Novel gene assay by probe-regulated simultaneous separation using capillary electrophoresis (CE-PRESS)

A novel methodology, a probe-regulated simultaneous separation using capillary electrophoresis (CE-PRESS), was developed for simultaneous assay of multiple genes. The single-stranded (ss) DNA-polymer conjugate-probes were placed in a capillary, and then a mixture of target ssDNAs was injected. These ssDNAs were hybridized with corresponding complementary ssDNA-polymer conjugate-probes after charging the capillary. Two resulting double-stranded (ds) complexes of ssDNAs and ssDNA-polymer conjugate-probes were detected at different migration times. We found that the electrophoretic mobilities of two ssDNA-poly(acrylamide) conjugate-probes [-(5'-GCCACCAGC-3')m-AAm(n)- and -(5'-ACCTTCACT-3')p-AAm(q)-; AAm, acrylamide] obtained by copolymerizing 5'-methacryloyl-modified ssDNA and AAm were different, depending on their molar fraction of ssDNA, although the ssDNAs chain lengths were the same. Two ssDNAs (5'-GCTGGTGGC-3' and 5'-AGTGAAGGT-3') having the same chain length were successfully separated with our novel system, although the separation of these ssDNAs is impossible in conventional capillary electrophoresis systems.