Figure 3.

Digestion and expansion of the gel following removal from the gelation chamber

(A). When the top coverslip is removed from the Gelation Chamber following polymerization, the gel usually remains attached to it (A). Place the coverslip gel side-up in a 35 mm dish. If the gel stays on the original coverslip, transfer that coverslip gel side-up to a 35 mm dish. Once the digestion buffer is added, the lid should be secured to the dish using parafilm to prevent evaporation and the dish transferred to a humidified chamber containing a damp tissue. Seal the chamber and place it in a water bath set to 50°C (B). Close the lid and leave 18–20 h. Transfer the digested gel to a 10 cm Petri dish (C). At this point we normally observe some initial expansion (D). Add ddH₂O with Hoechst dye to start expansion/DNA staining. After ~1 h (and at least 3 changes of ddH₂O), the gel will be significantly larger than the original coverslip, which is shown on top of it for comparison (E).