Open-ended coaxial exposure device for applying RF/microwave fields to very small biological preparations

An easily fabricated open-ended coaxial exposure device for applying radiofrequency/microwave energy to very small biological preparations is described. The device utilizes the fringing fields of a coaxial cable opening into a ground plane. Operation of the device is easily integrated into standard laboratory procedures in order to: observe a biological specimen; monitor temperature; regulate temperature, pH, and pO₂; and record cellular membrane potentials. The electromagnetic field configuration of the device leads to elimination of detectable interaction with microelectrodes. Measured patterns of electric field and specific absorption rate are given for a device built with quarter-inch semirigid coaxial cable and operating at 2450 MHz. Comparison is made to previous exposure devices for small biological preparations. The particular advantages of the open-ended coaxial exposure device over previous devices are the easy access to the preparation during exposure and the minimal, if any, coupling RF/microwave fields to microelectrodes used in electrophysiological studies