Fluorescent recognition of deoxyribonucleic acids by a quantum dot/meso-tetrakis(N-methylpyridinium-4-yl)porphyrin complex based on a photo induced electron-transfer mechanism.
We have developed a new fluorescent probe of thioglycolic acid (TGA)-capped CdTe quantum dots (QDs) complexed with a model drug, meso-tetrakis(N-methylpyridinium-4-yl)porphyrin (TMPyP) for detecting deoxyribonucleic acids (DNAs). This probe operates with an "Off-On" mode: TMPyP quenches the photoluminescence (PL) of QDs via a photo induced electron-transfer (PIET) process; the presence of DNA can break the QD/TMPyP complexation, interrupting the PIET process, and switch on the PL of QDs. Sensitive detection of DNA with the detection limit of 0.16 nM and a linear detection range of 0.25-6.0 nM are achieved. Importantly, this probe can be used to distinguish the binding modes of DNA-TMPyP interactions, exhibiting the DNA sequence-dependent PL recovery behaviors. The obtained binding constant for poly(dA)·poly(dT) is ∼3.30×10(7) L mol(-1), which is approximately one order of magnitude larger than those for native DNAs and poly(dG)·poly(dC). Furthermore, the thymine bases preferential of the TMPyP-DNA interaction is proved by this probe.
State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, China.
Kao
K
Zhu
State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, China.
Xianyun
X
Hu
Research Center for Learning Science, Southeast University, Nanjing 210096, China.
Qinyu
Q
Ge
State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, China. Electronic address: sunqj@seu.edu.cn.
Qingjiang
Q
Sun
D004247:DNA / Q000737:chemistry*; D004579:Electron Transport; D005456:Fluorescent Dyes / Q000737:chemistry*; D008027:Light; D057230:Limit of Detection; D011166:Porphyrins / Q000737:chemistry*
D005456:Fluorescent Dyes; D011166:Porphyrins; C540459:meso-tetrakis(N-methylpyridinium-4-yl)porphyrin; D004247:DNA
Electrostatic assembly; Fluorescent probe; Nucleic acids; Porphyrin; Quantum dot