Intracellular Delivery of siRNA by Polycationic Superparamagnetic Nanoparticles

Table 1

Properties of the functionalized core-shell NP of the present study.

Particle species	Number-average hydrodynamic diameter; (nm)^a	Polymer content; (wt%)^b	Saturation magnetization; (emu/g of magnetite)^c
PHMBG-M/SiO2	160±11	55–60	80–89
PEI-M/SiO2	240±16	57–60	80–90

aDynamic light scattering experiments were performed with a Brookhaven BI-200SM light scattering system (Brookhaven Instruments Corporation, Austin, TX) at a measurement angle of 90°. Particles dispersed in aqueous media (pH adjusted by 1 M NaOH or HCl) were filtered with a 0.45 μm syringe filter prior to the DLS tests. The particles were dispersed with sonication in 10 mM KCl aqueous solution at approximately 0.05 wt% concentrations, and the pH of the nanoparticle suspensions was adjusted by adding 1 M HCl or NaOH aqueous solutions. Hydrodynamic diameter was measured in 10 mM KCl. bThe polymer and magnetite contents were found from elemental analyses and TGA. cSaturation magnetization was found from SQUID measurements and divided per gram of iron (as found from elemental analysis) and then recalculated per gram of magnetite, assuming Fe₃O₄ structure of magnetite. No assumptions were required for the phase composition of the core material, as it had been previously proven to consist of magnetite.