Electrochemical sensing of target cells based on a peptide/single-strand DNA probe

To electrochemically measure human myeloid leukemia cells (K562 cells), we constructed a probe consisting of peptide/single-strand (ss) DNA. Ac-H₆Y₄C with an acetylated N-terminal of peptide was used to enhance the probe to allow electrode responses that could detect target cells. A ss-DNA was selected as the target cell recognition moiety. The probe exhibits properties that combine the functionalities of both DNA and peptides. The measurement principle is based on changes in the peak currents of the peptide moieties that are caused by interactions between the ss-DNA and target cells. The peak currents were proportional to the concentration of K 562 cells that ranged from 10 to 2,000 cells/mL with a LOD of 3 cells/mL.