This repo holds the 3D files for optrodes holder used in my poster (optrode_holder_flicre_v2.ipt), and also in the lab to give another example of use (optrode_holder_maelle.ipt).
This holder was inspired by the UCLA miniscope 3D printed lens holder that is available to print here (if anybody can put their hand on an actual reference, it would be mch appreciated).
Ajusted for 1.2mm external diameter optrodes
Optrodes are aligned A/P
Optrodes are 2.3mm apart M/L
Optrodes D/V is ajusted when mounting them on the holder.
I use an Elegoo Mars 3 resin printer for these. First layer to be printed is on the large rectangular holder part. Here are the printing parameters:
Layer height: 0.050mm
Bottom layer count: 4
Exposure time: 3s
Bottom exposure time: 10s
Waiting mode during printing: Resting
Rest time before lift: 0.000s
Rest time after lift: 0.000s
Rest time after retract: 0.500s
Bottom lift distance: 5s
Lifting distance: 5mm
Bottom lift speed: 60mm/min
Lifting speed: 80mm/min
Bottom retract speed: 210mm/min
Retract speed: 210mm/min
First build the optrodes (here, from 1.2 external diameter ferrules (Thorlabs CFLC 230, 230um ID) and optic fiber but you can adapt the 3D model to fit yours).
Secondly, prepare the optrode holder by running a 18G needle (or whatever is the same diameter as your optrodes) into the holes to clear a path for the optrodes as the 3D printing process is not always perfect.
Thirdly, insert the optrodes in the holder holes. In my case, they are at the same depth so I only worry about leaving as much clearance as possible on top to allow for dental cement to cover the holder and still have enough room to plug the fibers to the optrodes when doing behaviors. Lastly, glue the optrodes in place. I use cyanoacrylate-based glue, but I assume any epoxy would do just fine. I just prefer fast curing to be certain the optrodes won't move D/V while curing.
Install the holder to the stereotax, paying close attention to the A/P lineup.
Take bregma with both optrodes to make sure they are aligned well, and at the same height. If optrodes are not at the same depth, you can probably only take bregma with one of them (depending on how far away they are, you might still be able to check both).
Once implanted, cover the "optrode" part of the holder with cement. The plastic surrounding the optrodes will stay with them inside of the animal (Bonus, it really helps the cement to hold on to the optrodes). Once the cement has set, just drill out the smaller part of the holder (it's made for this reason) and finish covering up with cement.
Feel free to use these 3D models as basis to make your own, or even use those directly. If you have any suggestions, printing tips or ideas to better the design, please submit an issue on this repo!
Clément Pouget - C4Team @ ESPCI Paris