Posted by chen1431 on May 6, 2008 04:54 AM|Permalink
Comments
1. In these experiments, it appears that K+ is used to depolarize the cells that induces neurotransmitter release. However, K+ would change the impedance causing a drastic movement in the electrode. What do they do to solve this issue?
2. What would be the smallest electrode that one could use? Would there be an improvement in resolution? Would there be an improvement in S/N?
I believe the smallest electrode that can be used in this case is on a nm scale. I'm not sure exactly what size, but somewhere between 50-100 nm. I believe the electrode is more sensitive so the signal to noise ratio increases.
1 The application of K+ solution will cause a large decrease of the impedance but the impedance recovers to baseline levels within seconds. That is to say, it is possible to investigate more isolated release events taking place after the impedance returns to the baseline. In order to solve this issue, the authors operating SECM in the constant-height mode rather than in constant-distance mode. In this case, the change in background impedance due to K+ will not obscure the variations in impedance arising from the cell topography.
2 In Phil's class, he said that the smallest electrode that one can use is in micrometer scale and that is the limitation of the SECM resolution. The smaller electrode we use, the better resolution and larger S/N.
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Comments
1. In these experiments, it appears that K+ is used to depolarize the cells that induces neurotransmitter release. However, K+ would change the impedance causing a drastic movement in the electrode. What do they do to solve this issue?
2. What would be the smallest electrode that one could use? Would there be an improvement in resolution? Would there be an improvement in S/N?
Posted by: Edgar Arriaga | May 6, 2008 11:29 PM
Answer to Question 2
I believe the smallest electrode that can be used in this case is on a nm scale. I'm not sure exactly what size, but somewhere between 50-100 nm. I believe the electrode is more sensitive so the signal to noise ratio increases.
Posted by: Anja Lesaja | May 7, 2008 07:28 PM
1 The application of K+ solution will cause a large decrease of the impedance but the impedance recovers to baseline levels within seconds. That is to say, it is possible to investigate more isolated release events taking place after the impedance returns to the baseline. In order to solve this issue, the authors operating SECM in the constant-height mode rather than in constant-distance mode. In this case, the change in background impedance due to K+ will not obscure the variations in impedance arising from the cell topography.
2 In Phil's class, he said that the smallest electrode that one can use is in micrometer scale and that is the limitation of the SECM resolution. The smaller electrode we use, the better resolution and larger S/N.
Posted by: Li Chen | May 8, 2008 12:35 AM