Rodent Brain Microinjection Using a Quartz Microneedle

Take a quartz microneedle with customized holes, attached to a syringe filled with water, and connected to a micropump to control the delivery rate.

Take a secured, anesthetized rat with the exposed injection site.

Position the microneedle and place a paraffin film underneath. Put a drop of the injection solution on it.

Retract the water to create an air bubble, then lower the microneedle to draw the solution.

Allow a drop to form, ensuring clear passage.

Use a sharp needle to puncture the brain's membrane.

Insert the microneedle while set at a low delivery speed to prevent tissue fragment penetration into the needle.

Once positioned, go slightly deeper. Stop the delivery and raise it again to avoid backflow.

Start the delivery with increased speed. The holes in the needle ensure optimal distribution of the injected solution.

Allow sufficient time before withdrawing the needle to facilitate diffusion.

Cut a small piece of plastic paraffin film and place it on the skull. Using the 10-microliter pipette, make a drop of the solution to apply on the plastic paraffin film. Stop the pump. Slightly retrieve the pusher of the pump, and create a little air bubble in the capillary by gently pulling t