Phenaz-TMA

Fig. 5.14 (a) Absorption spectra taken during titration of Phenaz-TMA/AuNPs with A-DNA and (b) their difference spectra. Here 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, and 50p.L of DNA (4.5 ng p-L ) solutions were added to 3 mL of Phenaz-TMA/AuNP (143 p,g mL ) aqueous solution. Reprinted with permission from [80]. Copyright (2010) by the Japan Society for Analytical Chemistry... 

Fig. 5.15 AFM images of Phenaz-TMA/AuNPs assembled on DNA. (a) Image in a large scan range, (b) Image in a smaller scan range, (c) Scan profile along the white arrow in image (b)...

The formation process for long metallic nanoarrays with DNA nanofibers is illustrated in Fig. 5.16 [80, 109]. First, a mixture of Phenaz-TMA/AuNPs and A-DNA in a TE buffer (pH = 8) solution was added to 8 i,L of ethanol. This solution was then deposited on a PDMS sheet, which was tilted at 15° during solvent evaporation to move the drying front downwards. Solvent evaporation leads to a decrease in the volume of the solution, leaving behind line patterns. Line patterns of metallic nanoarrays were formed when DNA with AuNPs attached was continuously deposited at the highly concentrated finger positions. Metallic nanoarrays also exceed several hundred micrometers in length and can be made within 30 min. 

Fig. 5.19 Dark-field optical microscopy images of Phenaz-TMA/AuNPs (a) before attaching DNA and (b) after attaching DNA. (c) Scattering spectra of spots 1, 2,3 and 4 in both images, (d) Schematic diagram of plasmon resonance energy induced by near-field coupling between MNPs...

Phenaz-TMA/AuNPs on DNA and theLPR color changes involved. Furthermore, it was possible to create 2D patterns of metallic nanoarrays by the TP technique. Our methods summarized here do not require any special equipments, and should provide a useful system for investigating the electromagnetic (light) field localized between MNPs. 

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