Highly Cross-Linked and Biocompatible Polyphosphazene-Coated Superparamagnetic Fe₃O₄ Nanoparticles for Magnetic Resonance Imaging

Highly cross-linked and biocompatible poly­(cyclotriphosphazene-<i>co</i>-4,4′-sulfonyldiphenol) (PZS) were used to directly coat hydrophilic superparamagnetic Fe₃O₄ nanoparticles by a facile but effective one-pot polycondensation. The obtained core–shell Fe₃O₄@PZS nanohybrids were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) and X-ray diffraction spectra. Interesting, the size and T₂ relaxivity of Fe₃O₄@PZS increased with increasing the mass ratio of Fe₃O₄ to PZS. All these nanohybrids could be internalized by HeLa cells but show negligible cytotoxicity. The PZS layer slowly degraded into less dangerous forms such as 4,4′-sulfonyldiphenol, phosphate and ammonia at neutral or acid atmosphere. Considering their excellent water dispersibility, colloidal and chemical stability, magnetic manipulation, and magnetic resonance imaging (MRI) properties, Fe₃O₄@PZS nanohybrids have great potential in MRI diagnosis of cancer

Facile Synthesis of Superparamagnetic Fe₃O₄@polyphosphazene@Au Shells for Magnetic Resonance Imaging and Photothermal Therapy

Multifunctional nanoparticles were prepared by directly welding superparamagnetic Fe₃O₄ nanoparticles and Au shells together with highly cross-linked polyphosphazene as “glue” in a facile but effective way. The as-prepared particles can simultaneously take advantages of both magnetization of Fe₃O₄ core for magnetic resonance imaging diagnosis and strong near-infrared absorption of Au nanoshell for photothermal therapy

Golden Single-Walled Carbon Nanotubes Prepared Using Double Layer Polysaccharides Bridge for Photothermal Therapy

Golden single-walled carbon nanotubes (SWNTs) were prepared by growing gold nanoparticles onto the bilayer polysaccharide functionalized SWNTs. The layer-by-layer self-assembly of sodium alginate and chitosan on SWNTs provided an ideal surface with high density of active metal-binding groups such as amino and carboxylic acid groups, and then an approach of seed growth was adopted to facilitate the formation of gold nanoparticles coated SWNTs. The resulting golden SWNT hybrids have good water dispersibility and biocompatibility and tend to enter cancer cells. Interestingly, they have an enhanced NIR absorption and effectively transfer NIR laser into heat. The material can quickly cause localized hyperthermia, resulting in rapid cell death, and therefore appears to act as a highly effective photothermal converter for cancer ablation

Dual-Responsive Controlled Drug Delivery Based on Ionically Assembled Nanoparticles

Ionically assembled nanoparticles (INPs) have been formed from poly­(ionic liquid-<i>co</i>-<i>N</i>-isopropylacrylamide) with deoxycholic acid through electrostatic interaction. The structure and properties of the INPs were investigated by using ¹H NMR, Fourier transform infrared (FTIR), transmission electron microscopy (TEM), dynamic light scattering (DLS), and so on. Due to pH-responsive deoxycholic acid (p<i>K</i>_a = 6.2) and thermo responsive <i>N</i>-isopropylacrylamide included in the ionic complex, the INPs exhibit highly pH and thermal dual-responsive properties. The potential practical applications as drug delivery carriers were demonstrated using doxorubicin (DOX) as a model drug. With a lower pH (pH 5.2) and higher temperature (above 37 °C), structural collapse of the INPs occurred as well as release of DOX owing to protonated DA departure from the INPs and a lower LCST (lower critical solution temperature) at the pathological conditions. The result shows that 80% of DOX molecules were released from INPs within 48 h at pH 5.2, 43 °C, but only 30% of the drug was released within 48 h at 37 °C and pH 7.4. Moreover, drug-loaded INPs exhibit an inhibitory effect on cell growth