β-Cyclodextrin coated and folic acid conjugated magnetic halloysite nanotubes for targeting and isolating of cancer cells.

The study developed a simple, effective and inexpensive strategy for capturing, enriching and detecting circulating tumor cells (CTCs) by using folic acid (FA) as the targeting molecule instead of antibodies. This work constructed magnetic halloysite nanotubes (MHNTs) coated with biocompatible β-cyclodextrin (CD), and conjugated to FA via a PEG-Ad linker, to specifically capture the FA receptor (FR)-overexpressing cancer cells. The capture efficiencies of MHNTs@β-CD@Ad-PEG-FA for the Skov3, Hela and A549 cancer cells were 96.3%, 97.0% and 95.6% respectively. In addition, the nanoparticles were able to capture very low numbers of the cancer cells (25-500 cells/mL) from PBS and whole blood, as well as selectively capture the cancer cells over normal HEK 293 T cells. Furthermore, the captured cells were viable and grew normally in vitro, indicating the future potential of downstream analyses. This approach can be adapted for different CTCs, once the tumor-specific surface markers are identified and the efficacy of targeting ligands is established. Taken together, FA-conjugated MHNTs nanoparticles are a highly promising tool for isolating CTCs for the diagnosis and treatment of cancer.