Surface modification of Nd3+ activated gadolinium core-shell nanospheres for near-infrared and magnetic resonance dual functional bioimaging system

•Gadolinium-based hydroxides Gd(CO3)OH with core–shell nanosphere morphology was synthesized. Through a series of surface modification, the particle shape, size and shell thickness could be continuously tuned, which affected both the near infrared and magnetic resonance imaging properties.•Rare earth Nd3+ was doped into Gd(CO3)OH and its near infrared luminescent properties were studied for the first time, which showed strong luminescence penetrating biological tissue under 808 nm laser excitation and could be effectively used in optical imaging.•The final core–shell nanospheres exhibited better magnetic resonance contrast enhancement than clinical contrast agent, and performed distinct imaging effect in vivo, which indicates the great potential as near infrared and magnetic resonance dual functional bioimaging system.