Conjugation of catecholamines on magnetic nanoparticles coated with sulfonated chitosan

We synthesized a novel magnetic nanoparticle coated with sulfonated complex (HSO3-CS-DMSA) of meso-2, 3-dimercaptosuccinic acid (DMSA) and chitosan (CS) to improve conjugation of catecholamines (CAs) on nanoparticles. HSO3-CS-DMSA@MNPs exhibited the highest CAs’ conjugation efficiency among three types of magnetic nanoparticles. CAs’ conjugation efficiency was increased in order of MNPs, DMSA@MNPs and HSO3-CS-DMSA@MNPs. CAs’ conjugation efficiency at pH 7 depended on zeta potential of magnetic nanoparticles and catecholamines were partly desorbed after being washed with acidic solutions. These results showed that the electrostatic interaction between the negatively charged nanoparticles and positively charged amino groups of catecholamines might play an important role in CAs’ conjugation on magnetic nanoparticles.