Molecularly imprinted hollow sphere array for the sensing of proteins.

Mono-dispersed molecularly imprinted hollow spheres (MIHSs) for hemoglobin (Hb) were prepared by employing silica nanospheres as the sacrificial templates. The obtained hollow spheres with uniform particle size of 360 nm in diameter were characterized by transmission electron microscopy. The outstanding affinities of these MIHSs to the target protein were confirmed by adsorption experiment in aqueous solution. Adsorption equilibrium was achieved within 10 min while the binding capacity (Qmax ) of Hb was 8.84 µmol g(-1) at pH7.0. Furthermore, the MIHSs were successfully assembled into a closely-packed 3D colloidal array. The molecularly imprinted hollow sphere array (MIHSA) can selectively recognize Hb. As the concentration of Hb increased, the structure color of the MIHSA changed from blue to green, and turn to white finally with maximum red shift for 43 nm. The MIHSA showed promising potential for the naked-eye detection of target Hb. Reflection spectra of the MIHSA in response to different Hb concentrations (0.075-15 µmol L(-1) ).