Preparation and characterization of thermosensitive PNIPAA-coated iron oxidenanoparticles

Abstract

A new and facile approach was established to fabricate thermoresponsivepoly(N-isopropylacrylamide) (PNIPAA) coated iron oxide nanoparticles in a non-aqueous medium.The morphology and structure of the nanoparticle-doped composite were analyzed by meansof transmission electron microscopy (TEM), x-ray powder diffraction (XRD), andFourier transformation infrared spectrometry (FTIR). The thermosensitivity of thecomposite was also investigated. Results indicated that the oil-soluble iron oxidenanoparticles encapsulated with PNIPAA, composed of an inorganic iron oxidecore and biocompatible PNIPAA shell, were dispersed well in water and had asphere-like shape. The PNIPAA-coated iron oxide nanoparticles with such a kindof core–shell structure showed excellent thermosensitivity. Namely, the aqueoussuspension of PNIPAA-coated iron oxide nanoparticles dramatically changed fromtransparent to opaque as the temperature increased from room temperature to38 °C, showing potential as optical transmittance switch materials and their significance in thefields of protein adsorption and purification controlled release, and drug delivery.