Добавил:
masterdos
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Мікро- та наносенсори / L2.9.pdf
Broad range of nanobiosensors
Nano Cantilever (~pM)
Si-NW/CNT (nM-aM)
Nano-Net (nM-pM)
Nanodots
Array sensors (~pM)
ChemFET/IsFET (~mM)
Biobarcode (~aM)
9
Settling time: Problem definition
|
|
|
|
|
W |
d ρ |
2 |
|
|
|
|
|
|
|
|||
|
|
|
|
|
|
|||
|
|
|
|
|
|
|||
|
|
|
|
|
|
|
= D |
ρ |
|
|
|
|
|
|
dt |
||
|
|
|
|
|
|
|||
|
|
|
|
|
|
ddNt = kF (N0 − N)ρs
The diffusion-capture problem is very challenging, especially for complex capture surfaces
10
Strategy: Solution of the Diffusion-capture problem by Transient diffusion capacitance
1 |
N (t)=C0 ρ0t A |
||
2 |
Look up electrostatic C0 |
||
|
|
|
|
|
ε → D W → 2nDt |
||
3 |
Calculate time to reach |
||
|
N (ts )= Ns |
||
4 |
Plot log ts vs. log ρ0 |
||
|
|
|
|
ρs 
ρ0 |
W (t) = |
2nDt |
|
|
|
|
|
|
C0,0 |
= |
4πD |
|
|
a0−1 −(W +a0 )−1 |
||||
|
|
|||
CD(t) = 4πD −1 a0−1 −(
6Dt +a0 )
11
A fundamental relationship of biosensor
D=1 |
|
|
1<D<2 |
|
|
|
D=2 |
|
|
|
|
3−D |
|
Fractal dimension |
|
|
|
|
|
||||
|
|
|
− |
2 |
F |
|
|
Limits of |
|
|
|
|
|
|
|
|
ρ0 |
~ Ns ×ts |
|
|
|
Settling (response) time |
|
detection |
|
|
|
|
|||
|
|
|
|
|
|
|
|
Minimum number of analyte (depends on transduction) … and the relationship applies even for complex sensors
12