I am trying to cast Glucose Oxidase using Nafion (10% w/v) and its 3.5 % solution in water to produce membrane to hold the enzyme on stainless steel electrode. But when I run CV in glucose solution the the electrode washed away. Any solution???
Hi Nadeem,
I would check in the literature first what is the charge of your electrode, which it is most probably negative charged at most pHs. Nafion is also negative charged at most pHs and GOx (pI approximately 4.2) is (making a simplification) positive charged bellow pH 4.2 and negative charged above pH 4.2.
So you are trying to bind three materials that are most probably negative charged at the conditions you are using, which means that a repulsions will occur during immobilization. I will maybe first add a positive charged polymer over the stainless steel (PEI for example), then the enzyme and finally the Nafion over the PEI-enzyme conjugate. This means a LbL modification in three steps.
On another approach I would modify stainless steel to change the charge with some chemical method, for example using electrochemical grafting of diazonium salt, which are cheap and easy to immobilize (but quite toxic).
Hope this helps but just drop me an email if you need more help.
Cheers,
Roberto
Detachment of sensing layers from any electrodes is a common problem. One of the simple solutions is pretreat the surface with polyethyleneimine (PEI) as suggested by Roberto. Immerse the electrode in 1-10 mg/ml PEI solution in water for 5-10 min. After that wash the electrode with water or buffer. After this procedure, approx. a monolayer of PEI will be left on the electrode surface. This procedure usually helped me to get good attachment of sensing layers comprised of nanoparticles, etc.
Dear Ruzgas,
Thanks a lot. I will try with PEI as suggested by Roberto and you.
Regards,
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