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

ABSTRACT

Fe₃O₄/Ag core/shell nanoparticles functionalized with the free amino (NH₂) functional groups (Fe₃O₄/Ag-NH₂) 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_NP:V_AB ratio, where V_NP and V_AB 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_NP:V_AB was increased from 2:1 to 100:1, and it gradually reached the saturated state at an efficiency of 95%, as the V_NP:V_AB was equal to 300:1. The bioactivity of the abovementioned conjugation product (denoted by Fe₃O₄/Ag-antiCD34) was evaluated in an experiment for the collection of stem cells from bone marrow samples.

KEYWORDS:

• Fe₃O₄/Ag core/shell nanoparticles
• antibody conjugation
• CD34+ stem cells
• magnetic separation

Acknowledgments

The authors would like to thank Center for Materials Science, Faculty of Physics, Hanoi University of Science, Vietnam National University, and VINMEC Research Institute of Stem cell and Gene Technology for the provision of necessary equipment and bone marrow samples.

Additional information

Funding

This work was supported by the Vietnam National University under Grand number [QG.16.04].