With the development of proteome research,one of the most attractive contemporary endeavors is the pretreatment of peptides/proteins before separation and identification,particularly those with low level expression,such as secretome,serum peptides and so on.In this study,novel magnetic silica nanoparticle functionalized with layer-by-layer detonation nanodiamonds (dNDs) were prepared by coating single submicron-size magnetite particle with silica and subsequent modification with detonation nanodiamond by the diimide-activated amidation of detonation nanodiamond-bound carboxylic acids assisted by polyallylamine.With the characterization of vibrating-sample magnetometer,FT-IR,TEM and thermogravimetric analysis,the resulting layer-by-layer dNDs functionalized magnetic silica microspheres exhibited well-defined magnetite-core-silica-shell structure and possess high content of magnetite,which endow them with high dispersiblity and excellent magnetic responsibility.As a result of their excellent magnetic property,the synthesized dNDs-functionalized magnetic silica microspheres were successfully applied for convenient,fast and efficient pretreatment of low-abundance peptides/proteins from high-diluted sample solution.The signal intensity could be improved by at least two to three orders of magnitude.Even in high salt concentration solution,peptides/proteins could also be isolated effectively.The experiment results were almost the same with the results gained using dNDs,but shown more effectively efficiency with the magnetic core.The facile synthesis and the convenient and efficient enrichment process of the novel layer-by-layer dNDs-functionalize microspheres make it promising candidate for isolation of protein in secretome.