Intracellular protein delivery shows great promise in the treatment of various diseases. However, therapeutic applications of this method are limited by its low delivery efficiency and poor targeting ability. As one of most important drug delivery cargoes, Fe3O4 nanoparticles (nFe3O4) have attracted much attention for both therapeutic and diagnostic applications, especially for targeting drug delivery. To use nFe3O4 for protein delivery, a simple but effective modification of nFe3O4 is critical to attach proteins on its surface. In this work, by designing and synthesizing cationic poly(2‐(dimethylamino)ethyl methacrylate) (PDMA)‐grafted nFe3O4 via in situ atom transfer radical polymerization (ATRP), we demonstrate a simple solution to improve interactions between nFe3O4 and proteins. With the grafted PDMA on the surface, nFe3O4 exhibits not only significant enhancement in dispersibility and stability in aqueous phase, but also an excellent capability to attach negative‐charged proteins. Moreover, with the assistance of external magnetic field, PDMA‐grafted nFe3O4 can be used as a targetable vector to deliver proteins into specific cells. This work provides a novel platform based on cationic magnetite nanoparticles that can deliver therapeutic proteins into specific sites for the treatment of various diseases. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40260.

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Herein, a simple and effective method for the preparation of thiourea using a nucleophilic substitution reaction is reported. Urea and Lawesson’s reagent were used as the raw materials to prepare thiourea via a one-step method involving the sulfuration reaction, and the reaction mechanism was analyzed. The effect of the reaction time, reaction temperature, and mass ratio of the raw materials on the yield of thiourea were investigated.The most beneficial conditions used for the reaction were determined to be: Reaction time = 3.5 h, reaction temperature = 75°C, and mass ratio of urea to Lawesson’s reagent = 2:1. Under these optimal conditions, the average yield of thiourea over five replicate experiments was 62.37%. Characterization using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermogravimetric analysis (TGA) showed that the as-synthesized substance was thiourea. Our synthetic method has the advantages of high yield, mild reaction conditions and simplicity.

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