Focal macromolecule delivery in neuronal tissue using simultaneous pressure ejection and local electroporation

Area of Science:

• Cell biology
• Neuroscience
• Biotechnology

Background:

• Electroporation facilitates macromolecule entry into cells by creating transient plasma membrane pores.
• Conventional electroporation methods often lack spatial precision, limiting targeted delivery.
• Introducing impermeable molecules into specific cellular regions, like neurons, remains challenging.

Purpose of the Study:

• To develop a novel device for localized electroporation combined with pressure ejection.
• To improve the precision and reduce the damage associated with macromolecule delivery.
• To demonstrate the utility of this technique for cell transfection and neural circuit analysis.

Main Methods:

• A double-barreled glass micropipette was engineered for simultaneous local pressure ejection and electroporation.
• The device was tested on cultured HEK293 cells and ex vivo brain slices (cerebellar and hippocampal).
• Propidium iodide, dextran amine, and EGFP plasmids were used as model macromolecules.

Main Results:

• The technique achieved precise delivery of macromolecules within 100-200 micrometer areas.
• Local electroporation, when combined with pressure ejection, enabled efficient EGFP plasmid transfection.
• This method proved less damaging than global electroporation and facilitated axonal tract tracing in brainstem slices.

Conclusions:

• The developed local electroporation device offers enhanced targeting and reduced cellular damage.
• This technique is effective for transfecting cells and labeling specific neuronal populations.
• It provides a valuable tool for studying synaptic connectivity and live axonal tracing in neural tissues.