Combined Super-Resolution Fluorescence and Coaxial 3-D Scanning Microwave Microscopy: Proof-of-Concept In-Liquid Live-Cell Imaging: Toward a Biological Nano-Radar
Résumé
We present a proof-of-concept 3-D scanning
microwave microscope based on a miniaturized coaxial probe
combined with high-resolution fluorescence microscopy for
in-liquid operation and live-cell imaging. The system simulta-
neously provides electric (GHz) and optical (super-resolution)
imaging of live cells for broad applications in life sciences. It com-
bines advantages offered by both open-ended coaxial probing and
near-field scanning microwave microscopy (SMM) for accurate
and quantitative local microwave measurements. The shielded tip
minimizes unwanted absorption of microwaves by the biological
media as compared to fringe fields of unshielded tips which we
previously showed absorb over 90% of the signal and mask the
true imaging signal. A proof-of-concept system built up with
commercial off-the-shelf (COTS) components is demonstrated
in the frequency range 0.01–6 GHz with micrometric spatial
resolution, only limited by the coaxial probe geometry. Our
work at the microscale lays the technological foundation for a
true nano-radar in liquid cell imaging system that will come
with further advances in nanofabrication technologies applied to
coaxial probes and can be integrated with super-resolution optical
microscopy, for an integrated full electromagnetic spectrum to
probe biology at the nanoscale, from dc to lightwave.