Biomod/2012/Titech/Nano-Jugglers/Results/Azobenzene Tweezer

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No. Solusion(time irradiating UV-light(minute)) light wavelength(nm) absorbance
1 A(0) 265 0.224
2 B(0) 261 0.153
3 A+B(0) 263 0.138
an average absorbance of number 1 and 2
4 A+B(1) 262 0.179
5 A+B(5) 262 0.179
6 A+B(30) 262 0.178
:A: Azobanzen including ssDNA
:B: Normal ssDNA which is complimentary DNA with A
:A+B: this solution include A and B
The above table shows the relationship between the time of irradiating UV-light and the absorbance of photoresponsive DNA. The detail is on the page 'Azobenzen Protocol'.


A relational expression about absorbance can be expressed as follows.
(Abs: absorbance, ε: the absorption coefficient, c: strength, d: length of a visual leg )
Solution A+B include 5µM strength of DNA i and DNA ii, so when no DNA formed duplex in the solution A+B, we can simply calculate its absorbance. The value is 188.5(calculated an average absorbance of No.1 and 2). Compared with this value and the absorbance of No.3, the former is 37% larger than the latter. In brief, We thought this difference comes from that DNA formed duplex in the solution of No.3 and interactions between base pairs decrease the UV absorbance relative to single strands.
In this point, we believed that the complementary photo-responsive DNAs can form duplex.
Look at the absorbance of No.3 and No.4~6, as the solution A+B was irradiated longer time, its absorbance suddenly move upwards from a border between No.3 and No.4. We thought this difference comes from that DNA duplex completely dissociated in the solution of No.4~6 due to more than 1 minute irradiation of the UV-light.
In this point, we believed that the photo-responsive DNA duplex which we designed can be dissociated with irradiation of the UV-light.
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