DEVELOPMENT OF TWO NEW APPROACHES FOR SURFACE IMPRINTING OF PROTEINS OVER MAGNETIC NANOPARTICLES

Natural antibodies or receptors bind their targets via multiple non-covalent interactions in a synergistic manner which offer high affinity and great specificity. Here we demonstrate two new approaches for surface imprinting of proteins over magnetic nanoparticles to fabricate artificial binding pockets that incorporate different types of interactions.

(1) Employing human apurinic/apyrimidinic endonuclease/redox effector factor 1 (APE1) as a model protein, a monolayer of template molecules was first assembled onto the surface of avidin-modified silica coated magnetic nanoparticles (SiMNP@AVD) by formation of a stable complex with the avidin. Then dopamine was allowed to polymerize around the complex to further form a binding pocket. The obtained nanocomposites could not only specifically recognize and capture the target protein from complex biological samples, but also efficiently inhibit the enzymatic activity of the protein, which could not be achieved by either the biological ligand (avidin) itself or the polydopamine polymer alone. Moreover, the bound protein could be reversibly released from the binding pockets with high activity under mild conditions. These features offer great potential to serve as protein receptors or enzyme nano-inhibitors for cancer treatment.

(2) A novel “sequential imprinting” approach has been developed which combines two different types of imprinting reactions. The first step is based on a simple self-polymerization of dopamine on the surface of Fe₃O₄@SiO₂ nanoparticles. Then a secondary imprinting step was performed by addition of organic boronic acid molecules. The method was applied to imprinting two different protein templates: DNase I (deoxyribonuclease I) and APE1. The obtained artificial receptor nanoparticles were successfully used for extraction, purification and recover of the two proteins from complex biological samples.

Acknowledgment: The work was supported by the National Natural Science Foundation of China (21775009, 21575008).

References

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