Behaviour of Pseudoisocyanine in Macromolecular and Hydrotropic Solutions

Menegussi, Lukese Rosa; Valandro, Silvano R.; Poli, Alessandra Lima; Cavalheiro, Carla Cristina Schmitt; Neumann, Miguel G.

doi:10.5935/0103-5053.20140128

Cited by 4 publications

(7 citation statements)

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“…The intensity of the PIC emission is, however, almost 2 orders of magnitude higher in ATA duplexes than in aqueous buffer, presumably because of the interaction of PIC with ATA duplexes. The decay pathway to the ground state through free rotation of the two quinonlinic rings of PIC is reduced upon binding to DNA and hence the fluorescence intensity increases relative to that in water . Thus, there are really three forms of PIC in these samples: PIC in DNA-templated aggregates, PIC nonspecifically bound to DNA, and PIC free in solution.…”

Section: Resultsmentioning

confidence: 99%

“…The decay pathway to the ground state through free rotation of the two quinonlinic rings of PIC is reduced upon binding to DNA and hence the fluorescence intensity increases relative to that in water. 40 Thus, there are really three forms of PIC in these samples: PIC in DNA-templated aggregates, PIC nonspecifically bound to DNA, and PIC free in solution. The fluorescence excitation spectra monitored at 600 nm were compared for all samples (Figure S2a-c).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Directed Energy Transfer through DNA-Templated J-Aggregates

et al. 2019

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Strongly coupled molecular dye aggregates have unique optoelectronic properties that often resemble those of light harvesting complexes found in Nature. The exciton dynamics in coupled dye aggregates could enhance the longrange transfer of optical excitation energy with high efficiency. In principle, dye aggregates could serve as important components in molecular-scale photonic devices; however, rational design of these coupled dye aggregates with precise control over their organization, interactions, and dynamics remains a challenge. DNA nanotechnology has recently been used to build an excitonic circuit by organizing pseudoisocyanine (PIC) dyes forming J-aggregates on the templates of poly(dA)-poly(dT) DNA duplexes. Here, the excitonic properties of the PIC Jaggregates on DNA are characterized spectroscopically in detail using poly(dA)-poly(dT) tract lengths of 24 and 48 base pairs. The excitonic properties of these DNA templated dye assemblies depend on the length and sequence of the DNA template. The incorporation of a gap of two GC base pairs between two segments of poly(dA)-poly(dT) DNA markedly reduces the delocalization of excitation in the J-aggregates. With a quantum dot (QD) as the light absorber and energy donor and using Alexa Fluor 647 (AF647) as the energy acceptor, with a DNAtemplated J-aggregate in between, significant energy transfer from QD to AF647 is observed over a distance far longer than possible without the aggregate bridge. By comparing the efficiency of energy transfer through a continuous J-aggregate with the efficiency when the aggregate has a discontinuity in the middle, the effects of energy transfer within the aggregate bridge between the donor and acceptor are evaluated.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Directed Energy Transfer through DNA-Templated J-Aggregates

et al. 2019

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“…ICY is a cationic dye that exhibits two absorption bands in the visible spectral range with maxima at 520 and 556 nm in aqueous solution (Figure ). The ICY molecules in aqueous solution exhibited a low fluorescence emission (Φ < 0.5%) with maxima at 565 and 605 nm (Figure ) due to the rotational relaxation of the molecules, which competes with the radiant relaxation. , …”

Section: Resultsmentioning

confidence: 99%

“…This phenomenon is due to the interaction of ICY molecules with the clay surface, which restricts the degree of freedom of the dye. Therefore, this restriction decreases the degree of the radiationless process, providing high fluorescence emission. ,, …”

Section: Resultsmentioning

confidence: 99%

Photophysical Behavior of Isocyanine/Clay Hybrids in the Solid State

et al. 2017

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In the present study, we have attempted to investigate, for the first time, the photophysical behavior of 1,1'-diethyl-2,4'-cyanine (ICY)/clay mineral hybrids in the solid state. The effects promoted by ICY loading and clay type on the spectroscopic properties were studied by UV-vis diffuse reflectance spectroscopy (DR) and different fluorescence techniques. The hybrids were characterized by X-ray diffraction (XRD) and thermogravimetric analysis (TGA). UV-vis-DR revealed the formation of ICY H-aggregates in Wyoming montmorillonite (SWy-1) and Laponite (Lap); however, J-aggregates were predominant for ICY on Arizona (SAz-1) and Barasym (SYn-1) montmorillonites. The formation of J-aggregates was favored on clays with a high layer charge density (SAz-1 and SYn-1). Increasing ICY loading leads to an increase in H-aggregates, which become predominant in all of the samples. The fluorescence spectra of ICY-Lap and ICY-SYn-1 hybrids showed two emissive bands, and they were assigned to the monomeric and J-aggregate species. The fluorescence lifetime showed consistent and distinct values for the two species. The longer fluorescence lifetime can be assigned to the ICY monomers, while the second component has a short lifetime value and may be attributed to J-aggregate emission species. Moreover, confocal fluorescence micrographs showed two different fluorescent domains; monomers (greenish domain) and J-aggregates (orange domain) can be clearly distinguished. For ICY adsorbed on SWy-1 and SAz-1, the intensities of the fluorescence spectra were very low, and it was not possible to measure the fluorescence lifetimes due to high iron content in these clays, which acts as an efficient quencher of the excited singlet state of the dye molecules. XRD and TGA curves showed that the intercalation of ICY into the interlayer regions of SWy-1, SAz-1, and SYn-1 occurred for high dye concentration only. In the case of Laponite, ICY adsorbs on the external surface of the layer. Our studies indicate that the ICY-clays, in particular, ICY-SYn-1 and ICY-Lap, are promising hybrid materials with interesting optical and photophysical properties.

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“…This increase in QY is speculated to be a result of DNA interactions constraining the available excited-state relaxation pathway by restricting the free rotation of quinolinic rings. 43 Assuming this elevated QY, R 0 increases to 2.6 nm and the predicted energy transfer increases to 62.4% in the OV scaffold and 26.8% transfer in all other scaffolds. These values however assume no energy loss from transfer through D and relay.…”

Section: ■ Methodsmentioning

confidence: 97%

Understanding Self-Assembled Pseudoisocyanine Dye Aggregates in DNA Nanostructures and Their Exciton Relay Transfer Capabilities

et al. 2021

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Progress has been made using B-form DNA duplex strands to template chromophores in ordered molecular aggregates known as J-aggregates. These aggregates can exhibit strong electronic coupling, extended coherent lifetimes, and long-range exciton delocalization under appropriate conditions. Certain cyanine dyes such as pseudoisocyanine (PIC) dye have shown a proclivity to form aggregates in specific DNA sequences. In particular, DX-tiles containing nonalternating poly(dA)–poly(dT) dinucleotide tracks (AT-tracks), which template noncovalent PIC dye aggregates, have been demonstrated to exhibit interesting emergent photonic properties. These DNA-based aggregates are referred to as J-bits for their similarity to J-aggregates. Here, we assemble multifluorophore DX-tile scaffolds which template J-bits into both contiguous and noncontiguous linear arrays. Our goal is to understand the relay capability of noncontiguous J-bit arrays and probe the effects that orientation and position have on the energy transfer between them. We find that linearly contiguous J-bits can relay excitons from an initial AlexaFluor 405 donor to a terminal AlexaFluor 647 acceptor across a distance of up to 16.3 nm. We observed a maximum increase in energy transfer of 41% in the shortest scaffold and an 11% increase in energy transfer across the maximum distance. However, in nonlinear arrays, exciton transfer is not detectable, even when off-axis J-bit-to-J-bit transfer distances were <2 nm. These results, in conjunction with the previous work on PIC–DNA systems, suggest that PIC–DNA-based systems may currently be limited to simple 1-D designs, which prevent isolating J-bits for enhanced energy-transfer characteristics until further understanding and improvements to the system can be made.

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Behaviour of Pseudoisocyanine in Macromolecular and Hydrotropic Solutions

Cited by 4 publications

References 2 publications

Directed Energy Transfer through DNA-Templated J-Aggregates

Directed Energy Transfer through DNA-Templated J-Aggregates

Photophysical Behavior of Isocyanine/Clay Hybrids in the Solid State

Understanding Self-Assembled Pseudoisocyanine Dye Aggregates in DNA Nanostructures and Their Exciton Relay Transfer Capabilities

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