To begin, add pure epoxy resin to the groove of the embedding mold up to two thirds of its volume. Use a toothpick to pick retinal organoids and transfer them into the embedding mold, equipped with pure epoxy resin. Then fill the groove with pure epoxy resin until it slightly protrudes or bulges.
Adjust the position of the organoids at both ends of the embedding mold for directional embedding. Install the embedding block into the sample mounting stand and screw down the bolt with an L screwdriver. Then install glass knives on the knife stand and tighten the nut manually.
Trim away the excess resin until the desired area is exposed. Fill the trough of the glass knife with water. Using a semi-thin microtome, cut semi-thin slices to a thickness of one micron, and lay them on a microscope slide with a needle.
Add 50 microliters of 1%toluidine blue to dye the semi-thin slices, and incubate for one minute at 95 degrees celsius on the heating plate. Rinse with distill water for two minutes. Use a 20x ordinary optical microscope to observe the structure of the sections.
