Specific Adsorption of Histidine-Tagged Proteins on Silica Surfaces Modified with Ni2+/NTA-Derivatized Poly(ethylene glycol)

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• 作者：Eunah Kang ; Jin-Won Park ; Scott J. McClellan ; Jong-Mok Kim ; David P. Holland ; Gil U. Lee ; Elias I. Franses ; Kinam Park ; David H. Thompson
• 刊名：Langmuir
• 出版年：2007
• 出版时间：May 22, 2007
• 年：2007
• 卷：23
• 期：11
• 页码：6281 - 6288
• 全文大小：166K
• 年卷期：v.23,no.11(May 22, 2007)
• ISSN：1520-5827

文摘

Silica surfaces modified with nitrilotriacetic acid (NTA)-polyethylene glycol (PEG) derivatives were used to immobilizehexahistidine-tagged green fluorescent protein (His₆-GFP), biotin/streptavidin-AlexaFluor555 (His₆-biotin/SA-AF),and gramicidin A-containing vesicles (His₆-gA). Three types of surface-reactive PEG derivatives-NTA-PEG3400-Si(OMe)₃, NTA-PEG3400-vinylsulfone, and mPEG5000-Si(OMe)₃ (control)-were grafted onto silica and tested fortheir ability to capture His₆-tag species via His₆/Ni²⁺/NTA chelation. The composition and thicknesses of the PEG-modified surfaces were characterized using X-ray photoelectron spectroscopy, contact angle, and ellipsometry. Proteincapture efficiencies of the NTA-PEG-grafted surfaces were evaluated by measuring fluorescence intensities of thesesurfaces after exposure to His₆-tag species. XPS and ellipsometry data indicate that surface adsorption occurs viaspecific interactions between the His₆-tag and the Ni²⁺/NTA-PEG-grafted surface. Protein immobilization was mosteffective for NTA-PEG3400-Si(OMe)₃-modified surfaces, with maximal areal densities achieved at 45 pmol/cm² forHis₆-GFP and 95 fmol/cm² for His₆-biotin/SA-AF. Lipid vesicles containing His₆-gA in a 1:375 gA/lipid ratio couldalso be immobilized on Ni²⁺/NTA-PEG3400-Si(OMe)₃-modified surfaces at 0.5 mM total lipid. Our results suggestthat NTA-PEG-Si(OMe)₃ conjugates may be useful tools for immobilizing His₆-tag proteins on solid surfaces toproduce protein-functionalized surfaces.