Sylgard-Coated Coverslips and Petri Dishes

1. Spread coverslips in many large Petri dishes (diameter of 100 mm or more) so that they are not touching each other, but the whole dish is covered.

2. Prepare the Sylgard following the manufacturer's instructions (basically by mixing the two components at a 10:1 ratio in a 50-mL Falcon tube) and mix well.

3. Fill a 1-mL syringe with the Sylgard mixture. Release a single drop on top of each coverslip.

• One drop is enough; do not add more or it will go over the coverslips, joining them all together and creating an unusable art installation.

4. Place Petri dishes flat in an incubator for a few hours or overnight at ∼50°C until the Sylgard is hard.

• Sylgard will remain liquid if stored at −20°C for some time (months); keep leftover material at −20°C for future preparation of Sylgard-covered coverslips.

5. Prepare the Sylgard following the manufacturer's instructions (basically by mixing the two components at a 10:1 ratio in a 50-mL Falcon tube) and mix well.

6. Pour Sylgard into a 35-mm Petri dish to cover its surface completely with a thick layer (approximately half its height).

7. Place the Petri dish flat in an incubator overnight at ∼50°C until the Sylgard is hard.