Quantitative Analysis of Molecular Transport across Liposomal Bilayer by J-Mediated 13C Overhauser Dynamic Nuclear Polarization

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• 作者：Chi-Yuan Cheng ; Olga J.G.M. Goor ; Songi Han
• 刊名：Analytical Chemistry
• 出版年：2012
• 出版时间：November 6, 2012
• 年：2012
• 卷：84
• 期：21
• 页码：8936-8940
• 全文大小：241K
• 年卷期：v.84,no.21(November 6, 2012)
• ISSN：1520-6882

文摘

We introduce a new NMR technique to dramatically enhance the solution-state ¹³C NMR sensitivity and contrast at 0.35 T and at room temperature by actively transferring the spin polarization from Overhauser dynamic nuclear polarization (ODNP)-enhanced ¹H to ¹³C nuclei through scalar (J) coupling, a method that we term J-mediated ¹³C ODNP. We demonstrate the capability of this technique by quantifying the permeability of glycine across negatively charged liposomal bilayers composed of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG). The permeability coefficient of glycine across this DPPC/DPPG bilayer is measured to be (1.8 卤 0.1) 脳 10^鈥?1m/s, in agreement with the literature value. We further observed that the presence of 20 mol % cholesterol within the DPPC/DPPG lipid membrane significantly retards the permeability of glycine by a factor of 4. These findings demonstrate that the high sensitivity and contrast of J-mediated ¹³C ODNP affords the measurement of the permeation kinetics of small hydrophilic molecules across lipid bilayers, a quantity that is difficult to accurately measure with existing techniques.