4 Conclusions
Since the discovery that an RNA molecule may have the capacity to
light up a fluorogen [7], many groups have started to develop
highly efficient, bright, photostable, and cell-permeable fluorogens
together with their specific aptamers. To this end, strong progresses
were made in the chemistry of the fluorogen but also in the development of new technologies and methodologies for highthroughput functional screening of mutant gene libraries as well
as for the stabilization of RNA probes both inside (e.g., Tornado
[68]) and outside (e.g., use of 2
0 -fluorinated ribose [133] and
L-enantiomers [78]) the cell.
While the main motivation in developing new efficient fluorogen/light-up aptamer pairs was mainly driven by the possibility of
imaging RNA in living cells with high sensitivity, one can see that
the application scope of these probes rapidly diversified toward the
sensitive sensing of a variety of molecules (DNA, protein, metabolites, and ions) both in live cells and in vitro. Indeed, the development and the commercialization of ultrasensitive detection kits may
have a profound impact on various fields such as healthcare and
environment survey. Light-up aptamers may also play a role in drug
discovery by allowing to set up high-throughput screening pipelines as well as by assisting the development of RNA nano-objects
that could act, for instance, as drug delivery cargos.
As a conclusion, it is likely that even more efficient fluorogen/
light-up aptamer pairs will be developed over the coming years and
that additional types of molecules beyond RNA will be used for the
development of light-up aptamers. Indeed, two DNA-based lightup aptamers have been described [12, 20] which may provide great
advantages in terms of cost and backbone stability. Moreover, one
can expect that the application spectrum of light-up aptamers will
continue to grow far beyond RNA detection and that first analysis
kits and devices using these molecules may appear on the market in
a near future. Therefore, the story of light-up aptamers is just
beginning.
References
1. Jin R, Breslauer KJ (1988) Characterization
of the minor groove environment in a drugDNA complex: bisbenzimide bound to the
poly[d(AT)].poly[d(AT)]duplex. Proc Natl
Acad Sci U S A 85(23):8939–8942
2. Armitage BA (2008) Cyanine dye–nucleic
acid interactions. In: Strekowski L
(ed) Heterocyclic polymethine dyes: synthesis, properties and applications. Springer, Berlin, pp 11–29. https://doi.org/10.1007/
7081_2007_109
3. Tyagi S (2009) Imaging intracellular RNA
distribution and dynamics in living cells. Nat
Methods 6(5):331–338. https://doi.org/10.
1038/nmeth.1321
4. Wang Z, Liu W, Fan C, Chen N (2019) Visualizing mRNA in live mammalian cells. Methods.
https://doi.org/10.1016/j.ymeth.
2019.03.008
5. Bertrand E, Chartrand P, Schaefer M, Shenoy
SM, Singer RH, Long RM (1998)
Light-Up RNA Aptamers
95
Since the discovery that an RNA molecule may have the capacity to
light up a fluorogen [7], many groups have started to develop
highly efficient, bright, photostable, and cell-permeable fluorogens
together with their specific aptamers. To this end, strong progresses
were made in the chemistry of the fluorogen but also in the development of new technologies and methodologies for highthroughput functional screening of mutant gene libraries as well
as for the stabilization of RNA probes both inside (e.g., Tornado
[68]) and outside (e.g., use of 2
0 -fluorinated ribose [133] and
L-enantiomers [78]) the cell.
While the main motivation in developing new efficient fluorogen/light-up aptamer pairs was mainly driven by the possibility of
imaging RNA in living cells with high sensitivity, one can see that
the application scope of these probes rapidly diversified toward the
sensitive sensing of a variety of molecules (DNA, protein, metabolites, and ions) both in live cells and in vitro. Indeed, the development and the commercialization of ultrasensitive detection kits may
have a profound impact on various fields such as healthcare and
environment survey. Light-up aptamers may also play a role in drug
discovery by allowing to set up high-throughput screening pipelines as well as by assisting the development of RNA nano-objects
that could act, for instance, as drug delivery cargos.
As a conclusion, it is likely that even more efficient fluorogen/
light-up aptamer pairs will be developed over the coming years and
that additional types of molecules beyond RNA will be used for the
development of light-up aptamers. Indeed, two DNA-based lightup aptamers have been described [12, 20] which may provide great
advantages in terms of cost and backbone stability. Moreover, one
can expect that the application spectrum of light-up aptamers will
continue to grow far beyond RNA detection and that first analysis
kits and devices using these molecules may appear on the market in
a near future. Therefore, the story of light-up aptamers is just
beginning.
References
1. Jin R, Breslauer KJ (1988) Characterization
of the minor groove environment in a drugDNA complex: bisbenzimide bound to the
poly[d(AT)].poly[d(AT)]duplex. Proc Natl
Acad Sci U S A 85(23):8939–8942
2. Armitage BA (2008) Cyanine dye–nucleic
acid interactions. In: Strekowski L
(ed) Heterocyclic polymethine dyes: synthesis, properties and applications. Springer, Berlin, pp 11–29. https://doi.org/10.1007/
7081_2007_109
3. Tyagi S (2009) Imaging intracellular RNA
distribution and dynamics in living cells. Nat
Methods 6(5):331–338. https://doi.org/10.
1038/nmeth.1321
4. Wang Z, Liu W, Fan C, Chen N (2019) Visualizing mRNA in live mammalian cells. Methods.
https://doi.org/10.1016/j.ymeth.
2019.03.008
5. Bertrand E, Chartrand P, Schaefer M, Shenoy
SM, Singer RH, Long RM (1998)
Light-Up RNA Aptamers
95