Sahin Solmaz, Nergiz, Marco Grisi, Alessandro V. Matheoud, Gabriele Gualco, and Giovanni Boero. “Single-Chip Dynamic Nuclear Polarization Microsystem.” Analytical Chemistry 92, no. 14 (July 21, 2020): 9782–89.
https://doi.org/10.1021/acs.analchem.0c01221
The integration on a single chip of the sensitivity-relevant electronics of nuclear magnetic resonance (NMR) and electron spin resonance (ESR) spectrometers is a promising approach to improve the limit of detection, especially for samples in the nanoliter and subnanoliter range. Here we demonstrate the co-integration on a single silicon chip of the front-end electronics of an NMR and an ESR detector. The excitation/detection planar spiral microcoils of the NMR and ESR detectors are concentric and interrogate the same sample volume. This combination of sensors allows to perform dynamic nuclear polarization (DNP) experiments using a single-chip integrated microsystem having an area of about 2 mm2. In particular, we report 1H DNP-enhanced NMR experiments on liquid samples having a volume of about 1 nL performed at 10.7 GHz(ESR)/16 MHz(NMR). NMR enhancements as large as 50 are achieved on TEMPOL/H2O solutions at room temperature. The use of state-of-the-art submicrometer integrated circuit technologies should allow the future extension of the single-chip DNP microsystem approach proposed here up the THz(ESR)/GHz(NMR) region, corresponding the strongest static magnetic elds currently available. Particularly interesting is the possibility to create arrays of such sensors for parallel DNP-enhanced NMR spectroscopy of nanoliter and subnanoliter samples.