Nonhomogeneous Silica Promotes the Biologically Induced Delivery of Metal Ions from Silica-Coated Magnetic Nanoparticles

Herein we report the endocytosis of magnetic nanoparticles of two different transition metal ferrites, which are coated with silica. The variation in the cytotoxicity results, which correlate with the metal ions from the magnetic cores, stems from the inhomogeneity of the silica shell and consequent partial degradation of the nanoparticles once loaded into the endosomes of Caco-2 cells

Magnetic Silica Nanoparticle Cellular Uptake and Cytotoxicity Regulated by Electrostatic Polyelectrolytes–DNA Loading at Their Surface

Magnetic silica nanoparticles show great promise for drug delivery. The major advantages correspond to their magnetic nature and ease of biofunctionalization, which favors their ability to interact with cells and tissues. We have prepared magnetic silica nanoparticles with DNA fragments attached on their previously polyelectrolyte-primed surface. The remarkable feature of these materials is the compromise between the positive charges of the polyelectrolytes and the negative charges of the DNA. This dual-agent formulation dramatically changes the overall cytotoxicity and chemical degradation of the nanoparticles, revealing the key role that surface functionalization plays in regulating the mechanisms involved