| 1. | Place slides in slide racks. Place racks in chambers. |
| 2. | Prepare CLEANING SOLUTION: |
| Dissolve 70 g NaOH in 280 mL ddH2O. |
| Add 420 mL 95% ethanol. Total volume is 700 mL (= 2 X 350 mL); stir until completely mixed. |
| If solution remains cloudy, add ddH2O until clear. |
| 3. | Pour solution into chambers with slides; cover chambers with glass lids. Mix on orbital shaker for 2 hr. |
| Once slides are clean, they should be exposed to air as little as possible. Dust particles will interfere with coating and printing. |
| 4. | Quickly transfer racks to fresh chambers filled with ddH2O. Rinse vigorously by plunging racks up and down. |
| Repeat rinses 4X with fresh ddH2O each time. It is critical to remove all traces of NaOH-ethanol. |
| 5. | Prepare POLYLYSINE SOLUTION: |
| 70 mL poly-L-lysine + 70 mL tissue culture PBS in 560 mL water. |
| Use plastic graduated cylinder and beaker. |
| 6. | Transfer slides to polylysine solution and shake 15 min. - 1 hr. |
| 7. | Transfer rack to fresh chambers filled with ddH2O. Plunge up and down 5X to rinse. |
| 8. | Centrifuge slides on microtiter plate carriers (place paper towels below rack to absorb liquid) for 5 min. @ 500 rpm. |
| Transfer slide racks to empty chambers with covers for transport to vacuum oven. |
| 9. | Dry slide racks in 45C vacuum oven for 10 min. (Vacuum is optional.) |
| 10. | Store slides in closed slide box (plastic only, without rubber mat bottom) | 11. | BEFORE PRINTING ARRAYS: | | Check that polylysine coating is not opaque. | | Test print, hyb and scan sample slides to determine slide batch quality. | |