Preserving biological materials is becoming more and more important for a broad range of different fields. Pharmaceutics are becoming increasingly structurally complex and are therefore inherently less stable which increases the need for these to be stabilized by different methods for long-term storage. Furthermore, advances in biotechnology related to, for example, tissue engineering and blood transfusion increases the demand for techniques of storing large complex biological materials. In order to develop such techniques, researchers have taken inspiration from different organisms, such as the tardigrade, which are capable of surviving extreme environments for extended periods of time. It has been found that many of these so-called extremophiles use different types of sugar molecules to survive harsh conditions. Among these sugar molecules, the disaccharide trehalose has been found to have extraordinary protective properties. Therefore, by studying the interaction of trehalose with different biological materials it is possible to learn more about how to improve different preservation techniques, such as cryopreservation or freeze-drying.
In this thesis, I investigate how proteins and their environments are affected by the presence of trehalose. In order to investigate this, I have mainly used different types of neutron scattering techniques in combination with molecular simulations, thermodynamic measurements, and dielectric spectroscopy methods.
First, the molecular structure of a mixture of trehalose and water is investigated and compared to a similar system containing another common protective sugar molecule, namely sucrose. The results from these studies indicate that both these sugars exhibit a surprisingly similar structure. Secondly, the molecular structure and dynamics of protein, trehalose, and water-mixtures at different compositions are investigated. From those studies it is shown that the protein molecules prefer to interact with water, thus partially excluding the trehalose molecules from interacting directly with the protein surfaces. It is also shown that the trehalose molecules help to prevent different protein molecules from coming into contact with each other, and that the motions of the protein are slowed down due to a coupling to the trehalose molecules via the water layer at the protein surface.
It is my hope that the presented results will benefit in the pursuit of understanding how trehalose function as a biological stabilizer and may thus help guide future development of improved biomolecular perseveration techniques.