Rapid serial analysis of multiple oligonucleotide samples on a microchip using optically-gated injection

Optically-gated injection of fluorescently-labeled DNA has been accomplished for the first time. Rapid, serial analysis of oligonucleotide ladders has been shown on a microchip using this injection technique. Separations of five- and six-component samples have been completed in 60 s or less with a capability to carry out serial injections of these samples every 15 s. The technique has been shown to have better than five base resolution for small oligonucleotides and excellent reproducibility in migration times (≤0.75% RSD). Currently, the limit of detection for the system is 0.23 μM. Additionally, multiple unique samples of DNA have been consecutively analyzed in a single separation lane using optical gating. Six consecutive injections of three different samples have been achieved with no sample carryover and a total analysis time of ∼10 min. These results show the potential of optical gating as an alternative injection technique for high-throughput DNA applications, such as genotyping and monitoring dynamic processes.