2D Detection of IPTG and HSL

Chip Production

Cell Preparation

1. over night culture of sensor cells (50 mL in a 250 mL flask with) max. 16 h
2. centrifuge all 50 mL by 3000 g for 10 min at RT (21 °C).
3. discard the supernatant
4. re-suspend the pellet in 1 mL tempered (~21 °C) LB-medium .

Agar Preparation

1. autoclave 50 mL medium with 1.5 % (w/v) agarose (has to be multiplied with the number of chips prepared).
2. cool it down to 45 °C in a water bath.

Chip Preparation

1. mix the cooled medium with the cells by inverting gently.
2. pour it in the chip form, avoiding bubble formation (!).
3. wait for approximately 20 min until the agar has solidified.
4. cut out the chips with a scalpel.
5. put two chips into a labeled petri dish and store additional 4 chips in labeled petri dishs in the refrigerator.
6. incubate two chips for 1 h at 37 °C prior to induction.

Sensor-chip manufacturing Scheme illustrating the work flow during chip production.

Measurement of Fluorescence