Circulating tumor cells (CTCs) have great significance in cancer diagnosis, therapy and metastasis prevention, owing to their biological characteristics derived from themselves and primary tumor. However, low concentrations of CTCs in peripheral blood made their detection, isolation and enrichment technically challenging. In this study, we selected colon cancer HT29 cell as a CTC model and took the nanoscale G6 PAMAM dendrimers as scaffolds for multivalent conjugation with antibody against EpCAM to realize the specific capture and activity regulation at HT29 cells in vitro. FTIR, DLS, UV and fluorescence measurements were made to show the physicochemical properties of conjugates. Microscopic analysis was performed to indicate the recognition and capture behaviors to target cells. MTT, fluorescence and flow cytometric analyses were made to demonstrate the regulation on the viability of captured cells. Our results showed that the prepared conjugates were able to specifically recognize and bind the adherent and floating HT29 cells, and down-regulate the activity of captured cells without producing significant cytotoxic effects. The present study may provide promise for capturing and restraining the rare CTCs in patient blood by using nanomaterials multivalently conjugated with targeting antibodies against biomarkers on CTC surface.

circulating tumor cells  /  PAMAM dendrimers  /  antibody conjugation  /  cell capture  /  cell activity regulation