scholarly journals Effect of Random Nanostructured Metallic Environments on Spontaneous Emission of HITC Dye

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2135
Author(s):  
Sangeeta Rout ◽  
Zhen Qi ◽  
Ludvig S. Petrosyan ◽  
Tigran V. Shahbazyan ◽  
Monika M. Biener ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Theoretical Model ◽  
Spontaneous Emission ◽  
Concentration Quenching ◽  
Decay Rates ◽  
Laser Dye ◽  
Strongly Coupled ◽  
Strong Energy ◽  
Concentration Quenching Of Luminescence ◽  
Kinetics Of

We have studied emission kinetics of HITC laser dye on top of glass, smooth Au films, and randomly structured porous Au nanofoams. The observed concentration quenching of luminescence of highly concentrated dye on top of glass (energy transfer to acceptors) and the inhibition of the concentration quenching in vicinity of smooth Au films were in accord with our recent findings. Intriguingly, the emission kinetics recorded in different local spots of the Au nanofoam samples had a spread of the decay rates, which was large at low dye concentrations and became narrower with increase of the dye concentration. We infer that in different subvolumes of Au nanofoams, HITC molecules are coupled to the nanofoams weaker or stronger. The inhibition of the concentration quenching in Au nanofoams was stronger than on top of smooth Au films. This was true for all weakly and strongly coupled subvolumes contributing to the spread of the emission kinetics. The experimental observations were explained using theoretical model accounting for change in the Förster radius caused by the strong energy transfer to metal.

Effect of metal-dielectric environments on spontaneous emission and concentration quenching of HITC laser dye

2021 ◽  
Author(s):  
Sangeeta Rout ◽  
Samantha R. Koutsares ◽  
Srujana Prayakarao ◽  
Devon Courtwright ◽  
Vanessa Peters ◽  
...  
Keyword(s):  
Spontaneous Emission ◽  
Concentration Quenching ◽  
Laser Dye

scholarly journals Effect of nanoscale dielectric environments on concentration quenching

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sangeeta Rout ◽  
Samantha R. Koutsares ◽  
Devon Courtwright ◽  
Ezekiel Mills ◽  
Ayanna Shorter ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Diffusion Length ◽  
Porous Alumina ◽  
Concentration Quenching ◽  
Polymeric Films ◽  
Dye Molecules ◽  
Alumina Membranes ◽  
Concentration Quenching Of Luminescence ◽  
Effective Reduction ◽  
Donor Acceptor

Abstract We have studied the dependence of concentration quenching of luminescence (donor–acceptor energy transfer) on the thickness d of dye-doped polymeric films (HITC:PMMA) and found its strong inhibition at small values of d. This phenomenon is tentatively explained by a limited number of acceptors, which donors’ excitation can reach in thin samples, if the film’s thickness is comparable to the diffusion length of the energy transfer. The latter mechanism, along with effective reduction of the dye concentration, is responsible for an inhibition of the concentration quenching of dye molecules impregnating porous alumina membranes. The elongation of emission kinetics in thick (≥3 μm) HITC:PMMA films is cautiously attributed to the samples’ crystallinity.

Control of Förster energy transfer in the vicinity of metallic surfaces and hyperbolic metamaterials

2015 ◽  
Vol 178 ◽  
pp. 395-412 ◽  
Author(s):  
T. U. Tumkur ◽  
J. K. Kitur ◽  
C. E. Bonner ◽  
A. N. Poddubny ◽  
E. E. Narimanov ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Spontaneous Emission ◽  
Practical Importance ◽  
Index Of Refraction ◽  
Metallic Surfaces ◽  
Dielectric Media ◽  
Plasmonic Structures ◽  
Donor And Acceptor ◽  
Förster Energy Transfer ◽  
Photonic States

Optical cavities, plasmonic structures, photonic band crystals and interfaces, as well as, generally speaking, any photonic media with homogeneous or spatially inhomogeneous dielectric permittivity (including metamaterials) have local densities of photonic states, which are different from that in vacuum. These modified density of states environments are known to control both the rate and the angular distribution of spontaneous emission. In the present study, we question whether the proximity to metallic and metamaterial surfaces can affect other physical phenomena of fundamental and practical importance. We show that the same substrates and the same nonlocal dielectric environments that boost spontaneous emission, also inhibit Förster energy transfer between donor and acceptor molecules doped into a thin polymeric film. This finding correlates with the fact that in dielectric media, the rate of spontaneous emission is proportional to the index of refractionn, while the rate of the donor–acceptor energy transfer (in solid solutions with a random distribution of acceptors) is proportional ton−1.5. This heuristic correspondence suggests that other classical and quantum phenomena, which in regular dielectric media depend onn, can also be controlled with custom-tailored metamaterials, plasmonic structures, and cavities.

scholarly journals Determinants of mRNA stability in Dictyostelium discoideum amoebae: differences in poly(A) tail length, ribosome loading, and mRNA size cannot account for the heterogeneity of mRNA decay rates.

1988 ◽  
Vol 8 (5) ◽  
pp. 1957-1969 ◽  
Author(s):  
R A Shapiro ◽  
D Herrick ◽  
R E Manrow ◽  
D Blinder ◽  
A Jacobson
Keyword(s):  
Steady State ◽  
Dictyostelium Discoideum ◽  
Mrna Decay ◽  
Decay Rates ◽  
Time Dependent ◽  
Translational Efficiency ◽  
Cdna Clones ◽  
Dependent Manner ◽  
Significant Difference ◽  
Kinetics Of

As an approach to understanding the structures and mechanisms which determine mRNA decay rates, we have cloned and begun to characterize cDNAs which encode mRNAs representative of the stability extremes in the poly(A)+ RNA population of Dictyostelium discoideum amoebae. The cDNA clones were identified in a screening procedure which was based on the occurrence of poly(A) shortening during mRNA aging. mRNA half-lives were determined by hybridization of poly(A)+ RNA, isolated from cells labeled in a 32PO4 pulse-chase, to dots of excess cloned DNA. Individual mRNAs decayed with unique first-order decay rates ranging from 0.9 to 9.6 h, indicating that the complex decay kinetics of total poly(A)+ RNA in D. discoideum amoebae reflect the sum of the decay rates of individual mRNAs. Using specific probes derived from these cDNA clones, we have compared the sizes, extents of ribosome loading, and poly(A) tail lengths of stable, moderately stable, and unstable mRNAs. We found (i) no correlation between mRNA size and decay rate; (ii) no significant difference in the number of ribosomes per unit length of stable versus unstable mRNAs, and (iii) a general inverse relationship between mRNA decay rates and poly(A) tail lengths. Collectively, these observations indicate that mRNA decay in D. discoideum amoebae cannot be explained in terms of random nucleolytic events. The possibility that specific 3'-structural determinants can confer mRNA instability is suggested by a comparison of the labeling and turnover kinetics of different actin mRNAs. A correlation was observed between the steady-state percentage of a given mRNA found in polysomes and its degree of instability; i.e., unstable mRNAs were more efficiently recruited into polysomes than stable mRNAs. Since stable mRNAs are, on average, "older" than unstable mRNAs, this correlation may reflect a translational role for mRNA modifications that change in a time-dependent manner. Our previous studies have demonstrated both a time-dependent shortening and a possible translational role for the 3' poly(A) tracts of mRNA. We suggest, therefore, that the observed differences in the translational efficiency of stable and unstable mRNAs may, in part, be attributable to differences in steady-state poly(A) tail lengths.

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