Application of Semiconductor Quantum Dots for Breast Cancer Cell Sensing

Quantum dots (QDs) have received considerable attention due to their advantages that are suitable for biological studies, especially for multiplexed staining assays and immunological assays. Here we report an application of QDs for the detection of breast cancer cells. Breast cancer is the second most common type of cancer and the fifth most common cause of cancer deaths in the US and the world. The development of QD based sensing for breast cancer cells involved three kinds of antibodies, the first was for capture, the second was for labeling and the third was for imaging the breast cancer cells. The capture antibody, anti-Her2/neu, was covalently immobilized on silanized glass slide which was used to capture the SK-BR3 breast cancer cells. A second antibody, anti-EpCAM was then used for labeling the captured SK-BR3 cells. The third antibody against anti-EpCAM that was conjugated to QDs was used for imaging the captured cells. Images of SK-BR3 cells captured on the glass slide were evaluated under a UV source microscope. The preliminary studies showed that the imaging with QDs-antibody conjugates was successful. The QD breast cancer cell sensing had a brighter signal compared to the organic dye using similar parameters and the same number of cells. Future directions will involve elimination of non-specific signal as well as quantification to establish the limit of detection for the QD-based cell sensing.