Magnetic Microspheres as Microrobot Bodies: Optimized Chitosan Modification and Gel Dispersion for Controlled Release of Doxorubicin

Although the loading and targeted release of drugs are core biomedical applications of micro-nano robots, they are restricted by the complexity of robot fabrication and drug loading/release regulation. This work adopts magnetic microspheres (MMs) as microrobot bodies, owing to their low driving resistance and ease of preparation, in order to explore the loading and release of anticancer drugs via physical adsorption and chitosan surface functionalization. Two modification routes, chitosan solution (CS) and chitosan colloid (CC), were compared in terms of their efficacy in fabricating magnetic chitosan microspheres (MCMs). The dispersion procedure of chitosan gel (CG)-encapsulated MMs was optimized to obtain microspheres with uniform size and good encapsulation. Doxorubicin (DOX) was used as a model drug, and the optimized microstructure exhibited high loading efficiency and excellent controlled release. This study offers a low-cost strategy to advance micro-nano robots toward targeted drug delivery applications.