Abstract

Circulating tumor cell (CTC) is an evidenced biomarker for early cancer diagnosis and assessment of treatment response. This necessitates increasing attempt to develop new method for detection of CTCs with highly enriching and anti-interference capacity. Herein, we built a simple platform for CTC detection by combining aptamer-mediated specific recognition with affinity magnetic levitation (Maglev). The method involved modification of DNA tetrahedron (TDN) using SYL3C aptamer as tentacles, assembly of aptamer conjugated-TDN on microsphere by azide-alkyne click chemistry, enrichment of CTCs by the activated microspheres, and detection of CTCs by affinity Maglev. These yielded an aptamer sensor resembling octopus tentacles to enhance the capture selectivity and efficiency of CTCs. Once CTCs were captured, a microsphere@TDN@CTCs complex was formed, resulting in a change in the overall density. The number of CTCs was calculated by measuring the levitation height difference between microspheres pro- and post-binding of CTCs in affinity Maglev. An example study on MCF-7 cells exhibited a detection of 8.81 cells mL −1 in buffer solution, with repeatability characterized by a relative standard deviation of less than 4.48%, in comparison to 9.08 cell mL −1 in mimic clinical sample with a relative standard deviation of 6.98%. Analysis of mimic clinical samples demonstrated that the method was effective for the specific detection of CTCs with robust resistance to interference from co-existing substances in plasma. It is possible to serve as an early diagnostic alternative for clinically relevant cancers once large number of clinical trials are performed.