Intracellular translocation of superparamagnetic iron oxide nanoparticles encapsulated with peptide-conjugated poly(D,L lactide-co-glycolide)

In this study, we propose the use of iron oxide nanoparticle encapsulated with peptide-conjugated poly(D,L lactide-co-glycolide) (PLGA) as a potent intracellular carrier for diagnosis agent. The iron oxide $(γ‐Fe2O3)$ nanoparticles were prepared by a chemical coprecipitation method of ferric and ferrous ions in an alkali solution. Arg peptide (RRRRRRRRCK-FITC) were conjugated to the PLGA via a simple coupling reaction between maleimide-derivatized PLGA and thiol-terminated Arg peptide. The $γ‐Fe2O3$-PLGA-Arg-FITC nanoparticle was then prepared by an emulsification-diffusion technique. A confocal laser scanning microscopy revealed that the $γ‐Fe2O3$-PLGA-Arg-FITC nanoparticle was effectively adsorbed onto the membrane of stem cells and delivered into the nuclei without cytotoxicity. Magnetic properties of the $γ‐Fe2O3$-PLGA-Arg-FITC nanoparticle were observed by measuring the zero-field-cooled∕field-cooled magnetization and magnetic hysteresis loop using a superconducting quantum interference device magnetometer from $5K$ to $300K$⁠.