Biofunctional magnetic nanoparticles for protein separation with high specificity

Over the last decade there has been increased interest in "nanotechnology". A variety of supermolecular ensembles, multifunctional supermolecules, carbon nanotubes, and metal and semiconductor nanoparticles, nanowire, nanocube or nanosheet have been synthesized and proposed as the potential building blocks of optical, electronic and magnetic devices. Magnetic nanoparticles are one of the most promising fields in metal aggregates, because they response to magnetic control, allow information to be stored, and can be made to be biocompatible. Up to now, magnetic nanomaterials have been used in cell imaging, protein and cell separation and device fabrication. The synthesis for magnetic nanomaterials is based on colloidal thermal-chemical synthetic procedure or sol-gel process. Colloidal thermal-chemical synthetic procedure is our love-rich for it can provide sharp size distribution, good crystallinity, easy shape and size control. Typically, the colloidal thermal-chemical synthesis approaches involve either rapid injection of reagents into hot surfactant solution followed by aging at high temperature with a suitable time, or the mixing of reagents at a low temperature and slow heating under controlled conditions. Spherical iron platinum (FePt) nanoparticles, samarium cobalt (SmCo5) nanoparticles and samarium iron (Sm2Fe17) nanoparticles have been made by simultaneously reacting their constituent precursors in hot solution. The characterization of nanomaterials is aimed to elucidate structural features, interparticles interactions, and superstructure functionality. Direct imaging is the first step depending on various reliable, high resolution microscopies. Then surface analysis techniques, such as X-ray photoelectron and Fourier-transform infrared spectroscopies (XPS, XRF, Tof-SIMS and FTIR), provide tools to probe surface composition as well as to elucidate geometric features at surfaces. At last, surface plasmon spectroscopy (SPS), UV, lnfra-Red and magnetism give us an unprecedented ability to understand the complement properties. In terms of modification and appiication, our FePt nanoparticles was made water-soluble by connecting Nα,Nα-Bis(carboxymethyl)-L-Lysine (NTA) and Fe or Pt with 16-mercaptohexadecanoic acid as a linker, where Fe-S and Pt-S bonds are the key issue. Co@Fe2O3 and CoSm5.2@Fe2O3 have been made connect to NTA with dopamine (DA) as a linker, which is an amino acid that is believed to be responsible for the adhesive characteristics of mussel adhesive proteins (MAPs). Then, the strong bonding ability of dopamine to iron oxide shown in those experiments has been used to apply more bio-functional molecular to the iron oxide based particles' surface. The water soluble NTA-functionalized nanoparticles have been applied to separate 6xHis-tagged protein from the cell lysate after coordinating NTA with Ni2+ . The first example we demonstrate is the separation of green fluorescent protein (GFP). The separation results have demonstrated that the speciality and capacity of our systems are higher than the commercial magnet beads. Afterwards, other 6xHis-tagged proteins without fluorescence (e.g. a synaptic PDZ domain-containing protein GRIP (glutamate receptor interacting protein)) have also been tried to demonstrate the generality of our nanosystems