Immunomagnetic particles exhibiting programmable hierarchical flower-like nanostructures for enhanced separation of tumor cells†

Immunomagnetic particles are extensively used for the separation of biological molecules and particles, and have exhibited great potential in many fields including biosensors, disease diagnosis and biomedical engineering. However, most immunomagnetic particles exhibit a smooth surface, resulting in a limited separation efficiency for biological particles featuring enormous surface nanostructures, such as tumor cells. Here we report flower-like immunomagnetic particles (FIMPs) prepared by streptavidin (SA)-assisted biomineralization and one-step antibody modification, and demonstrate their superior capability for highly efficient and selective separation of circulating tumor cells (CTCs). SA can link inorganic nanosheets and magnetic nanoparticles together to obtain FIMPs with programmable hierarchical flower-like nanostructures and provide enormous binding sites for post-antibody modification. The synergetic effect of nano-sized petals and micro-sized particles in the hierarchical nanostructure enhances the interaction between the cells and the matrix, thus enabling FIMPs to separate CTCs with high selectivity and high efficiency. Our study provides a promising platform for the selective separation of trace biological molecules and particles from complex samples and shows great potential for downstream detection and diagnosis.