Time-resolved probes based on guanine/thymine-rich DNA-sensitized luminescence of terbium(III).
In this study, we have developed a novel strategy to highly sensitize the luminescence of terbium(III) (Tb(3+)) using a designed guanine/thymine-rich DNA (5'-[G3T]5-3') as an antenna ligand, in which [G3T]5 improved the luminescence of Tb(3+) by 3 orders of magnitude due to energy transfer from nucleic acids to Tb(3+) (i.e., antenna effect). Furthermore, label-free probes for the luminescent detection of biothiols, Ag(+), and sequence-specific DNA in an inexpensive, simple, and mix-and-read format are presented based on the [G3T]5-sensitized luminescence of Tb(3+) (GTSLT). The long luminescence lifetime of the probes readily enables time-resolved luminescence (TRL) experiments. Hg(2+) can efficiently quench the luminescence of Tb(3+) sensitized by [G3T]5 (Tb(3+)/[G3T]5); however, biothiols are readily applicable to selectively grab Hg(2+) for restoration of the luminescence of Tb(3+)/[G3T]5 initially quenched by Hg(2+), which can be used for "turn on" detection of biothiols. With the use of cytosine (C)-rich oligonucleotide c[G3T]5 complementary to [G3T]5, the formed [G3T]5/c[G3T]5 duplex cannot sensitize the luminescence of Tb(3+). However, in the presence of Ag(+), Ag(+) can combine the C base of c[G3T]5 to form C-Ag(+)-C complexes, leading to the split of the [G3T]5/c[G3T]5 duplex and then release of [G3T]5. The released [G3T]5 acts as an antenna ligand for sensitizing the luminescence of Tb(3+). Therefore, the Tb(3+)/[G3T]5/c[G3T]5 probe can be applied to detect Ag(+) in a "turn on" format. Moreover, recognition of target DNA via hybridization to a molecular beacon (MB)-like probe (MB-[G3T]5) can unfold the MB-[G3T]5 to release the [G3T]5 for sensitizing the luminescence of Tb(3+), producing a detectable signal directly proportional to the amount of target DNA of interest. This allows the development of a fascinating label-free MB probe for DNA sensing based on the luminescence of Tb(3+). Results and methods reported here suggest that a guanine/thymine-rich DNA-sensitized luminescence probe of Tb(3+) represents a new opportunity for versatile background-free biosensing applications.
Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science & Technology , Meilong Road 130, Shanghai, 200237, China.
Min
M
Zhang
Huynh-Nhu
HN
Le
Xiao-Qin
XQ
Jiang
Bin-Cheng
BC
Yin
Bang-Ce
BC
Ye
D004247:DNA / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry*; D006801:Humans; D049408:Luminescent Agents / Q000737:chemistry*; D008163:Luminescent Measurements / Q000379:methods*; D013725:Terbium / Q000737:chemistry*; D013941:Thymine / Q000737:chemistry*; D013997:Time Factors
D049408:Luminescent Agents; D013725:Terbium; D006147:Guanine; D004247:DNA; D013941:Thymine