Capillary-Inserted Rotor Design for HRµMAS NMR-Based Metabolomics on Mass-Limited Neurospheres

• Main Authors: Nghia Tuan Duong, Masanori Yamato, Masayuki Nakano, Satoshi Kume, Yasuhisa Tamura, Yosky Kataoka, Alan Wong, Yusuke Nishiyama
• Format: Article
• Language: English
• Published: MDPI AG 2017-08-01
• Series: Molecules
• Subjects: NMR; metabolomics; metabolites; HRµMAS; capillary-inserted rotor; mass-limited neurospheres
• Online Access: https://www.mdpi.com/1420-3049/22/8/1289

Nuclear magnetic resonance (NMR) spectroscopy is a powerful analytical technique and has been widely used in metabolomics. However, the intrinsic low sensitivity of NMR prevents its applications to systems with limited sample availabilities. In this study, a new experimental approach is presented to analyze mass-scarce samples in limited volumes of less than 300 nL with simple handling. The sample is loaded into the glass capillary, and this capillary is then inserted into a Kel-F rotor. The experimental performance of the capillary-inserted rotor (capillary-insert) is investigated on an isotropic solution of sucrose by the use of a high-resolution micro-sized magic angle spinning (HRµMAS) probe. The acquired NMR signal’s sensitivity to a given sample amount is comparable or even higher in comparison to that recorded by the standard solution NMR probe. More importantly, this capillary-insert coupled with the HRµMAS probe allows in-depth studies of heterogeneous samples as the MAS removes the line broadening caused by the heterogeneity. The NMR analyses of mass-limited cultured neurospheres have been demonstrated, resulting in high quality spectra where numerous metabolites are unambiguously identified.