Development and optimisation of responsive photoacoustic contrast agents for early detection of cancer

Photoacoustic imaging (PAI) is a promising (pre)clinical imaging modality that detects acoustic signals generated by absorption of short laser pulses. The technique combines the high contrast of optical techniques, due to different absorption spectra of tissue and contrast agents (CAs), with the improved penetration depth (up to 5 cm) of acoustic methods, as acoustic waves scatter less than photons, making it ideal for deep, high-resolution 3D imaging. CAs can further enhance signal in specific regions or report on disease states for diagnosis.
Within the Early Diagnosis of Priority Diseases theme, PAI CAs based on responsive near-infrared-absorbing will be developed for functional photoacoustic imaging. For example, a dye responsive to the nitroreductase enzyme that is upregulated in hypoxic tumours. Optimised CAs will be evaluated in cancer cell lines and 3D spheroids (breast/prostate models available) and phantom materials using NPL's PA microscope and in-development PAI tomography system. We will establish robust protocols that ensure optimum transmission and detection to maximise the response of the CAs. Close collaboration on development of hardware at NPL, CAs at Strathclyde, and drug-development applications at GSK will mean the PAI methods and tools delivered meet stakeholder needs.