Rapid and sensitive detection of rare cancer cells by the coupling of immunomagnetic nanoparticle separation with ELISA analysis

Hao-Yuan Cheng,¹ Lee-Jene Lai,² Fu-Hsiang Ko<sup>1

1</sup>Department of Materials Science and Engineering, National Chiao Tung University, Taiwan, Republic of China; ²National Synchrotron Radiation Research Center, Taiwan, Republic of China

Abstract: This study presents a rapid and sensitive method for detecting cancer cells occurring at low concentration. The method involves the simultaneous detection of two biomarkers of T helper cancer cells. One biomarker conjugates with immunofunctionalized magnetic nanoparticles (MNPs), enabling the separation of the T helper cells from a mixed population of cells. The other biomarker is used for detection during enzyme-linked immunosorbent assay (ELISA) analysis. The specific T helper cells can be quantified according to their ELISA absorbance values following magnetic separation. The experimental results demonstrate that immunofunctionalized MNPs can function as magnetic sensors and separate specific T helper cells from a mixed population with high efficiency and high specificity. Coupled with the ELISA technique, the immunofunctionalized MNPs can simultaneously detect rare cells. Results indicated increasing absorbance with increasing T cell number (from 10 to 10⁶). The total detection time was less than 15 minutes, even at a low T cell count. The advantages of the proposed method for detecting specific cells at low concentration include ease of preparation, low cost, rapid detection, and high sensitivity. The proposed system can be adopted to detect circulating tumor cells in early tumor stages for diagnostic or prognostic purposes.

Keywords: ELISA, magnetic nanoparticles, immunoassay, cancer cell

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