Photocatalyst coated capillary increases efficiency of membrane penetration process of microinjection

The microinjection process has been improved by pinpoint use of the photosensitizing (PS) effect to degenerate cell membranes prior to injection. This avoids mechanical perforation of the membrane when the pipette tip makes contact with the cell. Titanium oxide was used as a photocatalytic coating for capillaries in this experiment. It catalyzes reactive oxygen species under UV light and degenerates cell membranes by oxidation. This process was evaluated by injecting water-soluble fluorescent Lucifer Yellow (LY) CH dye into rat pheochromocytoma PC12 cells. The injections were automated by a programmable motorized manipulator. The success rate was 57% for injections done using an 180 nm-thick titanium-oxide coated capillary under UV light and 43% for a capillary with a costing 120 nm thick. Without UV light, the success rates dropped to 20% for the capillary with the 180 nm coating, and 6% for the capillary with the 120 nm coating. These results suggest that using the PS-effect with microinjections increases injection-success rates and reduces the rate of cell injury caused by injection.