Activatable fluorescence: From small molecule to nanoparticle.
Molecular imaging has emerged as an indispensable technology in the development and application of drug delivery systems. Targeted imaging agents report the presence of biomolecules, including therapeutic targets and disease biomarkers, while the biological behaviour of labelled delivery systems can be non-invasively assessed in real time. As an imaging modality, fluorescence offers additional signal specificity and dynamic information due to the inherent responsivity of fluorescence agents to interactions with other optical species and with their environment. Harnessing this responsivity is the basis of activatable fluorescence imaging, where interactions between an engineered fluorescence agent and its biological target induce a fluorogenic response. Small molecule activatable agents are frequently derivatives of common fluorophores designed to chemically react with their target. Macromolecular scale agents are useful for imaging proteins and nucleic acids, although their biological delivery can be difficult. Nanoscale activatable agents combine the responsivity of fluorophores with the unique optical and physical properties of nanomaterials. The molecular imaging application and overall complexity of biological target dictate the most advantageous fluorescence agent size scale and activation strategy.
Princess Margaret Cancer Centre and Techna Institute, University Health Network, Toronto, ON, Canada.
Benjamin M
BM
Luby
Princess Margaret Cancer Centre and Techna Institute, University Health Network, Toronto, ON, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada.
Danielle M
DM
Charron
Princess Margaret Cancer Centre and Techna Institute, University Health Network, Toronto, ON, Canada.
Christina M
CM
MacLaughlin
Princess Margaret Cancer Centre and Techna Institute, University Health Network, Toronto, ON, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada. Electronic address: gang.zheng@uhnres.utoronto.ca.
Gang
G
Zheng
D000818:Animals; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000032:analysis* / Q000737:chemistry*; D006801:Humans; D057054:Molecular Imaging; D053758:Nanoparticles / Q000032:analysis* / Q000737:chemistry*
D005456:Fluorescent Dyes
Aggregation; Beacon; Biosensing; Fluorophore; Molecular imaging; Nanocarrier; Smart probe; Theranostics