Abstract

The aim of this thesis is to investigate biomaterials using one and two-dimension Laplace Nuclear Magnetic Resonance (LNMR). LNMR is a class of NMR experiments that cover relaxation and self-diffusion measurements. Multidimensional LNMR experiments improve resolution and enable correlating relaxation and diffusion parameters. However, multidimensional experiments are limited by their long experiment times. To overcome this issue, acceleration methods can be used, such as ultrafast Laplace NMR (UF LNMR), which allows for measuring two-dimension data in a single scan.

The first part of the thesis focuses on investigating the pore structures of cellulose nanofibril (CNF) aerogels using NMR cryoporometry, diffusometry, and magnetic resonance imaging (MRI). Aerogels are a special kind of material which have low density and high surface area. CNF aerogels are environmentally friendly and utilized as oil and chemical spill sorbents. The NMR methods allowed us to determine the nano-, micro- and submillimeter scale pore size distributions of CNF aerogels.

The second part of the thesis concentrates on accelerating restricted diffusion measurements. Two different accelerating strategies were used. In the ultrafast approach, various effective gradient pulse lengths are encoded into a layer of the sample in a single scan. In the time-resolved approach, random increments of gradient strengths are associated with a constant increase in diffusion delay. Both methods were shown to be able to measure the restricted diffusion of water molecules inside a thermally modified wood sample with a ten-fold decreased experiment time.

The third part of the thesis focuses on evaluating the changes in cheese structure during ripening using a single-sided NMR magnet. The cheese structure was monitored using one- and two-dimensional T₂, T₁-T₂, and D-T₂ NMR experiments. The experiments enabled observation of the three main components of cheese, namely water, fat, and water associated with casein protein as well as monitoring their evolution as a function of ripening time.

In the last part of the thesis, we demonstrate that ultrafast diffusion exchange spectroscopy (UF DEXSY) experiments are feasible by a single-sided NMR magnet. Significant sensitivity boost provided by dissolution dynamic nuclear polarization (dDNP) method enabled single-scan UF DEXSY measurements in a fraction of a second. We exploited the method in the investigation of water exchange between intra- and extracellular pools in fresh yeast cells.

Osajulkaisut / Original papers

Osajulkaisut eivät sisälly väitöskirjan elektroniseen versioon. / Original papers are not included in the electronic version of the dissertation.

1. Kharbanda, Y., Urbańczyk, M., Laitinen, O., Kling, K., Pallaspuro, S., Komulainen, S., Liimatainen, H., & Telkki, V.-V. (2019). Comprehensive NMR analysis of pore structures in superabsorbing cellulose nanofiber aerogels. The Journal of Physical Chemistry C, 123(51), 30986–30995. https://doi.org/10.1021/acs.jpcc.9b08339

   Rinnakkaistallennettu versio / Self-archived version

2. Urbańczyk, M., Kharbanda, Y., Mankinen, O., & Telkki, V.-V. (2020). Accelerating restricted diffusion NMR studies with time-resolved and ultrafast methods. Analytical Chemistry, 92(14), 9948–9955. https://doi.org/10.1021/acs.analchem.0c01523

   Rinnakkaistallennettu versio / Self-archived version

3. Kharbanda, Y., Mailhiot, S., Mankinen, O., Urbańczyk, M., & Telkki, V.-V. (2022). Monitoring cheese ripening by single-sided nuclear magnetic resonance. Manuscript submitted for publication. https://doi.org/10.3168/jds.2022-22458

   Rinnakkaistallennettu versio / Self-archived version

4. Kharbanda, Y., Urbańczyk, M., Zhivonitko, V. V., Mailhiot, S., Kettunen, M. I., & Telkki, V-V. (2022). Sensitive, efficient and portable analysis of molecular exchange processes by hyperpolarized ultrafast NMR. Angewandte Chemie International Edition, 61(28). https://doi.org/10.1002/anie.202203957

   Rinnakkaistallennettu versio / Self-archived version