Sensitive single-color fluorescence "off-on" switch system for dsDNA detection based on quantum dots-ruthenium assembling dyads.
Due to the high importance of detecting DNA with both fast speed and high sensitivity, we proposed a new dsDNA detection method relying on a novel single-color fluorescence "off-on" switch system. Water-soluble glutathione capped CdTe QDs (emission at 605 nm) was prepared for taking advantage of the readily tunable emission property of QDs. Initially, QDs was completely quenched by the Ru(phen)2(dppz)(2+), as the spontaneous formation of QDs-Ru assembling dyads. Then, in the case of the addition of dsDNA, the Ru(phen)2(dppz)(2+) was removed away from the CdTe QDs, producing free CdTe QDs and the Ru-dsDNA complex. Both of them could be excited at the same wavelength and emit overlaid fluorescence. This single-color fluorescence "off-on" signal was sensitive to the concentration of dsDNA. Native dsDNA with the concentration of 10 pg/mL could be detected when 0.5 nM CdTe QDs was used, and ssDNA, RNA or BSA had no interference on it. With this system, the dsDNA samples of hepatitis B virus (HBV) patients were tested. The results were in good agreement with those detected by fluorescence quantitative PCR (P>0.05), and for those samples with very low DNA concentrations, this system could provide more accurate results, demonstrating the possible clinical applicability of this "off-on" switch system. For this system, chemical conjugation or labeling of probes is not required, and unmodified native DNA targets could be detected in less than half an hour. Therefore, a simple, fast, sensitive, low cost, highly selective and practically applicable detection system for dsDNA has been described.
School of Life Science, Beijing Institute of Technology, Beijing 100081, China.
Rui
R
Zhang
School of Life Science, Beijing Institute of Technology, Beijing 100081, China.
Dongxu
D
Zhao
Beijing YouAn Hospital, Capital Medical University, China.
Hui-Guo
HG
Ding
Beijing YouAn Hospital, Capital Medical University, China.
Yan-Xiang
YX
Huang
School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China.
Hai-Zheng
HZ
Zhong
School of Life Science, Beijing Institute of Technology, Beijing 100081, China. Electronic address: hyanxie@bit.edu.cn.
Hai-Yan
HY
Xie
D015374:Biosensing Techniques / Q000379:methods; D019187:Cadmium Compounds / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry; D004279:DNA, Viral / Q000032:analysis* / Q000235:genetics; D005456:Fluorescent Dyes / Q000737:chemistry*; D006509:Hepatitis B / Q000175:diagnosis*; D006515:Hepatitis B virus / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D045663:Quantum Dots / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods; D013691:Tellurium / Q000737:chemistry*
D019187:Cadmium Compounds; D056831:Coordination Complexes; D004279:DNA, Viral; D005456:Fluorescent Dyes; D012428:Ruthenium; D013691:Tellurium; C028337:cadmium telluride
Fluorescence; Off–on switch; Quantum dots; Single-color; dsDNA detection