Integrated high-efficiency protein adsorption-magnetic separation: preparation and performance optimization of thiolated magnetic cellulose microspheres

Thiol/MCMs-Ni microspheres synthesized via green aqueous epoxy-thiol grafting. • Microspheres are uniform 2 μm spheres with superparamagnetism, enabling rapid magnetic separation within 30 s. • Achieves high BSA adsorption capacity of 77.37 mg/g, fitting Langmuir isotherm and pseudo-second-order kinetics. • More than 91.5% elution efficiency and 67.56 mg/g capacity after five cycles, demonstrating excellent recyclability. In this study, cellulose was epoxy-functionalized with glycidyl methacrylate (GMA), and sodium hydrosulfide (NaHS) was further introduced to successfully prepare thiol-modified magnetic cellulose microspheres (Thiol/MCMs-Ni) for protein separation research. This green and scalable strategy addresses the pressing demand for efficient adsorbents in downstream bioprocessing, where rapid magnetic separation can circumvent conventional centrifugation and filtration bottlenecks, reducing operational complexity and cost. The material was systematically characterized by FTIR, XRD, SEM, VSM, and XPS. The results indicated that the Thiol/MCMs-Ni microspheres exhibited a regular spherical shape with a particle size of approximately 2 μm, while also demonstrating good magnetic responsiveness and thermal stability. Adsorption experiments using bovine serum albumin (BSA) as a model protein showed that the adsorption behavior conformed to the pseudo-second-order kinetic model and the Langmuir isotherm adsorption model, with a maximum adsorption capacity of 77.37 mg/g. Thermodynamic analysis indicates that the adsorption is a spontaneous and endothermic process, and the material still maintains a high elution efficiency of more than 91.5% after five cycles of use. This study provides a novel approach for developing efficient and green materials for protein separation. Download: Download high-res image (140KB) Download: Download full-size image