Recommended 3D Printer(s)
Stereolithography/optical
Recommended Printing Material
Scale At Given Print Units
Pre- and Postprocessing Instructions
1) Place tube fittings for inflow and outflow
- use a 10-32 hand tap to create threads in the holes for the fittings
- place 3 clear 10-32 plastic fittings into the inflow and outflow holes (e.g., 500890 Barbed Fitting, World Precision Instruments, WPI)
2) Attach Magnets on bottom corners (this will make the model mechanically stable when using a metal table)
- use 1/4 x 1/16 inch disc neodymium magnets (e.g.,D41-N52, K&J Magnetics)
- attach one to each of the bottom four corners of model using 2 ton epoxy (under chemical hood!)
- let cure overnight
3) Make the silicone base for the stomach chamber
- mix Sylgard Elastomer, 10 ml + 1 ml curing agent (184 Silicone Elastomer kit, Dow Corning)
- to make this coating a black color, add 50 mg charcoal per 11mL sylgard (C7606, Sigma-Aldrich) and mix
- fill the stomach compartment base with Sylgard mix up to the 5 mm line printed on the model
- let cure overnight
4) Install the recording wires
- cut two coated platinum-iridium wires each 6.5 cm (50 um diameter, A-M systems); additional wires can be placed for nerve stimulation
- remove ~0.5 cm of wire insulation using a flame; do not apply the flame near the 3D model
- insert the wires into the holes leaving a 1 cm length exposed in the recording compartment; the selection of holes depends on the length of the nerve; the wires should also be inserted into a corresponding hole in the back of the model taking care to remove any slack in the wire as it travels under the model
- coat the base of the recording chamber with silicone; we use Kwikcast (WPI) because it cures quickly (~3 min); this procedure will embed the electrodes, with only the recording tips exposed
- you can also use silicone on the underside of model to keep the wires in place and insulated
5) Attach the wires to connectors
- use plastic fittings to hold the connector pins, and glue to the back of the chamber using a cyanoacrylate adhesive (on the ledges; see image)
- solder miniature connector pins (520100, A-M Systems) to electrode wires
- trim excess wiring
5) Make the divider door
- using a plastic laboratory weigh boat, cut a 1cm x 1.2cm rectangles and also a notch at the bottom so the nerve will not get pinched as the door comes down
- apply vacuum grease around the edges of the door to seal the division