Thermodynamics in a millionth of a millionth of a second

Fundamental biological processes, like the formation of fibrils – fine, thread-like structures made from bundles of protein filaments that serve as a major component of various tissues and cells – as well as the folding of proteins or protein aggregation as a sign of neurological diseases – are non-equilibrium processes. “This means that they can be initiated by minor changes in external conditions, such as temperature,” explains Martina Havenith. Although all these processes occur in a solvent – in this case, water – the interaction with the water molecules was previously neglected.

With terahertz calorimetry, Havenith and her team have used the Advanced Grant from the European Research Council to develop a method that makes it possible to quantitatively deduce thermodynamic magnitudes that determine the course of biological functions from spectroscopic measurements.

New frequency range utilized

“This allows us, for the first time, to measure spectroscopically the thermodynamics of the interaction between proteins and water,” says the researcher. The team is conducting measurements in the Terahertz range of the electromagnetic spectrum, which was previously not accessible experimentally.  With precise spectroscopic measurements and a new theoretical concept, the researchers were able to discover a 1:1 correlation between the spectroscopic measurement data and thermodynamic quantities, such as heat capacity or free energy.

This makes it possible to utilize all the benefits of laser-spectroscopic methods in the future. “We can now use extreme temporal resolution of a millionth of a millionth of a second to examine thermodynamic equilibration in chemical reactions in real time for the first time,” says Havenith. Measurement in the smallest nanocontainers and local hot spots during the formation of neurotoxic aggregates is now within reach.