No. A series of experimental tests show that, when the diameter of needle electrodes was adjusted to 400 μm, the liquor tension between two adjacent electrodes could be eliminated. So there no cell adheres to needle electrodes during the electroporation. If the differences between the groups are just the parameters of electroporation, the matrix electrodes could be reused without any treatment. While the materials are different, such as the electroporation buffer, plasmid or cell. We suggest to cleaning the matrix electrodes with 75% alcohol before reuse.