3.3 Cleaning
and Preparation
of Qsense SiO 2
Sensors (See Note 11)
1. Clean and prepare sensors immediately prior to use.
2. Sonicate sensors in 2% SDS (w/v) for approximately 15 min to
remove bound particles. Rinse both sides of sensors with copious amounts of ultrapure water. Hold the sensor by the outer
edge O-ring using tweezers and ensure that none of the surface
or electrodes are touched (see Note 12).
3. Rinse surfaces with ethanol and dry under nitrogen stream to
ensure that no streaks are present. Liquid should be chased off
the crystal rather than being evaporated on it (see Note 13).
4. Place sensor in UV Ozone cleaner with SiO 2 surface facing
upward. Clean for 30 min and use immediately (see Note 14).
3.4 Lipid Bilayer
Formation
Using QCM-D
For this method, measurements were taken using the Q-sense E1
system with external peristaltic pump as sample feeder. Adaptations
to the following method can be made for use with alternative
QCM-D systems.
3.4.1 Mounting Sensor
in the E1 System
1. Remove flow module from chamber platform. Unscrew the
flow module and remove the contact block (upper casing).
Ensure that the chamber void is dry and O-ring is lying flat in
its bed (see Note 15).
2. While holding the sensor by its outer edge and using tweezers,
place the sensor on the chamber O-ring with the SiO 2 surface
facing downward toward the chamber wall. The electrode
should be facing to the left and match up with the electrode
shape on the module.
3. Screw the contact block back onto the flow module ensuring
not to disturb the sensor. Place in the chamber platform with
the electrode pins facing downward. Replace the lid of chamber
platform.
4. Connect pump and tubing to the flow module.
3.4.2 Lipid Bilayer
Deposition
and Measurement
Procedure
1. Open the Qsoft software. Activate temperature control and set
desired temperature to 20
C. Wait for temperature equilibration (approximately 5–10 min) (see Note 16).
2. Place inlet tubing into running buffer (filtered and degassed
10 mM HEPES, 150 mM NaCl, and 2 mM CaCl 2 (pH 7.4)
aliquoted into appropriate vessel). Run the pump at 100 μL/
min and fill flow module with running buffer (see Note 17).
3. Start data acquisition and find the specific resonances 3, 5,
7, 11, and 13. Ideally wait for all resonances to be found.
Viscoelastic modeling requires only three resonances, which
do not need to be in order. Wait for reading to equilibrate ( f
and D signal is a stable plateau) which will take approximately
10–15 min (see Note 18).
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Holly L. Birchenough and Thomas A. Jowitt
and Preparation
of Qsense SiO 2
Sensors (See Note 11)
1. Clean and prepare sensors immediately prior to use.
2. Sonicate sensors in 2% SDS (w/v) for approximately 15 min to
remove bound particles. Rinse both sides of sensors with copious amounts of ultrapure water. Hold the sensor by the outer
edge O-ring using tweezers and ensure that none of the surface
or electrodes are touched (see Note 12).
3. Rinse surfaces with ethanol and dry under nitrogen stream to
ensure that no streaks are present. Liquid should be chased off
the crystal rather than being evaporated on it (see Note 13).
4. Place sensor in UV Ozone cleaner with SiO 2 surface facing
upward. Clean for 30 min and use immediately (see Note 14).
3.4 Lipid Bilayer
Formation
Using QCM-D
For this method, measurements were taken using the Q-sense E1
system with external peristaltic pump as sample feeder. Adaptations
to the following method can be made for use with alternative
QCM-D systems.
3.4.1 Mounting Sensor
in the E1 System
1. Remove flow module from chamber platform. Unscrew the
flow module and remove the contact block (upper casing).
Ensure that the chamber void is dry and O-ring is lying flat in
its bed (see Note 15).
2. While holding the sensor by its outer edge and using tweezers,
place the sensor on the chamber O-ring with the SiO 2 surface
facing downward toward the chamber wall. The electrode
should be facing to the left and match up with the electrode
shape on the module.
3. Screw the contact block back onto the flow module ensuring
not to disturb the sensor. Place in the chamber platform with
the electrode pins facing downward. Replace the lid of chamber
platform.
4. Connect pump and tubing to the flow module.
3.4.2 Lipid Bilayer
Deposition
and Measurement
Procedure
1. Open the Qsoft software. Activate temperature control and set
desired temperature to 20
C. Wait for temperature equilibration (approximately 5–10 min) (see Note 16).
2. Place inlet tubing into running buffer (filtered and degassed
10 mM HEPES, 150 mM NaCl, and 2 mM CaCl 2 (pH 7.4)
aliquoted into appropriate vessel). Run the pump at 100 μL/
min and fill flow module with running buffer (see Note 17).
3. Start data acquisition and find the specific resonances 3, 5,
7, 11, and 13. Ideally wait for all resonances to be found.
Viscoelastic modeling requires only three resonances, which
do not need to be in order. Wait for reading to equilibrate ( f
and D signal is a stable plateau) which will take approximately
10–15 min (see Note 18).
190
Holly L. Birchenough and Thomas A. Jowitt