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Detect single-base changes during the toehold-mediated DNA strand-displacement reaction by Dual polarization interferometry (DPI) (CAT#: STEM-MB-0454-WXH)

Introduction

Genetic variations with single-base changes, such as insertions, deletions, and single nucleotide polymorphisms (SNPs), are closely associated with physical and genetic diseases among humans. The genotyping of genetic variations in human DNA is relevant to early diagnosis of diseases, investigation of human response to drugs, and prevention and treatment of specific human diseases. <br />A specific type of DNA hybridization process known as the toehold-mediated DNA strand-displacement reaction can detect SNPs. This reaction can be performed at an ambient temperature without enzyme assistance, and its kinetic rate can be controlled through either adjusting both the length and sequence of the toehold or through UV irradiation.




Principle

Dual polarization interferometry (DPI) is an analytical technique that allows the simultaneous determination of thickness, density, and mass of a biological layer on a sensing waveguide surface in real time. DPI focuses laser light into two waveguides. One of these functions as the "sensing" waveguide having an exposed surface while the second one functions to maintain a reference beam. A two-dimensional interference pattern is formed in the far field by combining the light passing through the two waveguides. The DPI technique rotates the polarization of the laser, to alternately excite two polarization modes of the waveguides. Measurement of the interferogram for both polarizations allows both the refractive index and the thickness of the adsorbed layer to be calculated. These measurements can be used to infer conformational information about the molecular interactions taking place, as the molecule size (from the layer thickness) and the fold density (from the RI) change.

Applications

Detect single-base changes during the toehold-mediated DNA strand-displacement reaction.
Discriminate single-base change (SNPs, insertion or deletion) at an arbitrary position

Procedure

1. Setting of dual polarization interferometry
2. Preparing the DPI sensor chip
3. Immobilization of target on DPI biosensor
4. Reagent was injected to react
5. Quantitative analysis

Materials

• DPI biosensor
• DPI sensor chip