Magnetic nanoparticles (MNPs) covalently coated by PEO–PPO–PEO block copolymer for drug delivery

A stable drug carrier has been prepared by covalently coating magnetic nanoparticles (MNPs) with PEO–PPO–PEO block copolymer Pluronic P85. The particles were characterized by TEM, XRD, DLS, VSM, FTIR, and TGA. A typical product has a 15 nm magnetite core and a 100 nm hydrodynamic diameter with a narrow size distribution and is superparamagnetic with large saturation magnetization (57.102 emu/g) at room temperature. The covalently-coated Pluronic-MNPs (MagPluronics) were proven to be stable in different conditions, such as aqueous solution, 0.2 M PBS solution, and pH 13.5 solution, which would be significant for biological applications. Furthermore, MagPluronics also possess temperature-responsive property acquired from the Pluronic copolymer layer on their surface, which can cause conformational change of Pluronics and improve load and delivery efficiency of the particles. The temperature-controlled loading and releasing of hydrophobic model drug curcumin were tested with these particles. A loading efficiency of 81.3% and a sustained release of more than 4 days were achieved in simulated human body condition. It indicates that the covalently-coated MagPluronics are stable carriers with good drug-loading capacity and controlled-release property.

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► The magnetic nanoparticles are covalently coated by Pluronic P85 as drug carriers.
► The synthesis route of the drug carriers is easy and green.
► The drug carriers are superparamagnetic, water-disperse, and temperature-responsive.
► The drug carriers greatly improve the solubility and bioavailability of curcumin.
► The drug carriers are more stable, biocompatible, and suitable for drug delivery.