NTA-functionalized poly(L-lysine)-g-poly(ethylene glycol): A polymeric interface for binding and studying 6xHis-tagged proteins
- Conference Paper
In this paper, a novel graft copolymer, poly-(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) with part of the PEG chains carrying a terminal nitrilotriacetic acid group (NTA) was synthesized. Through electrostatic interactions, these polycationic graft co-polymers assemble spontaneously from aqueous solution onto negatively charged surfaces, forming polymeric monolayers that present NTA groups at controlled surface densities on a highly PEGylated background. The NTA-functionalized PLL-g-PEG surfaces proved to be highly resistant to nonspecific adsorption in contact with human serum while allowing the specific and reversible surface binding of GFPuv-6His and beta-lactamase-6His in native conformation. Micropatterns consisting of NTA-functionalized PLL-g-PEG in a background of PLL-g-PEG were produced using the "molecular assembly patterning by lift-off" technique. Exposure to Ni 2+ and GFPuv-6His resulted in a protein pattern of excellent contrast as judged by fluorescence microscopy. Furthermore, optical waveguide lightmode spectroscopy (OWLS) and a miniature fiber optic absorbance spectrometer (FOAS) were combined as affinity and catalytic biosensor to monitor in situ and quantitatively the amount of immobilized beta-lactamase-6His and to determine the activity of the immobilized enzyme. The NTA-functionalized PLL-g-PEG surface is considered to be a promising sensor platform for binding 6xHis-tagged proteins thanks to the simplicity and cost-effectiveness of the surface modification protocol, high specificity and nearly quantitative reversibility of the protein binding, and the potential to fabricate microarrays of multiple capture molecules. Show more
Book titleProceedings of the 2005 IEEE Engineering in Medicine and Biology 27th Annual Conference
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