A transistor-like pH nanoprobe for tumour detection and image-guided surgery

It is challenging to detect a broad range of malignant tumours at high resolution, because of profound genetic and histological differences in cancerous tissue. Here, we report the design and performance of a fluorescent nanoprobe with transistor-like responses (transition pH = 6.9) for the detection of deregulated pH, which drives many of the invasive properties of cancer. The nanoprobe amplifies the fluorescence signal in the tumour over that in the surrounding normal tissues, resulting in a discretized, binary output signal with a spatial resolution smaller than 1 mm. The nanoprobe allowed us to image a broad range of tumours in mouse models using a variety of clinical cameras. We were able to perform real-time tumour-acidosis-guided detection and surgery of occult nodules (<1 mm3) in mice bearing head and neck or breast tumours, significantly lengthening mice survivability. We also show that the pH nanoprobe can be used as a reporter in a fast, quantitative assay to screen for tumour-acidosis inhibitors. The binary delineation of pH achieved by the nanoprobe promises to improve the accuracy of cancer detection, surveillance and therapy. A fluorescent nanoprobe that amplifies the fluorescent signal in a broad range of tumours allows for real-time tumour-acidosis-guided detection and surgery of occult, less-than-1-mm3 nodules in mice bearing head and neck or breast tumours.