Depositing Lipid Monolayer on Mica

Depositing Lipid Monolayer on Mica

Cleaning the Trough Protocol

1.  While wearing poly gloves, remove the plastic covers from the trough.

2.  Remove the trough dipping mechanism along with the support blocks and barrier arms. Place these on a paper towel off to the side.

3.  Vacuum the trough water off, and wipe the trough surface with a non-lint cloth using 70% ethanol.

4.  Wipe the arms and support blocks with the non-lint cloth using 70% ethanol.

5.  Refill the trough with distilled H20 and again vacuum it off.

6.  While wearing poly gloves, reassemble the trough.

7.  When putting the barrier arms back on trough, hold on end against surface and snap the other end in place.

8.  Make a NaCl solution with a total volume of 2000 mL.

9.  Pour the NaCl solution slowly into the trough until an edge of water forms against the barrier arms.

10.  Replace the plastic covers over the water and trough mechanism.

11.  Close the barriers to see if the water level is too high and overflows.

Calibrating the Pressure Sensor

1.  Remove the plastic cover trough while leaving the cover over the water surface.

2.  Hang the metal hanger with metal dish from the pressure sensor. Make sure the metal dish does not touch the water surface.

3.  Under the Calibrations menu, choose Calibrate Pressure Sensor.

4.  Steady the hanger by holding tweezers against it and then replace the trough cover. When the pressure value no longer fluctuates, click the Take Pressure button.

5.  Remove the trough cover and add the triangular weight to the metal dish. Again steady the hanger’s swinging and replace the trough cover. When the fluctuations of pressure are minimal, click Take Pressure.

6.  Remove the hanger including the metal dish from the pressure sensor and replace them with two S hangers with a piece of filter paper attached at the bottom. It is expected that the filter paper will be immersed slightly.

Setup and Running the Experiment

1.  Cut a piece of mica large enough to cover the slide holder in order to create a well for the mica later on. Label the clean side with an initial.

2.  Clip this mica to the trough dipper and lower it into the water until the clip is just above the water surface.

3.  Zero the pressure by clicking on the Z button. Set the dipper speed to 0.5 and the target pressure to 35.

4.  Under Dipper menu, click Fast Runup. This is a way to make sure the mica will clear the water when coming out of the trough. (for inner monolayer only)

5.  Add lipid to the surface of the trough area (~15 mL) using a 25 mL syringe. Wait 15 minutes allowing the solvent to evaporate. (Barrier arms should be open).

6.  Close the barrier arms by clicking on the C button. Observe the pressure. If the pressure does not increase, it means there is a leak somewhere.

7.  Under the Barrier menu, click Isotherm. After this is completed, save the display as Isotherm under a folder named as the date for that day.

8.  Clear the screen and under the Barrier menu, click Pressure Control.

9.  When the pressure reaches the value of the target pressure, under the Barrier menu, click Creep Up.

10.  Wait for the mica to be completely out of the water and then save the display as DPPE Deposition in the same folder for that day.