Abstract
Although cancer represents the leading cause of death worldwide, its burden could be largely reduced through implementation ofdiagnostic approaches for early detection and strategies to monitordisease progression and response to treatment. The development ofgenetically-encoded autofluorescent proteins, and the design of smallsynthetic probes with exceptional photophysical properties havecatalyzed the development of fluorescent biosensors that can reporton the relative abundance and dynamic behaviour of biomolecules.Together with these, major advances in high resolution imagingtechnologies have provided novel means to image biomolecules intheir natural environment in a sensitive yet non-invasive fashion.Molecular imaging with fluorescent biosensors allows the biologist tostudy dynamic processes in real time in healthy and pathological cellswith high spatial and temporal resolution. In addition, this technologyhas a number of practical applications in analytical chemistry andbiotechnology, and is widely applied to several areas of health and disease, including clinical diagnostics and preclinical evaluation ofcandidate drugs in drug discovery programmes. In particular moleculartracers, targeted probes and “smart probes” which are specificallyactivated by the tumour environment have been developed for imagingcancer and metastasis, and successfully applied to image-guidedsurgery. Fluorescent biosensors are expected to improve early cancerdetection, and to provide better means of determining cancer origin, stage and grade, thereby paving the way for personalized diagnosticsand theranostic applications. This chapter will focus on fluorescentbiosensor technology and molecular tracers for imaging biomarkers incancer and metastasis. Representative examples of molecular tracers, targeted probes and activatable sensors will be presented and futuredevelopments for diagnostic and imaging applications will be discussed, in particular strategies aimed at probing intracellular biomarkers thatcontribute to cancer cell proliferation, multiplexed sensing technologiesand potential theranostic applications.