D E M O N S T R A T E
Demonstrate
Biosensor Cells
Freeze Drying Protocol
In-Field Preparation of Cells
*Tubes should be on ice at all times unless centrifuging*
- Add 5 ml of sterile LB media and 5ul of chloramphenicol and ampicillin to a culture tube.
- Obtain the desired plate. Take 1-3 colonies from the biosensor cells’ plate with a sterilized inoculating loop. Stir vigorously to ensure colonies are dispensed into solution.
- Place culture tubes on a rack in the incubator. Set to shake and temperature to 36-38 C, and grow overnight.
- Centrifuge liquid culture and discard the supernatant. Resuspend the pellet in 5ml of Microbial Freeze Drying Buffer with tryptic soy broth.
- Aliquot 500ul of the suspension into sterile vials with stopper.
- Turn on the lyophilizer and start the condenser. Set the shelf to 4°C.
- Center the vials on the shelf. Either manually or with programmed controls, freeze the samples down to -40°C. This should take about 30-60 minutes, but it is very dependent upon the lyophilizer. If the rate of freezing can be controlled, a practical rate is to drop the temperature by 1°C per minute. The samples should be visually frozen.
- Let the samples sit at -40°C for 1 hour to complete freezing.
- Turn on the vacuum pump. Within 10-20 minutes, the vacuum should be under 200 millitorr (mtorr).
- After the vacuum is below 200 mtorr, increase the temperature of the shelf for primary drying. The temperature can be up to -15°C. Let continue overnight.
- For second drying, raise the shelf temperature to 20°C and dry for 2 hours.
- With the stoppering mechanism, pit the stoppers on the vacuum. Turn off vacuum.
- Store at 4°C in the dark.
In-Field Preparation of Cells
*Tubes should be on ice at all times unless centrifuging*
- Resuspend in 5 ml of LB agar. Incubate for two hour.
- Aliquot 1 ml of that liquid culture into 4 ml of sterile LB.
- Shake in an incubator overnight. If no incubator present, let sit at room temperature for a day and a half.
- Add the 5 ml liquid culture into 500 ml of sterile LB.
- Using the portable spectrophotometer, check the optical density every hour. Continue growing until the OD is 0.6.
- Pour cells into 50 ml conical tubes, on ice. Keep there for 30 minutes.
- Pipet up the bottom 1.5 ml in the tube and transfer to a microcentrifuge tube.
- With the 3D-fuge, centrifuge cells for 20 minutes, discard supernatant.
- Add 1.5 ml of ice-cold sterile into the microcentrifuge to resuspend. Add into empty 50 ml conical tube.
- Add another 11.5 ml of ice-cold sterile milliQ water to each conical tube, pipet up and down.
- Combine samples into 2 total conical tubes.
- Let sit on ice for 30 minutes. Take bottom 1.5 ml of each sample and transfer into a empty microcentrifuge tube.
- With 3D-fuge, centrifuge for 20 minutes, discard supernatant, and repeat steps 9 and 10.
- Let sit for 30 minutes on ice.
- Transfer bottom 1.5 ml into a microcentrifuge tube. Centrifuge for 20 minutes, discard supernatant, and add 1.5 ml of ice-cold 10% glycerol.
- Transfer the microcentrifuge into an empty conical tube. Add 23.5 ml of ice-cold 10% glycerol.
- Let sit for 30 minutes on ice. Repeat steps 15 and 16.
- Let sit for 30 minutes on ice. Take bottom 1.5 ml and transfer into a microcentrifuge tube. Centrifuge with 3D-fuge for 20 minutes.
- Resuspend in 1.5 ml of ice-cold 10% glycerol. Transfer into conical tube and add 2.5 ml of ice-cold 10% glycerol.
- Aliquot 1 ml into microcentrifuge tubes. Store in -80 freezer.