TRANSMISSION phere had completely peeled from the sodium chloride crystal. Elemental analyses of the peeled film showed the presence of both oxygen and nitrogen. Another experiment was run in which the finished plasma polymer film was allowed to soak in an ethylene atmosphere in the reactor for 8 hours prior to being removed and exposed to the atmosphere. This film has not shown a tendency to peel. Looking at its spectra in figures 15 and 16, it is obvious that the hydroxyl and carbonyl regions have become more intense during observation for a period of 61 days. However, the new adsorption peak previously noted in figures 13 and 14 have not appeared. Additional experiments are underway to determine how the elemental composition of the polymer changes as a function of length of time that it is exposed to the atmosphere. These experiments are being run whereby the plasma films are being soaked or quenched with reactive and nonreactive gases, as well as being subject to thermal treatments. Studies are also being conducted to follow the decay, of the active species by means of electron spin resonance spectroscopy over a similar period of time. 100 80 60 1000 6. Summary Plasma polymerization constitutes a unique technique for forming thin polymer films on a variety of substrates. In most instances the polymers formed by these techniques are more uniform and more stable than conventional polymer films. There is a great deal to be investigated concerning the mechanism by which these polymers are formed. In addition, the kinetic and thermodynamic variables must be understood before one can hope to deposit adherent films on substrates intended for biomedical applications. Preliminary results have indicated that these polymers are potential candidates for biomedical purposes. We wish to acknowledge the advice and assistance of Dr. Theodore Wydeven, NASA Laboratories, Moffett Field, California. We also wish to acknowledge The National Science Foundation who partially funded this work. 7. References [1] McTaggart, F. K., Plasma Chemistry in Electrical Discharges, (Elsevier Publishing Company, New York, N.Y., 1967). [2] de Wilde, P., Ber. 7, 4658 (1874). [3] Thenard, A., Comp. Rend. 78, 219 (1874). [4] Coats, A. D., U.S. Dept. Comm. Office Tech. Serv. A. D., 419-618 (1962). [5] Tomkinson, D. M., Galvin, J. P., and Pritchard, H. O., Free radical dissociation of halogenated aromatics in a plasma, J. Phys. Chem. 68, 541 (1964). [6] Ogurtsoua, N. N., and Podmosleineskll, J., Zh. Prikl. Spektrosk. 8, 1043 (1968). [7] Sacher, E., J. Polym. Sci. Part A, 6, 1813 (1968). [8] Sakurada, I., Macromolecules 1, 265 (1968). [9] Bashara, N. M., and Doyty, C. T., Appl. Phys. 35, 3498 (1964). [10] Kronick, P. L., and Jesch, K. F., J. Polym. Sci. Part A, 7, 767 (1963). [11] Bradley, A., and Hammes, J. P., J. Electrochem. Soc. 110, 15 (1963). [12] Hanson, R. H., Pascale, J. V., de Benedictis, T., and Rentzepis, P. M., J. Polym. Sci. Part A 3, 2205 (1965). [13] Hanson, R. H., and Schonhorn, H., Polym. Letters 4, 203 (1966). [14] Weininger, Nature 186, 546 (1960). [15] Weininger, J. L., The reaction of active nitrogen with polyolefins, J. Phys. Chem. 65, 941 (1961). [16] Hollahan, J. R., Stafford, B. B., Balk, R. D., and Payne, S. T., J. Appl. Polym. Sci. 13, 807 (1969). [17] Bazzarree, D. F., and Lin, L. J., Quarterly report to Naval Ordnance Systems Command, No. N00017-69-C-4424, (1969). [18] Shaw, W., Personal Communication, Western Electric Co., Kansas City, Mo., (1970). [19] Ozawa, P. J., IEEE Trans. PMP-5, 112 (1969). [20] Mearns, A. M., Thin solid films 3, 201 (1969). [21] Goodman, J., J. Polym. Sci. 44, 552 (1960). [22] Williams, T., and Hayes, M. W., Nature 209, 769 (1966). [23] Denaro, A. R., Owens, P. A., and Crawshaw, A., Eur. Polym. J. 4, 93 (1968). [24] Venugopalan, M., Reactions Under Plasma Conditions, (Two Volumes), (Wiley-Interscience, New York, N.Y., 1971). [25] Nasser, E., Fundamentals of Gaseous Ionization and Plasma Electronics, (Wiley-Interscience, New York, N.Y., 1971). [26] Gould, R. F. (Ed.), Chemical reactions in electrical discharges, (American Chemical Society, Washington, D.C., 1969). [27] Kolotyrkin, V. M., Gilman, A. B., and Tsapuk, A. K., Russian Chem. Rev. 36, No. 8, 579 (1967). [28] Suhr, H., Naturwissenschaften 55, 168 (1968). [29] Swift, F., Sung, R. L., Doyle, J., and Stille, J. K., J. Org. Chem. 30, 3114 (1965). [30] Stille, J. K., Sung, R. L., and Vander Kool, J., J. Org. Chem. 30, 3116 (1965). [31] Stille, J. K., and Rix, C. E., J. Org. Chem. 31, 1591 (1966). [32] Lawton, E. L., J. Polym. Sci. A-1, 10, 1857 (1972). [33] Taki, K., Bull. Chem. Soc. of Japan 43, 1574 (1970). [34] Taki, K., Bull. Chem. Soc. of Japan 43, 1578 (1970). [35] Taki, K., Bull. Chem. Soc. of Japan 43, 1580 (1970). [36] Simionescu, C., Asandei, N., Denes, F., Sandulouici, M., and Popa, G., Eur. Polym. J. 5, 427 (1969). [37] Yasuda, H., and Lamaze, C. E., J. Appl. Polym. Sci. 15, 2277 (1971). [38] Westwood, A. R., Eur. Polym. J. 7, 363 (1971). [41] Thompson, L. F., and Mayhan, K. G., J. Appl. Polym. Sci. 16, 2291 (1972). [42] Thompson, L. F., and Mayhan, K. G., J. Appl. Polym. Sci. 16, 2317 (1972). [43] Brown, K. C., and Copsey, M. J., Eur. Polym. J. 8, 129 (1972). [44] Kronick, P. L., Jesch, K. F., and Bloor, J. E., J. Polym. Sci. A-1, 7, 767 (1969). NATIONAL BUREAU OF STANDARDS SPECIAL PUBLICATION 415, Biomaterials, Proceedings of a Symposium held in conjunction with the Ninth Annual Meeting of the Association for the Advancement of Medical Instrumentation, New Orleans, La., April 19-20, 1974 Issued May 1975). Plasma-Formed Polymers for Biomedical Applications Part II. Biocompatibility and Applications* A. W. Hahn John M. Dalton Research Center K. G. Mayhan Graduate Center for Materials Research and Chemical Engineering Department and J. R. Easley and C. W. Sanders John M. Dalton Research Center University of Missouri, Columbia, Mo. 65201 Different polymer films generated by rf plasma techniques and deposited on glasses of varying chemical composition, on implant alloys, and on formed prosthetic polymers have been implanted in New Zealand white rabbits and various canine species and have shown minimum tissue reactions after periods of time up to six months. It has further been found that the substrates upon which the plasma polymers are formed are more detrimental to cell cultures than the polymers themselves. These findings, along with other implant work, indicate that plasma-formed polymers will play a definite role as biocompatible materials in the future. Key words: Biocompatibility; inflammatory response; plasma polymers; tissue reaction. 1. Introduction In Part I of this joint paper [1],1 Mayhan et al. have reviewed the fundamentals of the synthesis and deposition of the plasma polymerized films on various surfaces. Our studies were undertaken to explore the compatibility of these polymers with biological tissues and some selected applications to the fields of biology and medicine. 2. Compatibility Studies Our investigation of compatibility with biological tissues has taken two forms. First, the polymers, coated on a suitable substrate, were exposed to tissue culture. To date we have conducted these tissue culture exposures for the following plasma polymerized materials: polyvinyl chloride, polyethylene, polyallene, polytetrafluroethylene, poly chlortrifluroethylene, polystyrene, polyacyrilonitrile, and polyvinyl fluoride. The procedure used for studying these materials was to obtain various thicknesses of coatings on both glass and commercially available polystyrene cover slips especially made for tissue culture. These 5×10 mm slips were coated, on one side only, under varying reactor conditions. The materials were then brought to our laboratory at University of Missouri-Columbia where the glass cover slips were exposed to autoclaving at standard conditions for sterilization and the polystyrene cover slips were exposed to ethylene oxide sterilization under appropriate conditions. Control slides of both glass and polystyrene were also sterilized under identical conditions. Each of the study materials was then placed in Leighton tubes which had been previously sterilized, and 5 ml of cells and a standard tissue culture media were added to each tube. The cells used were the HEP-2 cell line which has been well developed and standardized for tissue culture studies. Approximately 106 cells were added to each tube. These were then placed in a carbon dioxide incubator at 37 °C and 6. Summary Plasma polymerization constitutes a unique technique for forming thin polymer films on a variety of substrates. In most instances the polymers formed by these techniques are more uniform and more stable than conventional polymer films. There is a great deal to be investigated concerning the mechanism by which these polymers are formed. In addition, the kinetic and thermodynamic variables must be understood before one can hope to deposit adherent films on substrates intended for biomedical applications. Preliminary results have indicated that these polymers are potential candidates for biomedical purposes. We wish to acknowledge the advice and assistance of Dr. Theodore Wydeven, NASA Laboratories, Moffett Field, California. We also wish to acknowledge The National Science Foundation who partially funded this work. 7. References [1] McTaggart, F. K., Plasma Chemistry in Electrical Discharges, (Elsevier Publishing Company, New York, N.Y., 1967). [2] de Wilde, P., Ber. 7, 4658 (1874). [3] Thenard, A., Comp. Rend. 78, 219 (1874). [4] Coats, A. D., U.S. Dept. Comm. Office Tech. Serv. A. D., 419-618 (1962). [5] Tomkinson, D. M., Galvin, J. P., and Pritchard, H. O., Free radical dissociation of halogenated aromatics in a plasma, J. Phys. Chem. 68, 541 (1964). [6] Ogurtsoua, N. N., and Podmosleineskll, J., Zh. Prikl. Spektrosk. 8, 1043 (1968). [7] Sacher, E., J. Polym. Sci. Part A, 6, 1813 (1968). [8] Sakurada, I., Macromolecules 1, 265 (1968). [9] Bashara, N. M., and Doyty, C. T., Appl. Phys. 35, 3498 (1964). [10] Kronick, P. L., and Jesch, K. F., J. Polym. Sci. Part A, 7, 767 (1963). [11] Bradley, A., and Hammes, J. P., J. Electrochem. Soc. 110, 15 (1963). [12] Hanson, R. H., Pascale, J. V., de Benedictis, T., and Rentzepis, P. M., J. Polym. Sci. Part A 3, 2205 (1965). [13] Hanson, R. H., and Schonhorn, H., Polym. Letters 4, 203 (1966). [14] Weininger, Nature 186, 546 (1960). [15] Weininger, J. L., The reaction of active nitrogen with polyolefins, J. Phys. Chem. 65, 941 (1961). [16] Hollahan, J. R., Stafford, B. B., Balk, R. DaiS. T., J. Appl. Polym. Sci. 13, 807 (1969) [17] Bazzarree, D. F., and Lin, L. J.. Quarterly repeti Ordnance Systems Command, No. N00017 (1969). [18] Shaw, W., Personal Communication, Western Eørt. Kansas City, Mo., (1970). [19] Ozawa, P. J., IEEE Trans. PMP-5, 112 (1969 [24] Venugopalan, M., Reactions Under Plasma [25] Nasser, E., Fundamentals of Gaseous lonization anti .Electronics, (Wiley-Interscience, New York. V [26] Gould, R. F. (Ed.), Chemical reactions in eiecte a în charges, (American Chemical Society, Washing 1969). [27] Kolotyrkin, V. M., Gilman, A. B., and Tsapuk, AK Chem. Rev. 36, No. 8. 579 (1967). [28] Suhr, H., Naturwissenschaften 55, 168-198 [29] Swift, F., Sung, R. L.. Doyle, J., and Stille, JA, ". Chem. 30, 3114 (1965). [30] Stille, J. K., Sung, R. L., and Vander Kool, J.J. Og 30, 3116 (1965). [31] Stille, J. K., and Rix, C. E., J. Org. Chem. 31,. [37] Yasuda, H., and Lamaze, C. E., J. Appl. Po NATIONAL BUREAU OF STANDARDS SPECIAL PUBLICATION 415, Biomaterials, Proceedings of a Symposium held in conjunction with the Ninth Annual Meeting of the Association for the Advancement of Medical Instrumentation, New Orleans, La., April 19-20, 1974 (Issued May 1975). Plasma-Formed Polymers for Biomedical Applications Part II. Biocompatibility and Applications* A. W. Hahn John M. Dalton Research Center K. G. Mayhan Graduate Center for Materials Research and Chemical Engineering Department and J. R. Easley and C. W. Sanders John M. Dalton Research Center University of Missouri, Columbia, Mo. 65201 Different polymer films generated by rf plasma techniques and deposited on glasses of varying chemical composition, on implant alloys, and on formed prosthetic polymers have been implanted in New Zealand white rabbits and various canine species and have shown minimum tissue reactions after periods of time up to six months. It has further been found that the substrates upon which the plasma polymers are formed are more detrimental to cell cultures than the polymers themselves. These findings, along with other implant work, indicate that plasma-formed polymers will play a definite role as biocompatible materials in the future. Key words: Biocompatibility; inflammatory response; plasma polymers; tissue reaction. 1. Introduction In Part I of this joint paper [1],1 Mayhan et al. have reviewed the fundamentals of the synthesis and deposition of the plasma polymerized films on various surfaces. Our studies were undertaken to explore the compatibility of these polymers with biological tissues and some selected applications to the fields of biology and medicine. 2. Compatibility Studies Our investigation of compatibility with biological tissues has taken two forms. First, the polymers, coated on a suitable substrate, were exposed to tissue culture. To date we have conducted these tissue culture exposures for the following plasma polymerized materials: polyvinyl chloride, polyethylene, polyallene, polytetrafluroethylene, poly Supported in part by grants from the National Science Foundation (#NSF GK 38957) and the National Aeronautics and Space Administration (#NASA NGR 26004-099). 'Figures in brackets indicate the literature references at the end of the paper. chlortrifluroethylene, polystyrene, polyacyrilonitrile, and polyvinyl fluoride. The procedure used for studying these materials was to obtain various thicknesses of coatings on both glass and commercially available polystyrene cover slips especially made for tissue culture. These 5 × 10 mm slips were coated, on one side only, under varying reactor conditions. The materials were then brought to our laboratory at University of Missouri-Columbia where the glass cover slips were exposed to autoclaving at standard conditions for sterilization and the polystyrene cover slips were exposed to ethylene oxide sterilization under appropriate conditions. Control slides of both glass and polystyrene were also sterilized under identical conditions. Each of the study materials was then placed in Leighton tubes which had been previously sterilized, and 5 ml of cells and a standard tissue culture media were added to each tube. The cells used were the HEP-2 cell line which has been well developed and standardized for tissue culture studies. Approximately 106 cells were added to each tube. These were then placed in a carbon dioxide incubator at 37 °C and |