Assessment of activity of antigens (allergens) immobilised on sensor chips by Dual polarization interferometry (DPI) (CAT#: STEM-MB-0408-WXH)

Name: Assessment of activity of antigens (allergens) immobilised on sensor chips by Dual polarization interferometry (DPI)
SKU: STEM-MB-0408-WXH
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Introduction

In many applications, such as point-of-care allergy tests, it is necessary to immobilise proteins onto a sensor surface and to store them for an extended period of time. However, the direct attachment of a protein to a surface without a spacer can cause steric constraint of the protein's reactivity or interaction capability compared to the protein in solution. Moreover, multiple direct contacts with the surface can induce denaturation. By introducing a spacer between the protein and the reactive group on the surface, these effects can be minimised.

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Principle Applications Procedure Materials

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

Assessment of activity of antigens (allergens) immobilised on sensor chips.
Study of point-of-care allergy tests

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