| Abstract
| - We demonstrate electrophoresis in I-shaped microchannels with a new design and operation principle. Unlikethe conventional T- or cross-shaped microchannels, thesimple I-shaped design makes it straightforward to integrate parallel microchannels with electrodes onto a microchip. The operation of the I-shaped microchannels hasbeen enabled by the autonomous solution filling technique, which exploits the high gas solubility in poly(dimethylsiloxane) (PDMS). We fabricated an I-shapedmicrochannel array (IMA) chip by integrating 12 independent microchannels and 2 electrodes onto a 3 cm ×2 cm area in a PDMS−glass hybrid microchip. Forautonomous regulation of stable sample plugs in all themicrochannels, we discovered that O2 plasma treatmentof the PDMS-made reservoirs is effective. On the IMAchip, size-dependent separation of double-stranded (ds)DNA and sequence-specific separation of single-strandedDNA were achieved. Specifically, 10 fragments in a 100−1000-bp dsDNA ladder were separated using hydroxyethylcellulose as a sieving matrix within a separationlength of 2 mm, and polymerase chain reaction productsof the wild-type K-ras gene and its point mutant wereseparated using a probe DNA−poly(dimethylacrylamide)conjugate on the basis of affinity capillary electrophoresis.The IMA chip presented here opens up a new possibilityof large-scale integration of microchannels for high-throughput electrophoretic analyses.
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