Synchrotron Radiation for On-chip Mid-ir Detection at the Diffraction Limit

Microchips for rapid mixing of two aqueous streams have been produced using CaF2 wafers and SU-8 microstructuring technology and tested at the IR beamline of Bessy II in Berlin, Germany. Advantage of the synchrotron radiation over thermal globar sources for measuring at sample spots close to the diffraction limit of the employed mid-IR radiation have been documented. The capability of the experimental set-up to initiate and monitor chemical reactions label-free in pL volumina was verified. Simple chemical reactions such as titration of acetic acid and conformational change of the protein β2-microglobulin have been recorded.