Top Med Chem (2020) 34: 149–184
DOI: 10.1007/7355_2019_90
© Springer Nature Switzerland AG 2019
Published online: 11 March 2020
Applications of Fluorescent Protein-Based
Sensors in Bioimaging
Uday Kumar Sukumar, Arutselvan Natarajan, Tarik F. Massoud,
and Ramasamy Paulmurugan
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
2 Fluorescent Biosensors and Evolution of Fluorescent Protein Palette . . . . . . . . . . . . . . . . . . . . . 150
3 Genetically Encoded Sensors (GES) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
3.1 Intrinsic Environment-Sensitive Fluorescent Protein Biosensor (Single FP-Based
Sensors) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
3.2 Fluorescent Protein Complementation (Split Fluorescent Proteins) Sensors . . . . . . . . . 160
3.3 FRET Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
3.4 Translocation Sensors/Assays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
4 Advances in Biosensors for Animal Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
5 Drawbacks Associated with the Use of Fluorescent Proteins in Biosensors . . . . . . . . . . . . . . . 174
6 Conclusion and Future Perspectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
Abstract In the last two decades, there have been enormous developments in the
area of reporter gene imaging for various bioimaging applications, especially to track
cellular events that are occurring in intact cells and cells within living animals. As
part of this process, there has been a significant interest in identifying new reporters
or developing new substrates that can allow us to image multiple cellular events
simultaneously without any signal overlap between the targets. Even though chemical dyes are useful for some of these applications, reporter proteins which mimic
biological properties of proteins when tagged directly with the target proteins are
very useful. Although molecular imaging has significantly advanced through use of
different imaging probes (radiolabeled ligands, MR contrast agents, CT contrast
agents, fluorescent dyes, fluorescent and bioluminescent proteins) and techniques
(PET, SPECT, MRI, CT, optical, ultrasound, and photoacoustic imaging), optical
imaging, such as fluorescence and bioluminescence imaging, has shown promising
applications in various preclinical settings, especially in imaging cellular pathways
and studies involving drug development. This is mainly owing to its simple and easy
U. K. Sukumar, A. Natarajan, T. F. Massoud, and R. Paulmurugan (*)
Molecular Imaging Program at Stanford, Department of Radiology, Stanford University School
of Medicine, Stanford, CA, USA
e-mail: paulmur8@stanford.edu
DOI: 10.1007/7355_2019_90
© Springer Nature Switzerland AG 2019
Published online: 11 March 2020
Applications of Fluorescent Protein-Based
Sensors in Bioimaging
Uday Kumar Sukumar, Arutselvan Natarajan, Tarik F. Massoud,
and Ramasamy Paulmurugan
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
2 Fluorescent Biosensors and Evolution of Fluorescent Protein Palette . . . . . . . . . . . . . . . . . . . . . 150
3 Genetically Encoded Sensors (GES) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
3.1 Intrinsic Environment-Sensitive Fluorescent Protein Biosensor (Single FP-Based
Sensors) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
3.2 Fluorescent Protein Complementation (Split Fluorescent Proteins) Sensors . . . . . . . . . 160
3.3 FRET Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
3.4 Translocation Sensors/Assays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
4 Advances in Biosensors for Animal Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
5 Drawbacks Associated with the Use of Fluorescent Proteins in Biosensors . . . . . . . . . . . . . . . 174
6 Conclusion and Future Perspectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
Abstract In the last two decades, there have been enormous developments in the
area of reporter gene imaging for various bioimaging applications, especially to track
cellular events that are occurring in intact cells and cells within living animals. As
part of this process, there has been a significant interest in identifying new reporters
or developing new substrates that can allow us to image multiple cellular events
simultaneously without any signal overlap between the targets. Even though chemical dyes are useful for some of these applications, reporter proteins which mimic
biological properties of proteins when tagged directly with the target proteins are
very useful. Although molecular imaging has significantly advanced through use of
different imaging probes (radiolabeled ligands, MR contrast agents, CT contrast
agents, fluorescent dyes, fluorescent and bioluminescent proteins) and techniques
(PET, SPECT, MRI, CT, optical, ultrasound, and photoacoustic imaging), optical
imaging, such as fluorescence and bioluminescence imaging, has shown promising
applications in various preclinical settings, especially in imaging cellular pathways
and studies involving drug development. This is mainly owing to its simple and easy
U. K. Sukumar, A. Natarajan, T. F. Massoud, and R. Paulmurugan (*)
Molecular Imaging Program at Stanford, Department of Radiology, Stanford University School
of Medicine, Stanford, CA, USA
e-mail: paulmur8@stanford.edu