The influence of microinjection parameters on cell survival and procedure efficiency

Microinjection is a method commonly used to deliver various substances into cells. The procedure is performed on a widefield microscope stage using fine glass needle to penetrate the cell membrane. Microinjection can be carried out using a manual or semi-automatic mode. For commercially available equipment currently reported microinjection success rate and cell viability are relatively low (around 50% for both indicators). Here, for the first time, we systematically show how the microinjection effectiveness and cell viability are influenced by needle diameter and chosen microinjection mode. We found that manual mode entailed a higher injection rate, reducing cell viability at the same time. The reduction in needle diameter caused a significant increase in cell survival rate (from 43 to 73% for manual mode and from 58% to 86% for semi-automatic mode) and did not affect significantly the success rate. Our findings will help optimize this method in the context of cell biology research. • This study shows how to improve microinjection parameters, such as procedure efficiency and cell survival rate, for commercially available equipment. • Manual mode, in comparison with semi-automatic mode, results in higher microinjection efficiency, but lower cell survival rate. • The increase in micropipette diameter causes lower cell viability and a higher microinjection success rate.