Hi all,
Am working on a DNA based biosensor, DNA are thiolated. i reduce thiolated ssDNA by TCEP and dip cast it on a gold nanoparticle coated electrode.
I have tried with 500nM , 1uM, 2uM, 3uM, 4uM and 5uM concentrations, but am not getting a constant value by DPV.
i use methylene blue as indicator, should i have to refrigerate the methylene blue after use.
i need to fix the probe concentration.
Can some one share their insights on this, that would be great help.
Hello Manohar Raju
Are you adjusting the probe density on the gold surface using a "spacer" molecule (e.g., 6-Mercapto-1-hexanol)?
You say "dip cast"... Do you mean "drop cast"? I would imagine the latter will provide a more reproducible coverage as you can better control the volume of solution and therefore mass of probe that comes into contact with the surface.
What is the rest of your protocol? Do you perform "backfilling" of the gold surface to ensure complete surface coverage with thiols? Do you then allow the electrode to dry? Do you rinse, if so with DI H2O or a buffer?
You may find the experimental information in the following article helpful:
Article Self-assembled gold nanoparticles for impedimetric and amper...
Jules
Dear Hammond,
The oligo am using is Thiol C6-Modified, The electrodes are so small that, it can be dipped in 96 Well plates. Am adding 150ul of Oligo's of different concentrations to the well (the volume is made such that the working electrode has to be completely submerged) and dipped the electrode for 180 mins at 30o C. Washed with buffer to remove any unbound oligo's and treated with 6-Mercapto-1-hexanol (MCH) for an hour at 30o C, further washed with buffer to remove any unbound MCH and electrochemical studies are carried out.
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