IIW White Paper

9.16.2 Joining live tissues and coatings Joining of live tissues and coatings is a new emerging area with great innovation potential. The E.O. Paton Electric Welding Institute in the Ukraine developed and practically realised the possibility of making permanent joints on live tissues. Welding of live tissues was tested and approved for use in surgical operations (without restrictions) by medical supervision authorities. There is a need to get a deeper insight into the principles and nature of joining of live tissues and their regeneration in a living body. Investigations should continue to study biological peculiarities of joining of live tissues with implants. The range of artificial organs is widening, and there is a need to develop principles for their joining and compatibility with living organisms. New methods of hyperthermic treatment show high promise. High-temperature surgical technique is a new area in surgery, the development of which was started in Ukraine early in the 1990s. High-temperature (100-10,000 o C) effects on tissues of a living body allow performing separation (cutting) and joining (welding) of live tissues, arresting of bleeding (punctuate and parenchymatous), treatment of wounds for their sterilisation, acceleration of healing and prevention of wound infection. One of the promising fields in high-temperature surgery is affecting live tissues with flows of low-temperature gas-discharge plasma or heated gases. First of all, here one may distinguish such medical technologies as plasma cutting (destruction), coagulation and welding (joining) of live tissues. The jet of the low-temperature argon plasma required to implement these technologies is generated by special devices, i.e. indirect-action arc plasma torches. Another method for joining live tissues is thermal-spray welding, which consists in affecting tissues with a flow of hot gas generated by special devices. This method provides restoration of integrity of hollow organs and suppression of bleeding in surgical interventions by achieving a positive physiological effect and adequate recovery of tissues in the zone of welds (no-ligature). This method is also efficient for treatment of purulent wounds, as it exerts a deleterious effect on wound infection and prevents its development. Plasma and thermal-spray methods of high-temperature surgery have been studied for the last five years in live animal experiments on white rats, rabbits and pigs. The results obtained are indicative of a high promise of further technical and medical studies of the above methods, development of new equipment for their wide clinical application, and development of new medical technologies.

9.16.3 Hot topics The main areas in welding of live tissues are:

Utilisation of new sources for thermal-biological treatment of welded joints. Investigation of the nature of formation of joints on live tissues and biocompatibility of implants.

Development of methods for joining live and artificial organs by welding. Optimisation of joining equipment and materials, widening of clinical practice.

9.17 Nanotechnology and nanojoining sector Nanotechnology stands for the exploitation of nano effects. These are special material properties which a material displays from a certain size - as a rule from 100 nanometers and below (1 nm =10- 9 m). These special properties, which the material does not display on a macroscopic level, result from surface properties that predominate relative to the volume properties and that cause a quantum-mechanical behavior of the building blocks of matter. An effect that is very widely known, for instance, is the Lotus effect. The use of

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Through Optimum Use and Innovation of Welding and Joining Technologies

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