This review examines metal enhanced fluorescence (MEF) using gold (Au) nanostructures, with a focus on biomedical applications of this phenomenon, namely fluorescence biosensing and imaging. The mechanism by which MEF occurs will be briefly discussed before a thorough review of recent investigations, particularly surrounding cancer detection and imaging. Work in this field has primarily focused on substrate-based MEF and more recently has explored solution-based enhancement. Therefore, this review will examine both the different nanostructured substrates as well as the colloidal nanomaterials that have been synthesized, along with their interactions with fluorescent molecules. The potential applications of plasmonic probes for optical imaging, particularly in the near-infrared II (NIR-II) window, are also discussed. By incorporating MEF into diagnostic and imaging techniques, it is expected that there will be dramatic improvements to patient survival rates via early diagnosis and efficient treatment.
