Star-shaped magnetite@gold nanoparticles for protein magnetic separation and SERS detection

Abstract

A novel synthetic methodology for star shaped gold-coated magnetic nanoparticles is reported. The coating is performed in two steps: formation of gold nuclei at the surface of magnetite nanoparticles followed by growth of the gold nuclei into a complete star shaped shell. The star-shaped gold-coated magnetic nanoparticles thus obtained preserve the magnetic properties of the precursor magnetite nanoparticles, e.g. they can be easily separated with a magnet. In addition, the gold coating provides interesting optical properties while simultaneously allowing for biofunctionalization that may be advantageous for biological applications, such as (bio)detection via surface-enhanced Raman spectroscopy (SERS). As a proof-of-concept, a capping agent terminated with a nickel(II)-nitrilotriacetate group showing high affinity for histidine was used to modify the surface of the nanoparticles. The resulting star-shaped nanoparticles were used to selectively capture histidine-tagged maltose-binding protein from a crude cell extract. Finally, the performance of star shaped gold-coated magnetic nanoparticles as SERS platforms was demonstrated through the detection of Raman active dye (Astra Blue).

Synthesis of glucose-mediated Ag–γ-Fe2O3multifunctional nanocomposites in aqueous medium – a kinetic analysis of their catalytic activity for 4-nitrophenol reduction

“…1 These features render them the great potential for various applications like magnetic storage devices, 2 ferrofluids, 3 magnetic separation/biomolecular purification, 4 MRI contrast agents, targeted drug delivery, 5 hyperthermia, 6 immunoassay, 7 biosensing, 8 tissue regeneration, 9 cell sorting, 10 molecular interaction in live cells 11 and catalysis. 12 For most of the biomedical applications, it is desirable to make them water soluble containing biocompatible components.…”

Gold Nanostar Synthesis and Functionalization with Organic Molecules

“…A novel synthetic methodology for star-shaped gold-coated magnetic nanoparticles was reported in a paper published in 2014 in RCS Adv [ 105 ]. The coating was performed in two steps: formation of gold nuclei at the surface of magnetite nanoparticles followed by growth of the gold nuclei into a complete star-shaped shell.…”

Applications of Gold Nanostars: Nanosensing, Thermal Therapy, Delivery Systems

“…Star-shaped hybrid nanoparticles have been obtained by growing a star-shaped gold coating onto a magnetic core and have been tested for biodetection via magnetic separation and via SERS [ 19 ]. A capping agent terminated with a nickel-nitrilotriacetate group showing high affi nity to histidine was used to modify the surface of nanoparticles.…”