Patterned Adhesion of Cells
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1020-GG05-01
Patterned Adhesion of Cells Robert Lee Zimmerman1, Ismet Gurhan2, and Daryush ILA1 1 Center for Irradiation of Materials, Alabama A&M University, 3900 Meridian Street, Normal, AL, 35762 2 Faculty of Engineering, Ege University, Izmir, Turkey ABSTRACT: It is well known that silver deposition avoids bacterial growth and inhibits the natural process of attachment of connective tissue to biocompatible materials in vivo. We have completed a five year investigation of the precise spatial control of cell growth on glassy polymeric carbon implanted with silver using ion beam techniques, and the persistence of the inhibitory effect on cell growth. Long term inhibition of cell growth on GPC is a desirable improvement on current cardiac implants and other biocompatible materials placed in the blood stream. We have used implanted silver ions near the surface of GPC to completely inhibit cell attachment and adhesion. Cells attach and strongly adhere to areas close to the silver implanted surfaces. Patterned ion implantation permits precise control of tissue growth on GPC and other biocompatible substrates. Cell growth limited to micrometric patterns on a substrate may be useful for in vitro studies of associated biological processes in an otherwise identical environment. The patterned inhibition of cell attachment persists for periods of time significant relative to typical implant lifetimes. INTRODUCTION: Glassy Polymeric Carbon (GPC), like other forms of pure carbon, is completely biocompatible. The inert chemical nature of GPC makes it useful for medical implants. Many living cells need surfaces, such as bone and collagen, to develop properly and the surface of GPC seems just as acceptable to those cells as the natural substrates. When rapid and complete cell attachment is desirable, for sub coetaneous electrodes or temporary fluid delivery tubes, for example, GPC serves perfectly without surface treatment. However, for many applications the spatial control of cell attachment is essential [1]. The strength, durability and low density make GPC a favored material for the manufacture of artificial heart valves. Connective tissue cells naturally attach and encapsulate the implant, a desirable consequence of acceptance of the implant. However, the low cell adhesion to the glassy surfaces of the moving parts of the GPC valve has the potential [2] of creating an embolism if tissue is released into the blood stream. For the GPC heart valve, and for many applications in biology, our goal is to control the locations that cells do and do not attach. Oxygen ion bombardment of GPC has been used [3, 4] to increase the surface roughness and enhance cell adhesion, and implanted silver ions near the surface of GPC inhibit cell attachment and adhesion [5, 6]. Both enhancement and inhibition of cell attachment to GPC are desirable modifications of GPC for particular medical applications.
We have used ion bombardment and ion implantation to provide physical and chemical signals at the GPC surfaces that either increases cell adhes
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