Liquid fluorocarbon

Shortly after the liquid-breathing expenment [f] was published, the same liquid was used to perfuse an isolated heart from an animal [6], by intermittent perfusion with typical aqueous buffer and fluorocarbon Then Sloviter [7] showed that an emulsion of this fluorocarbon liquid, made by ultrasonication with an albumin solution, could sustain the life of the brain of a rat as well as or better than perfusing... 

The final steps to a synthetic blood depend completely upon good chemistry tailored to meet the exact needs of the body Fluorocarbons, such as perfluorodecalin, recently have been found to induce hypennflated lungs when given either intravenously as an emulsion or mtratracheally as a neat liquid [18, 19] But this and other physiological side effects are now understood, and research is well advanced to prevent undesirable side effects in medical applications of fluorocarbon liquids... 

More recently, other heavier than water products have been developed for temporary internal tamponade. These are fluorosilicones [46,47], semifluorinated alkanes [1,7], heavy fluorocarbon liquid (HFCL) oligomers [5,7] and solutions of fluorine-containing compound and silicone oil [8-10,47],... 

This chapter presents the state of the art of the use of highly fluorinated liquids in ophthalmology and perspectives of future applications in the eye. In different medical disciplines, the characteristics of these fluids are directly used, like in the case of ocular endotamponades in ophthalmology, of gas carriers in liquid ventilation, or of preservation and transport media in transplantation medicine [1-3]. For these applications, the highly fluorinated liquids are used in a purified form or as mixtures. The intended effect is created by the physicochemical characteristics themselves. The extraordinary behaviour of the fluorocarbon liquids (FCLs) requires specialised biocompatibility testing, adjusted to this class of components. 

FC-72 is a commercially available (3M) fluorocarbon liquid consisting mostly of isomers of C6Fi4 (bp 56°C). 

Water is frequently the choice for the liquid medium used in the test. However, the surface tension of water at 25X is 72 dyne/cm compared to 22 and 16 dynes/cm for ethanol and some fluorocarbons, respectively. Eq. (4-1) indicates that, for the same pore diameter to be determined, the required applied pressure needs to be only 1/3 or 1/4 approximately when an alcohol or a fluorocarbon liquid is used instead of water. Air or nitrogen is generally used as the gas medium. 

Suspension polymerisation in fluorocarbon liquids (method Ilb in Table 12.1)... 

The apparatus used for this study produced low transport rates for C02, as well as the previously discussed 02, with and without liquid membranes compared with developed oxygenators. The reason for this slow transport is the very large (approximately 0.4 cm) liquid membrane encapsulated bubbles contrasted with the small bubbles of developed oxygenator. A means is needed to produce small fluorocarbon liquid membranes in blood so that the rapid transport achieved in other liquid membrane applications using small diameter liquid membranes can be achieved for transferring gases to and from blood. 

Fig. 5.18 Innovative hydrodynamic principles of the CHEM-1 autoanalyser. (a) Capsule chemistry technology the fluorocarbon liquid film prevents contact between the segmented flow and the tube walls, (b) Mixing of two liquid segments Li and L2 separated by an air bubble in the vanish zone , (c) Special mixing loop. (Courtesy of Technicon).

Fluorocarbon and hydrocarbon modified PDMS surfaces are compared in Table 2. The contact angle data are obtained by the Good-Girifalco-Fowkes equation. It is striking that the hydrocarbon contact angle liquid gives better agreement with the JKR result for the hydrocarbon surface whereas the fluorocarbon liquid data better fit the fluorocarbon surface... 

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