Opto-electrostatic micro-manipulation of protoplasts and fine particles

Optoelectrostatic micromanipulation utilizing the electrostatic force in combination with the optical pressure of a focused laser beam has been used for handling of plant protoplasts and for microinjection of fine latex particles into plant protoplasts. Cabbage or carrot protoplasts were used. Cabbage protoplasts could be moved by the optical pressure at 10 to 80 mu m/s. Using a parallel electrode system, the protoplasts were connected to form a pearl chain. An argon ion laser was then focused on one protoplast at the tip of a pearl chain. All the protoplasts were trapped at the electrode by the dielectrophoretic force. and only the protoplast irradiated by the laser could be separated selectively. Microinjection of 0.2-0.4 mu m latex particles to the cabbages or carrot protoplasts was made using optoelectrostatic micromanipulation. The latex particles were transported to the surface of the protoplasts inside a parallel-plate electrode system. Then a pulsed high voltage was applied several times to inject one latex particle attached on the surface of the protoplast. The injected latex particle could be manipulated inside the protoplast by the optical pressure. The experimental apparatus and the results are reported.<>