Summary

The Scratcher went through numerous iterations. The final form is in two pieces a handle that can be printed from any standard rigid resin. I used an Elegoo Mars Ultra 4 and 3DMaterials standard resin.

The tips must be printed from 3D materials, including Superflex resin. This ensures that tissue-treated plates do not get large scratches to the coating, which makes it hard to image later. The Superflex resin is soft enough not to damage the plate but still remove cells. They can be glued in place on the inserts on the handle but do not need to be. The holes are slightly oversized as fitting them exactly to the inserts caused cracking.

Printing as one piece or using harder resins for the tips causes scratches on the bottom of the plate.

The lid is meant to be laser cut from acrylic, the current width is designed for the scratcher to have minimal side-to-side movement while still being able to scratch, the width can be adjusted to create a second lid for marking the back of the plate with a pin around the scratch. When I have done this I have sized it to be 1mm wider than the width of whatever pen I am using contact point with the lid. This ensures a 1mm marked lane with a 0.5mm scratch in the middle, allowing consistent visualization.