posted on 2021-02-17, 16:08authored byAlice Spadea, Joanna Denbigh, M. Jayne Lawrence, Mustafa Kansiz, Peter Gardner
This paper reports the first use of a novel completely optically
based photothermal method (O-PTIR) for obtaining infrared spectra
of both fixed and living cells using a quantum cascade laser (QCL)
and optical parametric oscillator (OPO) laser as excitation sources,
thus enabling all biologically relevant vibrations to be analyzed
at submicron spatial resolution. In addition, infrared data acquisition
is combined with concomitant Raman spectra from exactly the same excitation
location, meaning the full vibrational profile of the cell can be
obtained. The pancreatic cancer cell line MIA PaCa-2 and the breast
cancer cell line MDA-MB-231 are used as model cells to demonstrate
the capabilities of the new instrumentation. These combined modalities
can be used to analyze subcellular structures in both fixed and, more
importantly, live cells under aqueous conditions. We show that the
protein secondary structure and lipid-rich bodies can be identified
on the submicron scale.