Dec6, 2012

Xuyin Zhao

Journal Report DNA模板引导 Ag纳米探针的合成

A new molecular probe for homogeneous detection of

nucleic acid targets

HSIN-CHIH YEH, JASWINDER SHARMA, JASON J. HAN, JENNIFER

S. MARTINEZ, AND JAMES H. WERNER

IEEE NANOTECHNOLOGY MAGAZINE ,2011,28-33

FIGURE 1 (a) Schematic and data showing the red fluorescence enhancement of DNA/Ag NCs caused by guanine proximity. The excitation and emission peaks of the light-up NCs are at 580 nm and 636 nm, respectively. (b) NCB (consisting of an NC probe and a G-rich probe) detection scheme. NCBs light up in the presence of a DNA target. In the absence of target, NCBs remain dark.

FIGURE 2 Dark DNA/Ag NCs templated on the NC-nucleation sequence 5’-C3TTAATC4 can be lit up into three distinct colors by bringing different DNAsequences (proximal sequences) into their proximity. (a) Photograph of the four samples under UV (365 nm) irradiation. The proximal sequences used are as follows: none (S0), 3’-T12 (S1), 3’-(G4A)3G3 (S2), and 3’-(G4T)3G3 (S3), respectively. (b) Normalized excitation/emission spectra of S1, S2, and S3 samples. Dashed lines represent the excitation spectra and the solid lines represent the emission spectra. Normalization scale is set differently to ease visualization.

FIGURE 3 (a) Photograph of the six pairs of samples under UV (365 nm) irradiation. In each pair of samples, the sample on the left contains one of the six NC-bearing strands (with Ag NCs on them). The sample on the right contains both the NC-bearing strand and a common G-rich strand [having proximal sequence of 3’-(G4T)3G3]. (b) Chart showing the integrated red fluorescence emission (595–800 nm, by 580-nm excitation) of the six NC-bearing strands

FIGURE 4 Optimization of an NCB by changing the length of stem on the interaction arm. (a) Schematic of stem length optimization. (b) Integrated fluorescence with and without the target and S/B ratio at different stem lengths. A stem length of three base pairs gave the highest S/B ratio of 175.

Design Aspects of Bright Red Emissive Silver Nanoclusters/

DNA Probes for MicroRNA Detection

Pratik Shah,Andreas Rorvig-Lund, Samir Ben Chaabane,Peter Waaben

Thulstrup

ACSNANO,2012, Published online

Figure 5 .Fluorescence intensity of the AgNCs formed after addition of AgNO3 and NaBH4 to a mixture containing 1.5 μM DNA-12nt-RED-160 probe and RNA-miR160 target in a concentration ranging from 0 to 1.5 μM. The fluorescence spectra were recorded,exciting at 560 nm.

Figure 6. (A) Emission spectra of the DNA-12nt-RED-160, 15nt (close to baseline), 18nt (close to baseline), 21nt, 22nt, and23nt. The emission spectra (excited at 560 nm) were recorded 1 h after mixing and reducing the DNA/AgNO3 mixture withNaBH4. (B) HRM analysis of 21nt, 22nt, 23nt, and A24. Native DNA without AgNCs was used in the HRM experiments, and theobserved green emission (monitored at 510 nm) is from the added SYBR green dye. (C) Native gel electrophoresis of (1) 21nt,(2) 22nt, (3) 23nt, (4) A24, and (5) A24/T24 1:1 ratio mixture. AgNO3 and NaBH4 were added to all the DNA samples beforerunning the gel electrophoresis experiment. SD: mismatch self-dimer or double-stranded DNA. H/S: hairpin and singlestrandedDNA. (D) Two suggested secondary DNA-12nt-RED-160 structures of a mismatch self-dimer and a hairpin with similar base pair interaction motif.

Figure 7. (A) Emission intensity of red emitting AgNCs formed with 10T, 15T, and 20T compared to DNA-12nt-RED-160, 1 h after creation at 25 C. (B) Emission intensity of red emitting AgNC formed by 10T, 1 h after creation at the specifiedtemperatures: 25, 42, 55, 65, and 75 C. (C) HRM analysis of DNA-12nt-RED-160, 10T, 15T, and 20T (no AgNCs were present here). (D) Native gel electrophoresis of (1) DNA-12nt-RED-160, (2) 10T, (3) 15T, and (4) 20T.AgNO3 and NaBH4 were added to all the DNA samples before running the gel electrophoresis experiment. SD: mismatch self-dimer or double-stranded DNA. H/S:hairpin and single-stranded DNA.

Figure 8. (A) Emission spectra of DNA-GG172-12nt-RED, excited at 540 nm, recorded 1 h after creation at the specified temperatures: 25, 42, 55, 65, and 75 C. (B) Emission spectra of DNA-12nt-RED-172 (black curve) and DNA-12nt-RED-172GG(red curve) excited at 540 nm, recorded 1 h after creation at 25 C. (C) Fluorescence intensity of the AgNCs formed after addition of AgNO3 and NaBH4 to a mixture containing 1.5 μM DNA-GG172-12nt-RED probe and RNA-miR172 target in a concentration ranging from 0 to 1.5 μM. The fluorescence spectra were recorded, exciting at 560 nm. The inset shows the SternVolmer plot. (D) Native gel electrophoresis of (1) DNA-GG172-12nt-RED, (2) DNA-12nt-RED-172, and (3) DNA-12nt-RED-172GG. SD: mismatch self-dimer or double-stranded DNA. H/S: hairpin and single-stranded DNA.

A DNA-templated fluorescent silver nanocluster with enhanced stability

Jaswinder Sharma,a Reginaldo C. Rocha,a M. Lisa Phipps,etl

Nanoscale, 2012, 4, 4107–4110

Fig. 9 D-AgNC is more stable than preceding AgNCs. (a) Photographs showing the fluorescence of AgNCs at different time intervals. (b) Table showing integrated fluorescence. The apparent fluorescence increase for J15 results from oxidation and blue shifting.

Fig. 10 Stability of D-AgNC with time and temperature. (a) Photographs and percent fluorescence (relative to initial intensity) as a function of time. (b) Fluorescence as a function of temperature.

Figure 11. Stability of D-AgNC with change in pH. a) Effect of pH on stability and emission intensity of DAgNC,b) Samples were synthesized at pH 3, 4, and 5, and after 72 hours the pH was raised to 7 and the fluorescence monitored.

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