Development of Fe₃O₄/Ag core/shell-based multifunctional immunomagnetic nanoparticles for isolation and detection of CD34+ stem cells

Abstract

FeO/Ag core/shell nanoparticles functionalized with the free amino (NH) functional groups (FeO/Ag-NH) were conjugated with fluorescent electron coupled dye (ECD)-antiCD34 antibody using the 1-ethyl-3-(3'-dimethyl-aminopropyl) carbodiimide (EDC) catalyst (ECD - Electron Coupled Dye or R Phycoerythrin-Texas Red is a fluorescent organic dye attached to the antibody). The characteristic fluorescence of ECD in the antibody was investigated and was used as a good indicator for estimating the percentage of the antibodies that were successfully conjugated with the nanoparticles. The conjugation efficiency was found to increase depending on the V:V ratio, where V and V are the volumes of the nanoparticle solution (concentration of 50 ppm) and the as-purchased antibody solution, respectively. The conjugation efficiency rapidly increased from approximately 18% to approximately 70% when V:V was increased from 2:1 to 100:1, and it gradually reached the saturated state at an efficiency of 95%, as the V:V was equal to 300:1. The bioactivity of the abovementioned conjugation product (denoted by FeO/Ag-antiCD34) was evaluated in an experiment for the collection of stem cells from bone marrow samples.

Multifunctional Silver Nanoparticles: Synthesis and Applications

“…Those results also imply that the core-shell nanoparticles combine the plasmonic and magnetic properties, which can be used together in the applications of the multifunctional silver nanoparticles. The Fe 3 O 4 -Ag composites, as expected, show the same picture [30,31].…”

“…Multifunctional nanoparticles have attracted much interest because of their ability to combine various properties, such as electronic, optical, catalytic, surface enhance, and magnetic properties, by using the combination of individual nanoparticles and/or functionalize the core nanoparticles with appropriate agents [28][29][30][31]15]. Combining of individual nanoparticles enhances functionality or creates new properties compared to those of individual nanoparticles.…”

“…It also can be act as a very thin protection layer of the magnetic core, and then silver ion was observed and reduced on the surface of the silica layer to form plasmonic-magnetic nanocomposites as can be seen in Figure 2b [29]. In comparison, Fe 3 O 4 magnetic nanoparticles are functionalized with 3-aminopropyltriethoxysilance (APTES) and silver nanoparticles are reduced on the amino (-NH 2 ) groups of this functionalized layer to form multifunctional silver nanocomposites, which have a one-atom thin layer of Si-O on the surface of Fe 3 O 4 core as can be seen in Figure 2c [30,31].…”

“…Magnetic nanoparticles can also be directly functionalized with APTES without coating with silica layer [30,31]. They were dispersed in ethanol before adding the APTES and NH 4 OH with assistance of ultrasound.…”

“…The HRTEM images of plasmonic-magnetic Fe 3 O 4 @SiO 2 -Ag and Fe 3 O 4 -Ag composites are shown in Figure 4 [29][30][31], where the Figure 4a shows the image of magnetic core. Figures 4b and 4b1 show the TEM and HRTEM image of the magnetic nanoparticles coated with silica Fe 3 O 4 @SiO 2 , respectively, while the Figure 4c shows the final composite image after Ag nanoparticles were reduced on the amino groups NH 2 -around the magnetic core.…”