Using Magnetic Resonance Imaging to Study Enzymatic Hydrogelation

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• 作者：Weijuan Wang ; Junchao Qian ; Anming Tang ; Linna An ; Kai Zhong ; Gaolin Liang
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：June 17, 2014
• 年：2014
• 卷：86
• 期：12
• 页码：5955-5961
• 全文大小：434K
• 年卷期：v.86,no.12(June 17, 2014)
• ISSN：1520-6882

文摘

Herein, we report, for the first time, the use of MRI methods to study enzymatic hydrogelation. Supramolecular hydrogels have been exploited as biomaterials for many applications. However, behaviors of the water molecules encapsulated in hydrogels have not been fully understood. In this work, we designed a precursor 1 which could self-assemble into nanofibers and form hydrogel I (gel I) upon the catalysis of phosphatase. The differences of mechanic property, pore size, water diffusion rate, and magnetic resonance relaxation times T₁ and T₂ of gel I containing different concentrations of 1 were systematically studied and analyzed. T₁, T₂, and diffusion-weighted ¹H MR images from gel I phantoms were obtained at 9.4 T. Analyses of the MRI data uncovered how the density of the nanofiber networks affects the relaxation behaviors of the water protons encapsulated in such hydrogels. Rheological analyses and cryo-TEM observations showed increased gel elasticities with increased concentrations of 1 while the pore sizes of gel I decreased. This also resulted in an increase in the proton relaxation rate (i.e., shortened T₁, T₂, and apparent diffusion coefficient (ADC)) for the water encapsulated in the hydrogel. With MRI, our study provides a new in vitro method to potentially mimic and study in vivo diseases that involve fibrous aggregates.