A novel device for intracellular microinjection was designed to integrate controlled pressure microinjection and electrical microinjection (iontophoresis) with membrane potential recording and a limited capacity for turgor measurement. The validity of the device was verified by microinjection of a mixture of the fluorescent probes, Texas Red sulfonyl chloride and 10 kDa-LYCH-dextran conjugate, into epidermal cells of variegated Coleus blumei leaves. Continuous monitoring of the fluorochrome movement by confocal laser scanning microscopy evidenced that the novel device succeeded in differential micro-injection of the fluorescent probes by pressure and iontophoresis. The multifunctionality of the microinjection system was further demonstrated by showing that both microinjection methods functioned in parallel with cellular membrane potential measurements in Vicia faba stem tissue. Advantages and prospective applications of the integrated microinjection/membrane potential measurement system are briefly discussed.
lontophoresis - intracellular microinjection - membrane potential measurement - pressure injection - pressure probe - turgor measurement
