To attach the methyl methacrylate or MMA coated CVD graphene to the grids, use the previously prepared grid-sized coated graphene squares kept in a beaker containing molecular grade water. Using negative action tweezers. Gently dip a grid vertically into the water with the carbon side facing a floating MMA graphene square.
Once in contact with the square, carefully remove the grid from the water while ensuring the square fully adheres to the carbon side of the grid. Place the grids on a clean cover slip with the MMA graphene side facing up and allow the grids to air-dry for one to two minutes. Using flat tip tweezers, transfer the cover slip with the grids to a hot plate set at 130 degrees Celsius.
Incubate the grids after covering them with the top of a glass Petri dish for 20 minutes. Next, for washing MMA with acetone, transfer the entire cover slip into a Petri dish filled with 15 milliliters of acetone and incubate for 30 minutes. Then, using a clean glass serological pipette, transfer the acetone to a waste container.
With another clean glass serological pipette, add 15 milliliters of fresh acetone to the Petri dish and incubate for 30 minutes. After three acetone washes, remove the acetone. And using a clean glass serological pipette, replace it with 15 milliliters of isopropanol.
Then using tweezers, carefully remove the grids for isopropanol to air-dry them on a clean cover slip. Next place the cover slip with graphene-coated grids on a hot plate set to 100 degrees Celsius for 10 minutes to evaporate the residual organics. Using reverse action tweezers, gently place the grids into a clean illumination area of a UV ozone cleaner with the graphene-coated side facing up.
Slide the illumination area closed and turn the machine on. Set the time dial to the designated treatment time to start UV ozone treating the grids. Finally, proceed to plunge a cryo-electron microscopy sample on the treated grids.
