Protocol for washing and modifying QCM-D sensors
Prepare solutions of 2% SDS, 0.1% SDS and 0.1 M HCl.
Clean the gold-coated QCM-D sensors by hand with 2% SDS to mechanically remove contaminants.
Be sure that the glove is wet all the time so it doesn't scratch the sensor!
Place the sensors in a stand and put them in a 0.1% SDS solution.
Heat for 10 min at 80°C, then rinse the sensors with water.
Place the sensors in a 0.1 M HCl solution.
Heat for 10 min at 80°C, then rinse the sensors with water several times to remove all HCl solution.
Then blow the sensors dry under a flow of nitrogen.
Make an ethanolic solution with total concentration 10 mM of mixed PEG thiols (PEG and biotin-PEG thiols in a molar ratio of 99:1).
(MW, dS-PEG = 386.5 Da and MW, dS-PEG-biotin = 788.0 Da) Incubate the QCM-D sensors in the ethanolic PEG thiol solution for at least 16 hours at 4°C in darkness.
Rinse the sensors a couple of times with ethanol, then a couple of times with milli-Q water and lastly blow them dry with nitrogen.
They may now be used or stored.
