Magnetically Induced Thermal Effects on Tobacco Mosaic Virus-Based Nanocomposites for a Programmed Disassembly of Protein Cages.

Protein cages are promising tools for the controlled delivery of therapeutics and imaging agents when endowed with programmable disassembly strategies. Here, we produced hybrid nanocomposites made of tobacco mosaic virus (TMV) and magnetic iron oxide nanoparticles (IONPs), designed to disrupt the viral protein cages using magnetically induced release of heat. We studied the effects of this magnetic hyperthermia on the programmable viral protein capsid disassembly using (1) elongated nanocomposites of TMV coated heterogeneously with magnetic iron oxide nanoparticles (TMV@IONPs) and (2) spherical nanocomposites of polystyrene (PS) on which we deposited presynthesized IONPs and TMV via layer-by-layer self-assembly (PS@IONPs/TMV). Notably, we found that the extent of the disassembly of the protein cages is contingent upon the specific absorption rate (SAR) of the magnetic nanoparticles, that is, the heating efficiency, and the relative position of the protein cage within the nanocomposite concerning the heating sources. This implies that the spatial arrangement of components within the hybrid nanostructure has a significant impact on the disassembly process. Understanding and optimizing this relationship will contribute to the critical spatiotemporal control for targeted drug and gene delivery using protein cages.

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.