Bioconjugated Janus Particles Prepared by in Situ Click Chemistry

Janus silica particles decorated with biotin molecules and poly(ethylene oxide) PEO chains on two hemispheres were prepared by two-step click reactions. Polystyrene (PS) particles coated with azide modified silica particles were used as templates. On the PS surface one hemisphere of a silica particle was exposed to the solvent and the other one was embedded in PS. The alkynated biotin molecules were grafted onto the exposed side of the silica particle by click reaction. After removal of PS, the embedded part of the silica particle was released, and alkynated PEO chains were grafted to the particle by click reaction. FT-IR, TGA, and TEM were employed to characterize the Janus particles. The Janus particles show strong interaction with avidin.