Sterilization living tissue

Fridman, G., et ah Blood coagulation and living tissue sterilization by floating-electrode dielectric barrier discharge in air. Plasma Chemistry and Plasma Processing 26(4), 425 42 (2006)... 

Processing in Hquid sterilants results in wet products which require highly specialized packaging. Therefore, Hquid sterilization should only be considered if the sterilized article is to be used almost immediately. Liquid sterilants or their residues can be harmful to living tissues. Therefore it is always necessary to rinse articles with sterile water or saline solution foUowing treatment. Whereas Hquid sterilization is an extremely useful method for articles that caimot withstand the conditions of steam sterilization, the problems associated with its use limit its appHcation. 

Medicinal Uses. One of the earliest medicinal applications of the thiol proteases was the use of fig latex as an anthelmintic agent 16, 17). In more recent times papain has been used as a digestive aid in the treatment of dyspepsia and gastric distress. Its usefulness in this respect derives from the fact that papain remains active under acid conditions and is resistant to attack by pepsin. The intraperitoneal injection of sterile solutions of papain has proved to be effective in preventing post-operative adhesions. Papain is sometimes referred to as a T io-logical scalpel because of its specific proteolytic action on dead tissue without affecting live tissue. For this reason it serves as a very useful debridement in the treatment of bums and the removal of scar tissue. When used in combination with antibiotics, it has proved to be effective for topical treatment of ulcerating and infected lesions. 

Contraception. The rapid polymerization of methyl a-cyanoacrylate and its effect on living tissue has been utilized in female sterilization by oviduct blockage (30). In this procedure methyl a-cyanoacrylate is instilled into the oviduct where it rapidly polymerizes into a solid. Subsequent degradation of the polymer leads to formation of scar tissue, which eventually permanently blocks the oviduct. The overall process is shown in Figure 6 (31). 

Direct Plasma-Medical Sterilization of Living Tissue Using FE-DBD Plasma... 

Often the mechanical strength of the metal is an important property (e.g., in the shaft of a needle electrode). Biocompatibility may be critical if a metal comes in contact with living tissue (e.g., with metals used in sterile invasive electrodes). Flexible large electrodes of nickel may generate allergy in human skin. This can be prevented by using an electrolytic salt bridge between the electrode metal and the tissue. 

Positioned in living tissue. In most cases, it is sterile. 

Polymers have been extensively used both as biomaterials, which are constituents of medical devices, and as constituents of drug-delivery systems. Many regulatory requirements must be met in order to use materials in the domain of human health. For instance, sterility is mandatory concerning materials in direct contact with living tissues in the absence of a barrier such as the intact skin. In addition, both polymers and devices have to be biocompatible, and their biocompatibility has to be evaluated by in vitro and in vivo tests. 

Before contact with the living tissues of animals or humans, polymers and devices have to be sterilised. Even if fabrication is performed in a clean room , the materials and processing machinery are not sterile. In addition, it has been shown that some bacteria that are normally benign and easily eliminated by the body s defence systems become pathogenic and drug-resistant when present on the surface of devices. 

Disinfection is defined as a process that greatly reduces or eliminates viable microorganisms on nonliving surfaces. It is to be distinguished firom antisepsis, which is the same process but applied on living tissue, such as human skin. Neither should be confused with sterilization, which consists, of the total destruction of microorganisms, including spores. 

One of the most widely used hydrogels is water-swollen, crosslinked poly(2-hydroxyethyl methacrylate) (PHEMA) which was introduced as a biological material by Wichterle and Urn [33]. The PHEMA structure permits a water content similar to living tissue. The hydrogel is inert to normal biological processes, shows resistance to degradation, is permeable to metabolites, is not absorbed by the body, withstands heat sterilization without damage, and can be prepared In a variety of shapes and forms [34]. 

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