Self-assembled supramolecular immunomagnetic nanoparticles through π-π stacking strategy for the enrichment of circulating tumor cells

Owing to their high-specific binding toward targets as well as fast and convenient separation operations, immunomagnetic beads (IMBs) are widely used in the capture and detection of circulating tumor cells (CTCs). To construct the IMBs, surface modifications are generally performed to functionalize the magnetic cores (e.g. Fe3O4 nanoparticles), and the employed surface modification strategies normally influence the structure and functions of the prepared IMBs in return. Different from the existing work, we proposed the use of supramolecular layer-by-layer (LBL) self-assembly strategy to construct the IMBs. In general, owing to the pi-pi stacking interactions, the polydopamine, graphene oxide and 'molecular glue' gamma-oxo-1-pyrenebutyric acid were self-assembled on Fe3O4 nanoparticles sequentially, thereby accomplishing the integration of different functional components onto magnetic cores to prepare the self-assembled supramolecular immunomagnetic beads (ASIMBs). The ASIMBs showed high sensitivity, specificity and good biocompatibility to the model CTCs and low nonspecific adsorption to the negative cells (similar to 93% for MCF-7 cells and 17% for Jurkat cells). Meanwhile, ASIMBs possessed a remarkable potential to screen the rare MCF-7 cells out of large amounts of interfering Jurkat cells with the capture efficiency of 75-100% or out of mouse whole blood with the capture efficiency of 20-90%. The captured cells can be further recultured directly without any more treatment, which showed huge applicability of the ASIMBs for in vitro detection in clinical practices.

Automated summary

Due to their high-specific binding toward targets and fast and convenient separation operations, immunomagnetic beads (IMBs) are widely used in the capture and detection of circulating tumor cells (CTCs). In this study, a supramolecular layer-by-layer (LBL) self-assembly strategy was proposed to construct the IMBs, which showed high sensitivity, specificity and good biocompatibility for capturing and detecting CTCs. The captured cells can be further recultured directly, demonstrating the huge potential of the IMBs for in vitro detection in clinical practices.