Biological ion implantation facility

Summary form only given. Ion beam bombardment for the surface modification of biomedical substrates is experiencing rapid growth as a tool for improving and controlling the biocompatibility of materials in a number of ways. Ion bombardment of living biological tissue of various kinds is a related research field with some potentially far-reaching applications. For example, in recent work (Anuntalabhochai et al, 2001) we have demonstrated ion beam induced DNA transfer into living E. coli cells. A critical part of the experimental procedure has to do with the fact that the object being bombarded is live, and for most experimental purposes is required to survive both the vacuum exposure and the ion beam bombardment. This in turn places some constraints on the ion beam bombardment facility and the experimental procedures that are not normally of concern in the usual case of ion implantation into non-living materials. Here we describe an ion beam facility that has been designed and made at Chiang Mai University for specific application for the bombardment of living sample materials. The experimental part of the beam line is vertical for convenient manipulation of biological samples. The target chamber can be pumped down quickly for maintaining sample viability. Ion species available include both gaseous and solid species; beam energy is variable up to 30 keV, and beam current up to hundreds of microamperes can be achieved. The application terminal is to be equipped with a beam sweeper, an AFM (atomic force microscope) load-lock chamber for in situ surface measurements, and a TOF-SIMS (time-of-flight secondary ion mass spectrometer) system for surface sputtering studies. The beam emittance and optics have been characterized. The facility is located within a bio-clean room. Here we outline some of the unique design considerations addressed, and summarize the device performance.