Start by replacing the Ames media from the Petri dish that contained the mouse retina with a fresh supply of carbogenated Ames. Use a wide mouth transfer pipette to place a piece of dissected mouse retina onto a glass slide, ganglion cells side up. Remove the excess liquid with a delicate task wipe to flatten it.
If necessary, use a fine tip paintbrush to gently pull the retinal edges under a dissection microscope. Use forceps to place a dry piece of nitrocellulose membrane on the retina, adhering it to the ganglion cell side. Flip the retina over to lay the nitrocellulose on the glass slide, and place another dry membrane piece on the retina's photoreceptor side.
Now, wet the tip of the paintbrush with Ames media. Apply gentle downward pressure to the upper membrane to aid uniform adherence. Next, pin the lower membrane to the glass with one pair of forceps.
Then carefully use another pair to peel off the upper membrane in a slow, steady motion. Dispose of the upper membrane which contains the photoreceptors. Finally, return the lower membrane containing the inner retina to the carbogenated Ames media.