We demonstrate microfluidic devices for terahertz spectroscopy of biomolecules in aqueous solutions. The devices are fabricated out of a plastic material that is both mechanically rigid and optically transparent with near-zero dispersion in the terahertz frequency range. Using a low-power terahertz time-domain spectrometer, we experimentally measure the absorption spectra of the vibrational modes of bovine serum albumin from 0.5–2.5 THz and find good agreement with previously reported data obtained using large-volume solutions and a high-power free-electron laser. Our results demonstrate the feasibility of performing high sensitivity terahertz spectroscopy of biomolecules in aqueous solutions with detectable molecular quantities as small as 10 picomoles using microfluidic devices.
P. A. George, W. Hui, F. Rana, Benjamin G. Hawkins, A. E. Smith, and B. J. Kirby. "Microfluidic devices for terahertz spectroscopy of biomolecules" Optic Express (2008): 1577-1582. https://doi.org/10.1364/OE.16.001577