posted on 2018-06-18, 00:00authored bySebastian A. Thompson, Ignacio A. Martínez, Patricia Haro-González, Alejandro P. Adam, Daniel Jaque, Jana B. Nieder, Roberto de la Rica
Temperature
is a crucial parameter in biology, nanoelectronics,
nanophotonics, and microfluidics. Optical methods excel for measuring
temperature because they are noninvasive, spatially accurate, and
can measure real time local changes in temperature. Among these, fluorescence
anisotropy-based methods are particularly advantageous because they
are less affected by changes in the probe concentration and irradiation
conditions. However, at physiologically relevant temperature ranges
in aqueous solution, fluorescence anisotropy contrast can only be
achieved with rather large fluorescent proteins such as the green
fluorescent protein (GFP), which can limit the range of applications
through this method. Here, we propose a method to add thermosensitivity
to any protein thereby transforming them into fluorescence anisotropy-based
thermoprobes. It consists of covalently attaching a dye to the protein,
which increases the rotational time of the dye-protein system compared
to the free dye and confers thermosensitivity to the resulting bioconjugates.
With this method we transformed bovine serum albumin, glucose oxidase
and catalase into nanothermothers. This also allowed us to analyze
the anisotropy signal changes occurring during the catalytic cycle
of catalase, as well as their correlation with the reaction exothermicity.
The potential of this method ensures applicability in extending temperature
measurements to any protein-based experiments.