Functional Magnetic Nanoparticles for Highly Efficient Cholesterol Removal

Abstract In this study, magnetic nanoparticles functionalized with carboxylated β‐cyclodextrin (CM‐β‐CD; referred to Fe 3 O 4 @CM‐β‐CD) were synthesized and used for the efficient removal of cholesterol from milk and egg yolk via host–guest interactions. The results of Fourier‐transform infrared, X‐ray photoelectron spectroscopy, and thermogravimetric analysis indicated that the CM‐β‐CD was successfully conjugated to the surface of Fe 3 O 4 , and the amount of CM‐β‐CD attached on Fe 3 O 4 @CM‐β‐CD was determined to be 9.164%. The X‐ray diffraction and transmission electron microscopy data revealed that the process of CM‐β‐CD coating did not result in a phase change of the Fe 3 O 4 , and the Fe 3 O 4 @CM‐β‐CD nanoparticles were determined to have an average size of about 15 nm. The results of isotherm adsorption and kinetic properties indicated that CM‐β‐CD functionalization increased the cholesterol removal efficiency, and the characteristics of cholesterol adsorption on Fe 3 O 4 @CM‐β‐CD were fitted well with the Langmuir adsorption model and Lagergren pseudo‐1st‐order kinetic models. Furthermore, compared with the Fe 3 O 4 nanoparticles, the functionalized Fe 3 O 4 @CM‐β‐CD nanoparticles exhibited greater cholesterol removal efficiency, and saponification of the milk and egg yolk was found to be beneficial for the cholesterol removal; using the Fe 3 O 4 @CM‐β‐CD nanoparticles, 98.8% and 94.6% of the cholesterol was extracted in 1 h from saponified milk and egg yolk, respectively, and the Fe 3 O 4 @CM‐β‐CD nanoparticles still displayed efficient cholesterol removal after 6 reuses.