Plasmid-DNA Delivery by Covalently Functionalized PEI-SPIONs as a Potential 'Magnetofection' Agent.

Nanoformulations for delivering nucleotides into cells as vaccinations as well as treatment of various diseases have recently gained great attention. Applying such formulations for a local treatment strategy, e.g., for cancer therapy, is still a challenge, for which improved delivery concepts are needed. Hence, this work focuses on the synthesis of superparamagnetic iron oxide nanoparticles (SPIONs) for a prospective "magnetofection" application. By functionalizing SPIONs with an active catechol ester (CafPFP), polyethyleneimine (PEI) was covalently bound to their surface while preserving the desired nanosized particle properties with a hydrodynamic size of 86 nm. When complexed with plasmid-DNA (pDNA) up to a weight ratio of 2.5% pDNA/Fe, no significant changes in particle properties were observed, while 95% of the added pDNA was strongly bound to the SPION surface. The transfection in A375-M cells for 48 h with low amounts (10 ng) of pDNA, which carried a green fluorescent protein (GFP) sequence, resulted in a transfection efficiency of 3.5%. This value was found to be almost 3× higher compared to Lipofectamine (1.2%) for such low pDNA amounts. The pDNA-SPION system did not show cytotoxic effects on cells for the tested particle concentrations and incubation times. Through the possibility of additional covalent functionalization of the SPION surface as well as the PEI layer, Caf-PEI-SPIONs might be a promising candidate as a magnetofection agent in future.

Enzyme-Powered Porous Micromotors Built from a Hierarchical Micro- and Mesoporous UiO-Type Metal-Organic Framework.

Here, we report the design, synthesis, and functional testing of enzyme-powered porous micromotors built from a metal-organic framework (MOF). We began by subjecting a presynthesized microporous UiO-type MOF to ozonolysis, to confer it with mesopores sufficiently large to adsorb and host the enzyme catalase (size: 6-10 nm). We then encapsulated catalase inside the mesopores, observing that they are hosted in those mesopores located at the subsurface of the MOF crystals. In the presence of H2O2 fuel, MOF motors (or MOFtors) exhibit jet-like propulsion enabled by enzymatic generation of oxygen bubbles. Moreover, thanks to their hierarchical pore system, the MOFtors retain sufficient free space for adsorption of additional targeted species, which we validated by testing a MOFtor for removal of rhodamine B during self-propulsion.