12th Class Biology Biotechnology And Its Applications Devices

Three types of medical devices used nowadays are implants, disposables and external prosthesis.

(1) Implants     

Implants are devices used for replacng a diseased organ or tissue within the body.

Implants must be non-toxic and biocompatible and are used for replacing joint, arteries, heart valves, etc., and occasionally helpful in cosmetic surgery.

Artificial Heart Valve

(i) Artificial heart valves may be either mechanical or made of human or animal tissues.

(ii) Mechanical valves are made from special biocompatible plastics, metal alloys and ceramics.

(iii)  Tissue valves are taken from cadavers of pigs or made from the pericardium of animals.

(iv) Mechanical valves develop tendency of clotting of blood, so the patient must have regular medication of anticoagulants.

(v) Tissue valves do not require anticoagulants, but they tend to calcify, particularly in young.

(2) Disposables

(i) Oxygenator

(a) The first open heart surgery was performed by Walton Lillehel (USA) in 1953 by meant of a procedure, called heart-lung bypass.

(b) Oxygenator is used in open-heart surgery to oxygenate the blood passing through the heart-lung machine.

(c) Oxygenator can be called as an artificial lung. Two common types of oxygenators currently used are bubble oxygenator and membrane oxygenator.

(d) Bubble oxygenators are used for shorter operation whereas membrane oxygenators are more suitable for longer operations and for operation of infants.

Landmarks in Medicine : Diagnosis and Surgery

     (b) Blood Bag

• Blood transfusion is required during surgery, following delivery, for bleeding diseases and after injury.
• Improper transfusion can cause reactions or transmit dangerous diseases such as hepatitis B and AIDS.
• Disposable blood bags reduce chances of spreading diseases.
• Though not prescribed for general use, perfluorocarbons can be used as blood substitute; they dissolve and release oxygen.

    (c) Blood Dialyser (Artificial Kidney)

• Kidney dialysis machine was invented by Willem Kolff, a dutch scientist in 1945.
• A person requires artificial kidney when both of his kidneys fail.
• An artificial kidney can only reproduce the passive filtration process.
• The blood of the patient is passed through the disposable dialyser and is then returned to the body by the intravenous route.
• Haemodialysis means a technique used to remove waste products from the blood.

            · The working of blood dialyser is based on the physical laws of diffusion and osmosis.