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2Q NMR of (2)H2O ordering at solid interfaces
Tatiana V Krivokhizhina1, R J Wittebort1
1Department of Chemistry, 2320 S. Brook St., University of Louisville, Louisville, KY 40208, USA.
Journal of Magnetic Resonance (San Diego, Calif. : 1997)
|April 10, 2014
Summary
Multiple-quantum Nuclear Magnetic Resonance (NMR) quantifies solvent ordering. This study developed a method to analyze deuterium (2H2O) ordering in hydrated biological tissues, revealing increased water ordering in stretched elastin.
Area of Science:
- Biophysics
- Nuclear Magnetic Resonance (NMR) Spectroscopy
- Materials Science
Background:
- Solvent ordering at interfaces is crucial for understanding various physical and biological processes.
- Multiple-quantum NMR offers a powerful technique for probing molecular ordering and dynamics.
- Quantitative analysis of deuterium (2H2O) ordering requires precise control over experimental conditions and data interpretation.
Purpose of the Study:
- To develop and validate a method for quantitative studies of deuterium (2H2O) solvent ordering at interfaces using multiple-quantum NMR.
- To accurately measure and analyze double-quantum (2Q) buildup curves, accounting for relaxation and residual couplings.
- To apply the developed method to investigate water ordering in hydrated biological tissues like collagen and elastin.
Main Methods:
- Extension of a pulse sequence with absorption mode detection for coherence separation by order.
- Measurement of relaxation times, specifically the 2Q filtered T2, to aid in data analysis.
- Analysis of 2Q buildup curves, incorporating relaxation and residual coupling distributions for quantitative interpretation.
Main Results:
- The developed method successfully extracted coupling constants from (2H2O) hydrated collagen, matching results from conventional 1D experiments.
- The ratio of 2Q to 1Q signals in hydrated collagen was consistent with theoretical predictions.
- Application to (2H2O) hydrated elastin revealed a significant increase in the 2Q signal upon mechanical stretching, attributed to enhanced ordered water fraction, with minimal changes in residual coupling and T2.
Conclusions:
- The enhanced multiple-quantum NMR methodology provides a robust approach for quantitative solvent ordering studies.
- The findings demonstrate that mechanical stretching of elastin significantly increases the fraction of ordered water molecules.
- This technique is valuable for characterizing interfacial water dynamics in complex biological systems.
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