Label-Free
High-Resolution Photothermal Optical Infrared
Spectroscopy for Spatiotemporal Chemical Analysis in Fresh, Hydrated
Living Tissues and Embryos
posted on 2023-11-02, 20:07authored byNika Gvazava, Sabine C. Konings, Efrain Cepeda-Prado, Valeriia Skoryk, Chimezie H. Umeano, Jiao Dong, Iran A. N. Silva, Daniella Rylander Ottosson, Nicholas D. Leigh, Darcy Elizabeth Wagner, Oxana Klementieva
Label-free chemical
imaging of living and functioning systems is
the holy grail of biochemical research. However, existing techniques
often require extensive sample preparation to remove interfering molecules
such as water, rendering many molecular imaging techniques unsuitable
for in situ structural studies. Here, we examined freshly extracted
tissue biopsies and living small vertebrates at submicrometer resolution
using optical photothermal infrared (O-PTIR) microspectroscopy and
demonstrated the following major advances: (1) O-PTIR can be used
for submicrometer structural analysis of unprocessed, fully hydrated
tissue biopsies extracted from diverse organs, including living brain
and lung tissues. (2) O-PTIR imaging can be performed on living organisms,
such as salamander embryos, without compromising their further development.
(3) Using O-PTIR, we tracked the structural changes of amyloids in
functioning brain tissues over time, observing the appearance of newly
formed amyloids for the first time. (4) Amyloid structures appeared
altered following standard fixation and dehydration procedures. Thus,
we demonstrate that O-PTIR enables time-resolved submicrometer in
situ investigation of chemical and structural changes in diverse biomolecules
in their native conditions, representing a technological breakthrough
for in situ molecular imaging of biological samples.