Hello all,
We are using screen printed gold electrode(220BT) from Dropsens to build an immunosensor.
To attach the antibody onto the working electrode, we use EDC/NHS with MPA.
From what I understand, we need to restrict the linker and antibody adsorption on working electrode alone. However, many of the paper I read that uses the same electrode only mention they "drop 50 ul of liquid" onto the electrode which got me confused.
From what I can see, any liquid over 10ul will spread from the working electrode and cover the reference and counter electrode but I have not seen much mention of flow chamber or whatever else that can be used to contain the liquid to the working electrode.
Is this something that was just omitted because it is too obvious or is it just common to drop the liquid on to the entire electrode?
If there is an obvious way to isolate the working electrode, could you let me know what it is?
Hello!
What happens is that this type of mofications are carried out when the working electrode is independent of the other two (reference and auxiliary), in addition to using a traditional single compartment cell.
In your case, what you should do is just drop the surface of your working electrode, and then cover all three (WE, AUX and REF) with your work solution, which is where you will carry out your measurements, Remember that what you are looking to evaluate are the redox processes on your electrode and not in the solution. Sometimes, the simplest solutions are the ones that work, you can insulate with parfilm or teflon the surface of the working electrode of the other two electrodes, let the solution with which you modify to dry, remove the parfilm or teflon and cover all the surface of your electrodes with the working solution.
Hello,
I used these sensors functionalizing all three electrodes and it's true, many of the paper I read uses this method. You have to consider though that you will have a modified reference, but it didn't create any big problems for me. I also tried to functionalize by placing 10 uL drop only on the working electrode and placing the devices in a wet room to avoid evaporation. It also works, but you have to be careful to cover the whole area well to have a good reproducibility.
I also used a silicon chamber for an another type of electrodes, to define only the working area, but in this case I used an external reference electrode. I don't think it's possible to use the silicon chamber with DS and then measure normally, at least not using a chamber with an o-ring to the base, so as not to rest on top of the other electrodes, but it is quite difficult.
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