NMR Nanoparticle Diffusometry in Hydrogels: Enhancing Sensitivity and Selectivity

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• 作者：Daan W. de Kort ; John P. M. van Duynhoven ; Freek J. M. Hoeben ; Henk M. Janssen ; Henk Van As
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：September 16, 2014
• 年：2014
• 卷：86
• 期：18
• 页码：9229-9235
• 全文大小：341K
• ISSN：1520-6882

文摘

From the diffusional behavior of nanoparticles in heterogeneous hydrogels, quantitative information about submicron structural features of the polymer matrix can be derived. Pulsed-gradient spin鈥揺cho NMR is often the method of choice because it measures diffusion of the whole ensemble of nanoparticles. However, in ¹H diffusion-ordered spectroscopy (DOSY), low-intensity nanoparticle signals have to be separated from a highly protonated background. To circumvent this, we prepared ¹⁹F labeled, PEGylated, water-soluble dendritic nanoparticles with a ¹⁹F loading of 鈭? wt % to enable background free ¹⁹F DOSY experiments. ¹⁹F nanoparticle diffusometry was benchmarked against ¹H diffusion-T₂ correlation spectroscopy (DRCOSY), which has a stronger signal separation potential than the commonly used ¹H DOSY experiment. We used bootstrap data resampling to estimate confidence intervals and stabilize 2D-Laplace inversion of DRCOSY data with high noise levels and artifacts, allowing quantitative diffusometry even at low magnetic field strengths (30 MHz). The employed methods offer significant advantages in terms of sensitivity and selectivity.