DISCRETE STIMULATION OF SINGLE PROTOPLAST CELLS BY HIGHLY RESOLVED DRUG RELEASE

For the first time we present the discrete release of two individually addressable substances in the sub pl-range (10 pl) with a high spatial (< 50 µm) and temporal (< 100 µs) resolution for the stimulation of single cells, embedded in a thin-alginatelayer. This is ensured by dispensing a small droplet (O < 25 µm) with a diameter smaller or comparable to a single tobacco protoplast (O ≈ 30 µm). Furthermore, the pl-volume generates defined drug concentration at the target cell while the concentration gradient in the vicinity decreases drastically in time due to the 3dimensional diffusion and leads to extremely low background signals. The two channels of the presented dispenser allow for the discrete stimulation of single cells with one channel and the simultaneous labeling with the other one. This was proven by highly resolved labeling of a single tobacco protoplast with carboxyfluorescein diacetate.