DNA intracellular delivery into 3T3 cell line using fluorescence magnetic ferumoxide nanoparticles

Gene delivery is a widespread strategy in current experimental medicine. In this work, we report a method
for low-toxic intracellular DNA vector delivery and post transfection localisation of this vector in mouse
embryonic fibroblast cell lines. The surface of modified ferumoxide nanoparticles conjugated with Rhodamine
B isothiocyanate (FeNV-Rh) was modified with linear polyethyleneimine and medium molecular
weight chitosan to increase Accelerated Sensor of Action Potentials DNA vector adhesion. The size of the
FeNV-Rh/DNA transfection complex was studied using dynamic light scattering (DLS) and scanning
electron microscopy (SEM) techniques. The transfection complex internalisation of plasmid expression
and FeNV-Rh, and stability of rhodamine fluorescence in intracellular space were observed at time periods
6, 12, 24 and 48 h post transfection. Results showed high transfection complex intracellular
biocompatibility—cell viability after Rh-MNP labelling was higher than 97% 24 h after transfection, and
higher than 95% after the next 24 h. Selective FeNV-Rh localisation in the lysosomes was quantified.
More than 82% of nanoparticles were localised in the lysosomes 12 h post transfection and 94% of
lysosomes had a significant and long-term deposit of nanoparticles. DNA vector expression was visible in
>65% of the cells and precise protein localisation on the cell membrane was confirmed using confocal
microscopy.