Surface-initiated atom transfer radical polymerization of cationic corona on iron oxide nanoparticles for magnetic sorting of macrophages.

Ovalbumin-incorporated antigen carriers were prepared by surface-initiated atom transfer radical polymerization (SI-ATRP) of iron oxide nanoparticles for magnetic sorting of antigen-presenting cells. Iron oxide nanoparticles were surface-decorated with cationic shells by SI-ATRP, and the primary amines on the surface were further tri-methylated. Surface decoration of the nanoparticles was characterized by Fourier transform infrared spectroscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and transmission electron microscopy with energy-dispersive spectrometry. Ovalbumin-loaded nanoparticles showed higher incorporation in comparison to non-decorated nanoparticles, and the loaded ovalbumin was released faster at low pH than at neutral pH. Ovalbumin-loaded nanoparticles were endocytosed by macrophages, and macrophages with nanoparticles were easily harvested by magnetic separation. Magnetically sorted macrophages showed higher release of cytokines including TNF-α, MIP-1α, and IL-1ß than unsorted macrophages. These results suggest that ovalbumin-loaded nanoparticles can potentially increase the efficiency of immune therapy during the antigen-presenting pathway.

Coaxial Hydro-Nanofibrils for Self-Assembly of Cell Sheets Producing Skin Bilayers.

Bilayered cell sheets were fabricated with coaxial hydro-nanofibrils for three-dimensional (3D) cultivation in a biomimetic environment. Polycaprolactone (PCL) was electrospun and hydrolyzed to release fragmented nanofibrils (NF) in an alkaline condition. Methacrylated gelatin (GelMA) was adsorbed and phototethered on the surface of the fibrils to prepare coaxial NF composed of hydrophilic shells and hydrophobic cores. GelMA layers on the NF were characterized by X-ray photoemission spectroscopy, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The GelMA showed higher decoration level on NF compared to that on native gelatin. GelMA-decorated NF significantly enhanced cell proliferation rate and phenotypic expression of human dermal fibroblasts when spontaneous formation of cell sheets was observed for 7 days. HaCaT cells were layered on top of the fibroblast sheets and further cultivated in air-water interfaces to prepare bilayered skin sheets. After 21 days of incubation, the top layers of the bilayered sheets showed higher expression of pan-keratin, and the dermal cells showed higher proliferation in the GelMA-decorated NF.

Epidermal growth factor (EGF) fragment-guided anticancer theranostic particles for pH-responsive release of doxorubicin.

EGF fragment (EGFfr) and doxorubicin were chemically co-decorated on single magnetic nanoparticles (MNPs) for concomitant cancer targeting and treatment. Magnetic nanoparticles were prepared by the precipitation of ferric chloride hydrates in an ammonia solution and subsequent surface-functionalization with amines. The terminal thiol group of the EGF fragment was first conjugated to surface amines of the MNPs using a heterofunctional crosslinker, and doxorubicin was sequentially conjugated to the MNPs via a hydrazone linker, where the degree of subsitution of the surface amines to EGFfr was varied from 1% to 40%. The decorated doxorubicin showed clear pH-dependency in the release profile, and doxorubicin showed fast release at pH 5.0 in comparison to pH 7.4. The EGF-decorated MNPs were tested for differential cellular uptakes against EGF overexpressing cells (A549), and the uptake levels gradually increased to 10% and saturated, which was quantified by ICP-OES. Internalized doxorubicin was also visualized by confocal microscopy, and A549 cells with EGF-decorated MNPs with EGF decoration showed higher fluorescence intensity of doxorubicin than those with non-decorated MNPs. Anti-cancer activity of the MNPs was compared at various concentrations of doxorubicin and EGFfr. Decoration of EGFfr significantly increased the anti-cancer activity of doxorubicin-incorporated MNPs in A549 cells; however, EGFfr alone did not affect the viability of the cells. Thus, we concluded that MNPs with optimized EGFfr and doxorubicin ratios showed higher targeting and drug payload against EGF receptor overexpressing cancer cells.