Multifunctional Magnetic Cellulose Surface-Imprinted Microspheres for Highly Selective Adsorption of Artesunate

Molecularly imprinted magnetic cellulose microspheres (MIP-MCM) of artesunate (Ars) are developed by a surface functional monomer-directing system. MIP-MCM are obtained by coating a layer of MIP on the surface of the cellulose and Fe₃O₄ composite microspheres. The composite materials are characterized by Fourier transform infrared spectra (FTIR), X-ray powder diffraction (XRD), vibrating sample magnetometry (VSM), UV-vis spectrophotometry (UV), dynamic light scattering (DLS), and magnetic resonance imaging (MRI). They are adsorption-selective to Ars, highly regenerate, and stable in wide pH and temperature ranges. The adsorption of Ars reaches equilibrium within 10 h, and the maximum adsorption quantity is as high as 0.22 mg/mg, much better than previous reports. Through the Langmuir-Freundlich isotherm and pseudo-second-order kinetic model, the adsorption kinetics and thermodynamics of MIP-MCM were studied. The thermodynamic studies suggest that the adsorption of Ars on MIP-MCM is a spontaneous process. MIP-MCM also show rapid magnetic separation and high reusability (retained 90% after five cycles). Thus, it is an efficient method for Ars separation and purification. Furthermore, MIP-MCM are good negative MRI contrast agents with good biocompatibility. Due to these properties, this work offers a new potential application for MIP-MCM in aspects of drug delivery and tracking, disease diagnosis, and therapy.