Detection of DNA molecules in micro fluidic channels by infrared absorption spectroscopy

Infrared absorption spectroscopy (IRAS) in a multiple internal reflection (MIR) geometry is integrated with silicon-based micro-fluidic channels to allow detection and separation of DNA molecules in the micro-channels. The micro-channels were fabricated on a Si MIR-prism using the conventional silicon lithographic techniques. In the present method we can probe both solution-phase and surface-bound biomolecular species through IR spectral profiles of biomolecules of interest, allowing us to detect biomolecules without fluorescence labeling. The applicability of this approach is demonstrated with a representative test case: transformation of single-stranded DNA molecules (oligonucleotides) in the micro-channels.