Unveiling the rheology of crosslinked xanthan gum in solution through high-resolution and time domain NMR spectroscopy
Description: Xanthan gum (XG), a polysaccharide produced by Xanthomonas campestris, exhibits remarkable rheological properties and finds diverse applications, ranging from food and oil drilling to medicine. XG's performance is influenced by its conformational changes between helical and random coil states, which are responsive to changes in pH, ionic strength, and temperature. This research proposal aims to elucidate the underlying mechanisms of these supramolecular assemblies through rheological and Nuclear Magnetic Resonance spectroscopic studies. 1H-NMR relaxometry, a powerful technique for studying molecular dynamics, will be employed to investigate the conformational changes of XG. By measuring the longitudinal (T1) and transverse (T2) relaxation times, we can elucidate the structural details of XG in solution. Additionally, diffusion-ordered spectroscopy (DOSY) will provide direct insights into molecular mobility and aggregation processes. To gain a deeper understanding of the cross-linking mechanisms, NOESY experiments will be performed to identify the crucial residues involved in intra- and intermolecular interactions. By combining relaxometric and rheological data, we anticipate developing predictive theoretical models that will significantly advance our understanding of polymer behavior and facilitate the design of novel materials. Therefore, this research will bridge the knowledge gap between supramolecular conformation and cross-linking in macromolecules, paving the way for the design of advanced materials for applications in the health sciences, ultimately leading to breakthroughs in fields like drug delivery and 3D-printing for tissue engineering. Ultimately, by unlocking critical chemical information, this proposal will pave the way for groundbreaking polymer research in Peru. This will elevate the local capacity in the field of macromolecular dynamics, with a focus on future in vivo applications.
Steady state free precession relaxation mapping with deep learning in high-resolution NMR spectroscopy
Description: Steady-State Free Precession (SSFP) in Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful technique for acquiring high-resolution spectra. However, accurately determining longitudinal (T1) and transverse (T2) spin relaxation times from SSFP data presents a significant challenge due to the complex interplay between signal intensity and numerous experimental parameters. To address this challenge, this research proposes a novel deep learning (DL)-driven framework for directly mapping simultaneous T1 and T2 values from SSFP datasets. This approach overcomes the limitations of traditional methods, such as inversion recovery and Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence, by employing deep learning routines to model spin dynamics and accurately map relaxation times. These architectures will be trained to learn the complex relationships between experimental parameters (flip angle (θ), RF pulse duration, repetition time (TR), echo time (TE)), SSFP signal intensities, and the underlying relaxation times (T1 and T2). Furthermore, this DL-based approach offers several key advantages, including enhanced accuracy and efficiency, improved robustness against experimental noise and artifacts, and increased flexibility for adapting to diverse SSFP pulse sequences and experimental conditions. Consequently, this research has the potential to significantly advance NMR spectroscopy by enabling more accurate and efficient relaxation time measurements using SSFP, thereby accelerating research across diverse fields, including biomolecular NMR, materials science, and metabolomics.
Development of filtered molecular protocols to boost the sensitivity in NMR spectroscopy
Description: The objective of this project will be designing the low-field (LF) NMR spectroscopy for in vivo applications. For this purpose, dynamic nuclear polarization (DNP) approaches will be used to enhance the NMR sensitivity and substantially reduce the experimental time. In turn, the technology developed will provide a unique opportunity permitting real-time in vivo toxicity screening, using movable and economical LF-NMR systems, in combination with cells and small organisms. The developed approach will have the potential to detect and monitor metabolic impacts of stress, as well as explain the biochemical pathways impacted, essential for understanding, the evolution of tumoral activities. Therefore, the scientific technology developed in this project should be a critical step towards the next generation of toxicity screening methods, that are desperately needed to unravel toxic impacts at the molecular level, well integrating with NMR Centre at the University of Toronto who have pioneered high field in vivo NMR screening approaches.
Development and application of advanced NMR protocols in environmental analytical chemistry.
Description: This internship project deals with the investigation of intermolecular interactions between agrochemicals towards natural organic matter and small living organisms by advanced NMR approaches. To reach this goal a range of state-of-the-art NMR-based binding methods will be used, among them, Saturation Transfer Difference (STD) NMR, 2D-NOESY and Waterlogsy. To provide binding orientation and identify receptors Reverse Heteronuclear (RH)-STD NMR and Saturation Transfer Double Difference (STDD) spectroscopy will be also employed. In addition to the NMR, theoretical approaches (molecular docking) will be used to provide an additional level of detail regarding the binding mechanisms for these species, and support the experimental results previously obtained. Finally, the binding interactions and influence of agrochemicals towards small living organisms will be investigated both in situ and in-vivo. For these 2 unique technologies only located at the Environmental NMR Center in Canada will be used. For low stress binding studies and bioaccumulation studies in vivo flow cells in which the organisms can be kept alive indefinitely. However, this approach is limited to studying to only the solution components. To study all phases in the living organisms (solids (shell), gels (tissue), liquid (blood) a Comprehensive MultiPhase (CMP) probe head developed in the Canadian Center will be used. This technology is not available in Brazil. Therefore, this internship program will supply to the candidate a solid, advanced and complete formation in NMR spectroscopy applied to environmental research, leading to contribute with innovative alternative solutions for actual and relevant environmental challenges.