Rapid and sensitive detection of cancer cells by coupling with quantum dots and immunomagnetic separation at low concentrations

This work presents a rapid and sensitive method for detecting cancer cells at low concentration. In this method, two biomarkers of T-help cancer cells are detected simultaneously. One biomarker is conjugated with magnetic beads to separate T-help cell from the mixed cells and the other biomarker, associated with quantum dots, is used to detect fluorescence. The specific T-help cells can be quantified using the relationship between the QD fluorescence intensity and the cell frequency following magnetic separation. The intensity of fluorescence increases linearly with the frequency of T-help cells from 10−7 to 10−3, and neither B cells nor red blood cells interfere with the detection of T-help cells. Moreover, the total detection time is under 15 min, even though the frequency of specific T-help cells is as low as 5 × 10−7. The numerous advantages of detecting specific cells at low concentration using the presented method include ease of preparation, low cost, fast detection, and high sensitivity.