Dynamic cross-linking effect of Mg2+ to enhance sieving properties of low-viscosity poly(vinylpyrrolidone) solutions for microchip electrophoresis of proteins

Mohamad Reza Mohamadi, Noritada Kaji, Anabu Tokeshi, Yoshinobu Baba

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

We report a dynamic cross-linking effect of Mg2+ that enhances the sieving properties of low-viscosity poly-(vinylpyrrolidone) (PVP) solutions. A low-viscosity PVP solution was applied to nondenaturing microchip electrophoresis of protein samples using microchips made of poly(methyl methacrylate). The separation resolution of nondenatured protein markers in 1.8% PVP solution was improved by adding 1-20 mM MgCl2. We studied the effect of the ratio of cross-linking agent on mobility of protein samples and showed that protein retardation (In μ/μ0) is correlated with the ratio of cross-linking agent to PVP ([cMg2+/cPVP]) as In μ/μ0 = A′[cMg2+ /cPVP] b′. A′ was related to the protein radius (R), and b′ was found to be 0.72 for proteins with R = 2.4 nm and 0.82 for proteins with R = 1.85 nm. A structural study of PVP in semidilute solutions using dynamic light scattering showed that incremental increases of Mg2+ ion concentration from 5 to 20 mM in 1.8% PVP solution increased the hydrodynamic radius of PVP polymers by 20%.

Original languageEnglish
Pages (from-to)312-316
Number of pages5
JournalAnalytical Chemistry
Volume80
Issue number1
DOIs
Publication statusPublished - Jan 1 2008
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry

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