Risk factors associated with Plastination : Chemical toxicity considerations. 2001, J Int Soc Plast16:9-13. Hagens GV, Tiedmann K, Kriz W. The current potential of plastination . Anat Embryol (1987) 175:411-21. Sargon MF, Tatar I. Plastination : basic principles and methodology. Anatomy 2014;8:13–8. Dhanwate AD, Gaikwad MD. Plastination – A Boon to Medical Teaching & Research. IJSR 2015;4(5):1550-3.

59. Thank YOU…!!!