Enterovirus 71 adsorption on metal ion-composite chitosan beads

In this study, we developed composite chitosan beads combining various metal ions, including Ni(2+), Cu(2+), Zn(2+), and Fe(2+), for direct adsorption of enterovirus 71 (EV71). The metal-ion species had significant effects on the adsorption capacity of beads. Among these metal ion-composite chitosan beads, Ni(2+)-chitosan beads exhibited the best adsorption capacity of EV71. Using a concentration of 0.01-M Ni(2+) was found to best provide for bead formation and EV71 adsorption. The adsorption of EV71 for Ni(2+)-chitosan beads at neutral or alkaline pH was favored. Under a competitive condition with albumin proteins, Ni(2+)-chitosan beads exhibited significant capacity of EV71 adsorption in culture media. The adsorption of EV71 on the Ni(2+)-chitosan beads was attributed to the strong binding between Ni(2+) ions chelated to the surface amino acid of EV71 capsids and Ni(2+) ions chelated on the chitosan materials. Moreover, the adsorbed EV71 retained its antigenicity and infectivity after desorption. The Ni(2+)-chitosan beads exhibit a promising application to EV71 adsorption and removal.