Fabrication of ZMF@PS composite microspheres as T2 contrast agents with enhanced contrast performance and magnetic properties

The impacts of nanoplastics on the environment and organisms are gradually increasing, using MRI to detect the metabolic pathways of nanoplastics has low sensitivity and requires magnetic particles for enhanced visualization. In this study, we used Mn 0.6 Zn 0.4 Fe 2 O 4 nanoparticles as magnetic particles and coated them with polystyrene to afford polystyrene composite microspheres (ZMF@PS) with enhanced contrast performance. The effects of the polymerization parameters on the morphology and loading rate of the magnetic ZMF@PS composite microspheres were investigated. In addition, the effect of the magnetic contrast agent (ZMF particles) on the magnetic properties of the ZMF@PS composite microspheres was examined. The results show that when MAA and KPS quantities are 1 mL and 0.02 g, respectively, ZMF was uniformly distributed in the ZMF@PS composite microspheres exhibiting a good coating effect, with an average microsphere size of only 151.09 nm. Regarding the contrast performance, an increase in the ZMF content increased the loading rate, saturation magnetization intensity, and relaxation rate of the ZMF@PS composite microspheres. • Magnetic Mn 0.6 Zn 0.4 Fe 2 O 4 (ZMF) nanoparticles coated with polystyrene . • Homogenized ZMF@PS microspheres optimally synthesized with 1 mL of MAA and 0.02 g of KPS. • Methacrylic acid promoted the formation of core-shell structures. • ZMF@PS exhibit high magnetic properties at low ZMF loading rates. • ZMF@PS composite microspheres have reached a high level of contrast performance.