Application Of PTFE In Medical Treatment

  Various polymer products are widely used in modern medical treatment. These products are not only used in the human body and in contact with tissues in the human body, but also used in various equipment in the medical field. In recent years, polymers have greatly excluded and replaced the applications of metals and other materials in the medical field.

  Here only the application of polytetrafluoroethylene (PTFE) in this field is introduced. PTFE is the most widely used material in fluoroplastics.

  As we all know, polymer products used in medical treatment can be roughly divided into three categories:

  (1) Products directly into the human body (permanent or temporary). The polymer products that permanently exist in the organic body include implants (artificial substitutes for tissues and organs). Temporary use includes catheters, drainage tubes, earpieces, filters, ventilation devices, etc. They are mainly used for the transportation of substances and gases, the filtration of media, etc;

  (2) Products for external use. Some properties of polymers, such as plasticity, lightness, firmness, tightness and elasticity, stability to corrosive media, electrical insulation, etc., are very important for this kind of products. These products include gloves, tourniquets, limb fixation devices, external sheaths of various diagnostic devices, etc;

  (3) Functional elements of biochemical analysis and biochemical synthesis equipment, culture, regeneration and propagation devices of cells and tissues, etc.

  Fluoroplastics are the most widely used in the first category. Fluoroplastics can be used in vivo because of their certain properties, such as obvious biological inertia and strong pore forming ability after special treatment.

  Using the biological inertia of polymers, implants that do not cause organic rejection can be produced on the basis of this performance, and a device in contact with blood can be developed, which will not damage the blood.

  If necessary, the porous structure of modified PTFE can become the forming matrix of organic cells and tissues. The prepared with certain diameter, pore characteristics and micro fluctuation of surface can make this or that kind of tissue grow directionally in the polymer structure and restore the lost function of organs or tissues. The most obvious examples are used to treat the most popular diseases of our time - atherosclerosis and vascular substitutes. Due to the special properties of PTFE, the vascular substitute made of PTFE is better than the analogues made of other materials, and can play a function similar to natural blood vessels. The Dingxing tube sewn to the blood circulation system is adapted by cells and tissues, and its inner surface (blood flow surface) is covered by blood fibrin (a physiological polymer in the blood like a monomer) and cells produced by collagen. Blood fibrin and cells penetrate into the micropores of the substitute blood vessel, firmly combining the backing layer of blood fibrin with the substitute wall. The fastness of blood fibrin to the wall of the substitute is particularly important, because if blood fibrin produces delamination, it will inevitably lead to the blockage of blood vessels. Over time (from March to April), blood fibrin will be replaced by more stable and stronger biopolymer collagen. Tissue and new adventitia also grow outside the artificial blood vessel. The new adventitia keeps the graft firmly positioned. PTFE substitutes for bone tissue, membrane and soft tissue also play a similar role.