Circulating tumor cell detection using magnetic nanosensor targeting epithelial–mesenchymal transition-specific markers

Circulating tumor cells (CTCs) are among the major causes of cancer metastasis, and their detection is critical in the context of early diagnosis and metastatic cancer marker. Despite various advances, well established approaches for CTCs are limited. This study aimed to develop a magnetic nanosensor-based approach for detecting CTCs across multiple cancers. Herein, iron oxide magnetic nanoparticles (MNP) were fabricated and coated with silica, characterized, and functionalized with antibody for epithelial cell adhesion molecule, an epithelial–mesenchymal transition marker. Additionally, the detection efficacy of the developed nanosensor was evaluated for HT-29 and MCF-7 cancer cell lines in vitro. Both base-MNPs (B-MNPs) and silica-coated MNPs (C-MNPs) showed notable characteristic peaks in ultraviolet-visible and Fourier-transform infrared spectra. Field-emission scanning electron microscopy showed the structural differences, with B-MNPs exhibiting a relatively uniform spherical distribution, whereas C-MNPs showed a markedly rough morphology. The results of zeta potential (−24 and −31 mV) and particle size analyses (78 and 112 nm) for B-MNPs and C-MNPs, respectively, indicated their physicochemical stability. Additionally, confocal laser scanning microscopy showed the successful antibody functionalization on the nanoparticle surface, and immunofluorescence images showed effective detection of both HT-29 and MCF-7 cells in vitro, with notable differences. Altogether, the findings of this study demonstrate that the proposed nanosensor could achieve effective detection of tumor cells regarding multi-cancer detection, providing a research basis for further development of an established protocol for circulating tumor cell detection.