Dual-mode functionalization of CeO2 nanoparticles with thiolated dextran sulfate for enhanced colloidal stability and redox responsiveness

CeO₂ nanoparticles are promising materials for biomedical applications due to their unique surface properties and redox activity. However, achieving long-term colloidal stability and introducing stimulus-responsive functionalities remains a challenge. In this study, we developed a dual-functionalization strategy by chemically modifying dextran sulfate with thiol groups, allowing covalent attachment to CeO₂ surfaces while preserving electrostatic interactions. This approach combines electrostatic and steric stabilization, providing improved colloidal stability and enabling redox-responsive behavior through disulfide bond cleavage. A systematic comparative analysis was conducted to assess the effects of this strategy on hydrodynamic size, polydispersity, zeta potential, aggregation state, and colloidal stability, as well as the influence of pH and dispersion medium. The results identify the most effective functionalization method for controlled release and stimulus-responsive applications, offering new opportunities for the design of advanced nanoparticle systems.