You should keep the circuit at balance before injecting which means you should use a current which has oposite polarity as to your dye. Later for releasing the dye you must repel it via applying a congruent polarity.

Thank you very much! Do I understand it right, I first need to impale the cell while still have the opposite polarity and then switch the polarity once in the cell? On the other hand, if my dye is membrane impermeable, can't I use congruent polarity all way long. It probably would not hurt if it's released a bit in the bath.

I have only done it extracellularly and in vivo, but I think the principle is the same.

Dear Olga,

If your dye is positively charged then you should use depolarizing (positive current) pulses to push the dye from your electrode into the cytoplasm. If your dye is negatively charged then you should use hyperpolarizing (negative current) pulses to dye-fill the cell. I have used Neurobiotin, biocytin, Lucifer Yellow, Horse Radish Peroxidase and Alexa dyes in my studies. For an example, please have a look at my listed publication below.

Best wishes,

Refik

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