Would greatly appreciate any insight as to whether it is possible to use a Microelectrode Puller (specifically, the PUL-1000 y WPI) to produce needles with a total shaft length of less than 50 mm. The micropipette loading tips we currently have available are approximately 40–50 mm in length, and the rather viscous solution we aim to inject must be backfilled at the base of the needle's taper.

Our ability to proceed with experimentation is constrained by the limited availability of longer loading tips (e.g., ~100 mm), which no longer appear to be manufactured or readily accessible.

We would greatly appreciate any guidance/advice.