To begin the anterior fixation of the induced pluripotent stem cell-derived retinal organoids or ROs. Using a pipette, gently move one of the cultured ROs from the Petri dish to a 1.5-milliliter microcentrifuge tube. With the help of a pipette, remove the culture medium from the microcentrifuge tube and add 1.5 milliliters of 2%paraformaldehyde, 2%glutaraldehyde fixative.
After the ROs are fixed, remove the paraformaldehyde-glutaraldehyde fixative before proceeding to wash the organoids. Gently suspend the organoids in the microcentrifuge tube by adding 1 milliliter of 0.01 molar PBS to ensure complete washing. Then pipette out any remaining PBS and replace it with approximately 150 microliters of 1%osmic acid until the tissue blocks are submerged.
Place the microcentrifuge tube in a dark box.
