Table 2.
An overview of the checkpoints used to assess the outcome of different stages in the BBB chips timeline. These checkpoints include PDMS bonding, media perfusion, cell attachment and the formation of a confluent monolayer. Common and suspected failure modes are also described.
| Description | Common and Suspected Failure Modes | ||
|---|---|---|---|
| Sample size of chips between checkpoints 1–2 | 17 | ||
| Checkpoint 1 | Successful PDMS-PDMS bonding based on complete transparency of PDMS pieces and manual leak test | 100% | N/A |
| Checkpoint 2 | Viable chips at the end of the experiment | 88% | Tubing coming undone from needle on syringe that is dispensing media. |
| Sample size of chips between checkpoints 3–4 | 8 | ||
| Checkpoint 3 | Chips with cell attachment | 88% | Cell detachment due to uneven ECM coating, air bubbles in the channel, or insufficient media supply. |
| Checkpoint 4 | Chips with a confluent monolayer | 57% | Washing and fixing steps and disassembly of chips caused cells to lift before mounting membranes onto glass slides. Cell detachment due to uneven ECM coating. |