Easy SNPs typing on an autonomous microchip

 

Human genomic variation is now becoming important information for prevention and treatment of diseases. The most common form of the variation is single-nucleotide polymorphism (SNP) which means substitution of a single base. We are now developing rapid and reliable methods for typing of SNPs. Here we introduce such a method including two original technologies: "autonomous microchip" and "affinity electrophoresis."

 

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Fig 1. Electrophoresis on an autonomous microchip.

 

The autonomous microchip is made of silicone elastomer: poly(dimethylsiloxane) (PDMS). PDMS has a high gas solubility that we exploited for autonomous formation of a liquid-liquid interface between sieving polymer matrix and sample solution in a microchannel. For affinity electrophoresis, a probe DNA is immobilized to the sieving polymer matrix. Migrating through the matrix, sample DNA is concentrated and separated by interaction with the probe DNA. With this method, we can concentrate two 60-base DNAs by a factor of 100, and can separate them by a single-base substitution.

 

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Fig 2. (a) Schematics of affinity electrophoresis.

(b) Concentration and sequence-specific separation of 60-base DNAs.

 

Reference

(1)

Ito, T., Inoue, A., Sato, K., Hosokawa, K., and Maeda, M.: “Autonomous polymer loading and sample injection for microchip electrophoresis” Analytical Chemistry, 77, 4759-4764 (2005).

(2)

Ito, T., Inoue, A., Sato, K., Hosokawa, K., and Maeda, M.: "Affinity capillary electrophoresis in a poly(dimethylsiloxane)-glass hybrid microchip" Chem. Lett. 32, 688-689 (2003).

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