Single-molecule DNA biosensors for quantitative transcription factor detection

We have developed two single-molecule fluorescence biosensors that can quantitatively detect single or multiple transcription factors (TFs) with high sensitivity and specificity. The first sensor is based on TF-based coincidence of two DNA fragments, each containing half of a particular TF binding sequence. In the absence of the particular transcription factor, the DNA fragments diffuse independently. The coincidence is detectable using 2-colour alternating laser excitation (ALEX) spectroscopy using either solution or surface-based approaches