DNA‐Templated Magnetic Nanoparticle‐Quantum Dot Polymers for Ultrasensitive Capture and Detection of Circulating Tumor Cells

Circulating tumor cell (CTC) enumeration and analysis has emerged as an important platform for cancer diagnosis and prognosis. A great challenge, however, is to efficiently capture low abundant CTCs with high purity from blood samples in a rapid and high‐throughput manner for accurate and sensitive CTC detection. Herein, a new class of DNA‐templated magnetic nanoparticle‐quantum dot (QD)‐aptamer copolymers (MQAPs) is developed for rapid magnetic isolation of CTCs from human blood with high capture efficiency and purity approaching 80%. The phenotype of CTCs is simultaneously profiled with QD photoluminescence (PL) at single cell level. These MQAPs are constructed through hybridization chain reaction to achieve amplified magnetic response, extraordinary binding selectivity for target cells over background cells, and ultra bright ensemble QD PL for single cell detection. MQAPs are free from nonspecific binding that would otherwise compromise the capture purity of target cells. As a result, facile isolation and enumeration of rare CTCs in blood samples could be achieved in 20 min with high sensitivity and accuracy.