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

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.