| 18. | L Grabenhorst, K Trofymchuk, F Steiner, V Glembockyte, P Tinnefeld Fluorophore photostability and saturation in the hotspot of DNA origami nanoantennas Journal Article Methods and Applications in Fluorescence, 8 (2), pp. 024003, 2020, ISSN: 2050-6120. Abstract | Links | Tags: Foundry Organic, Molecularly-Functionalized @article{, title = {Fluorophore photostability and saturation in the hotspot of DNA origami nanoantennas}, author = {L Grabenhorst and K Trofymchuk and F Steiner and V Glembockyte and P Tinnefeld}, url = {http://dx.doi.org/10.1088/2050-6120/ab6ac8}, doi = {10.1088/2050-6120/ab6ac8}, issn = {2050-6120}, year = {2020}, date = {2020-02-05}, journal = {Methods and Applications in Fluorescence}, volume = {8}, number = {2}, pages = {024003}, abstract = {Fluorescent dyes used for single-molecule spectroscopy can undergo millions of excitation-emission cycles before photobleaching. Due to the upconcentration of light in a plasmonic hotspot, the conditions for fluorescent dyes are even more demanding in DNA origami nanoantennas. Here, we briefly review the current state of fluorophore stabilization for single-molecule imaging and reveal additional factors relevant in the context of plasmonic fluorescence enhancement. We show that despite the improved photostability of single-molecule fluorophores by DNA origami nanoantennas, their performance in the intense electric fields in plasmonic hotspots is still limited by the underlying photophysical processes, such as formation of dim states and photoisomerization. These photophysical processes limit the photon count rates, increase heterogeneity and aggravate quantification of fluorescence enhancement factors. These factors also reduce the time resolution that can be achieved in biophysical single-molecule experiments. Finally, we show how the photophysics of a DNA hairpin assay with a fluorophore-quencher pair can be influenced by plasmonic DNA origami nanoantennas leading to implications for their use in fluorescence-based diagnostic assays. Especially, we show that such assays can produce false positive results by premature photobleaching of the dark quencher.}, keywords = {Foundry Organic, Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } Fluorescent dyes used for single-molecule spectroscopy can undergo millions of excitation-emission cycles before photobleaching. Due to the upconcentration of light in a plasmonic hotspot, the conditions for fluorescent dyes are even more demanding in DNA origami nanoantennas. Here, we briefly review the current state of fluorophore stabilization for single-molecule imaging and reveal additional factors relevant in the context of plasmonic fluorescence enhancement. We show that despite the improved photostability of single-molecule fluorophores by DNA origami nanoantennas, their performance in the intense electric fields in plasmonic hotspots is still limited by the underlying photophysical processes, such as formation of dim states and photoisomerization. These photophysical processes limit the photon count rates, increase heterogeneity and aggravate quantification of fluorescence enhancement factors. These factors also reduce the time resolution that can be achieved in biophysical single-molecule experiments. Finally, we show how the photophysics of a DNA hairpin assay with a fluorophore-quencher pair can be influenced by plasmonic DNA origami nanoantennas leading to implications for their use in fluorescence-based diagnostic assays. Especially, we show that such assays can produce false positive results by premature photobleaching of the dark quencher. |
| 17. | D Ruhstorfer, S Mejia, M Ramsteiner, M Döblinger, H Riedl, J J Finley, G Koblmüller Demonstration of n-type behavior in catalyst-free Si-doped GaAs nanowires grown by molecular beam epitaxy Journal Article Applied Physics Letters, 116 (5), pp. 052101, 2020. Links | Tags: Foundry Inorganic, Molecularly-Functionalized @article{, title = {Demonstration of n-type behavior in catalyst-free Si-doped GaAs nanowires grown by molecular beam epitaxy}, author = {D Ruhstorfer and S Mejia and M Ramsteiner and M D\"{o}blinger and H Riedl and J J Finley and G Koblm\"{u}ller}, url = {https://aip.scitation.org/doi/abs/10.1063/1.5134687}, doi = {10.1063/1.5134687}, year = {2020}, date = {2020-02-04}, journal = {Applied Physics Letters}, volume = {116}, number = {5}, pages = {052101}, keywords = {Foundry Inorganic, Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } |
| 16. | W J Li, S Xue, S Watzele, S J Hou, J Fichtner, A L Semrau, L J Zhou, A Welle, A S Bandarenka, R A Fischer Advanced Bifunctional Oxygen Reduction and Evolution Electrocatalyst Derived from Surface-Mounted Metal-Organic Frameworks Journal Article Angewandte Chemie-International Edition, 2020, ISSN: 1433-7851. Links | Tags: Molecularly-Functionalized, Solid-Liquid @article{, title = {Advanced Bifunctional Oxygen Reduction and Evolution Electrocatalyst Derived from Surface-Mounted Metal-Organic Frameworks}, author = {W J Li and S Xue and S Watzele and S J Hou and J Fichtner and A L Semrau and L J Zhou and A Welle and A S Bandarenka and R A Fischer}, url = {<Go to ISI>://WOS:000509752400001}, doi = {10.1002/anie.201916507}, issn = {1433-7851}, year = {2020}, date = {2020-01-08}, journal = {Angewandte Chemie-International Edition}, keywords = {Molecularly-Functionalized, Solid-Liquid}, pubstate = {published}, tppubtype = {article} } |
| 15. | C Heshmatpour, J Hauer, F Sanda Interplay of exciton annihilation and transport in fifth order electronic spectroscopy Journal Article Chemical Physics, 528 , 2020, ISSN: 0301-0104. Links | Tags: Molecularly-Functionalized, Solid-Liquid @article{, title = {Interplay of exciton annihilation and transport in fifth order electronic spectroscopy}, author = {C Heshmatpour and J Hauer and F Sanda}, url = {<Go to ISI>://WOS:000490758300009}, doi = {10.1016/j.chemphys.2019.110433}, issn = {0301-0104}, year = {2020}, date = {2020-01-01}, journal = {Chemical Physics}, volume = {528}, keywords = {Molecularly-Functionalized, Solid-Liquid}, pubstate = {published}, tppubtype = {article} } |
| 14. | J Schedlbauer, P Wilhelm, L Grabenhorst, M E Federl, B Lalkens, F Hinderer, U Scherf, S Höger, P Tinnefeld, S Bange, J Vogelsang, J M Lupton Ultrafast Single-Molecule Fluorescence Measured by Femtosecond Double-Pulse Excitation Photon Antibunching Journal Article Nano Letters, 2019, ISSN: 1530-6984. Links | Tags: Foundry Organic, Molecularly-Functionalized @article{, title = {Ultrafast Single-Molecule Fluorescence Measured by Femtosecond Double-Pulse Excitation Photon Antibunching}, author = {J Schedlbauer and P Wilhelm and L Grabenhorst and M E Federl and B Lalkens and F Hinderer and U Scherf and S H\"{o}ger and P Tinnefeld and S Bange and J Vogelsang and J M Lupton}, url = {https://doi.org/10.1021/acs.nanolett.9b04354}, doi = {10.1021/acs.nanolett.9b04354}, issn = {1530-6984}, year = {2019}, date = {2019-12-23}, journal = {Nano Letters}, keywords = {Foundry Organic, Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } |
| 13. | Y Negrín-Montecelo, M Comesaña-Hermo, L K Khorashad, A Sousa-Castillo, Z Wang, M Pérez-Lorenzo, T Liedl, A O Govorov, M A Correa-Duarte ACS Energy Letters, pp. 395-402, 2019. Links | Tags: Foundry Inorganic, Molecularly-Functionalized @article{, title = {Photophysical Effects behind the Efficiency of Hot Electron Injection in Plasmon-Assisted Catalysis: The Joint Role of Morphology and Composition}, author = {Y Negr\'{i}n-Montecelo and M Comesa\~{n}a-Hermo and L K Khorashad and A Sousa-Castillo and Z Wang and M P\'{e}rez-Lorenzo and T Liedl and A O Govorov and M A Correa-Duarte}, url = {https://doi.org/10.1021/acsenergylett.9b02478}, doi = {10.1021/acsenergylett.9b02478}, year = {2019}, date = {2019-12-12}, journal = {ACS Energy Letters}, pages = {395-402}, keywords = {Foundry Inorganic, Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } |
| 12. | S Fust, A Faustmann, D J Carrad, J Bissinger, B Loitsch, M Döblinger, J Becker, G Abstreiter, J J Finley, G Koblmüller Quantum-Confinement-Enhanced Thermoelectric Properties in Modulation-Doped GaAs–AlGaAs Core–Shell Nanowires Journal Article Advanced Materials, 32 (4), pp. 1905458, 2019, ISSN: 0935-9648. Abstract | Links | Tags: Foundry Inorganic, Molecularly-Functionalized @article{, title = {Quantum-Confinement-Enhanced Thermoelectric Properties in Modulation-Doped GaAs\textendashAlGaAs Core\textendashShell Nanowires}, author = {S Fust and A Faustmann and D J Carrad and J Bissinger and B Loitsch and M D\"{o}blinger and J Becker and G Abstreiter and J J Finley and G Koblm\"{u}ller}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201905458}, doi = {10.1002/adma.201905458}, issn = {0935-9648}, year = {2019}, date = {2019-12-09}, journal = {Advanced Materials}, volume = {32}, number = {4}, pages = {1905458}, abstract = {Abstract Nanowires (NWs) hold great potential in advanced thermoelectrics due to their reduced dimensions and low-dimensional electronic character. However, unfavorable links between electrical and thermal conductivity in state-of-the-art unpassivated NWs have, so far, prevented the full exploitation of their distinct advantages. A promising model system for a surface-passivated one-dimensional (1D)-quantum confined NW thermoelectric is developed that enables simultaneously the observation of enhanced thermopower via quantum oscillations in the thermoelectric transport and a strong reduction in thermal conductivity induced by the core\textendashshell heterostructure. High-mobility modulation-doped GaAs/AlGaAs core\textendashshell NWs with thin (sub-40 nm) GaAs NW core channel are employed, where the electrical and thermoelectric transport is characterized on the same exact 1D-channel. 1D-sub-band transport at low temperature is verified by a discrete stepwise increase in the conductance, which coincided with strong oscillations in the corresponding Seebeck voltage that decay with increasing sub-band number. Peak Seebeck coefficients as high as ≈65\textendash85 µV K−1 are observed for the lowest sub-bands, resulting in equivalent thermopower of S2σ ≈ 60 µW m−1 K−2 and S2G ≈ 0.06 pW K−2 within a single sub-band. Remarkably, these core\textendashshell NW heterostructures also exhibit thermal conductivities as low as ≈3 W m−1 K−1, about one order of magnitude lower than state-of-the-art unpassivated GaAs NWs.}, keywords = {Foundry Inorganic, Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } Abstract Nanowires (NWs) hold great potential in advanced thermoelectrics due to their reduced dimensions and low-dimensional electronic character. However, unfavorable links between electrical and thermal conductivity in state-of-the-art unpassivated NWs have, so far, prevented the full exploitation of their distinct advantages. A promising model system for a surface-passivated one-dimensional (1D)-quantum confined NW thermoelectric is developed that enables simultaneously the observation of enhanced thermopower via quantum oscillations in the thermoelectric transport and a strong reduction in thermal conductivity induced by the core–shell heterostructure. High-mobility modulation-doped GaAs/AlGaAs core–shell NWs with thin (sub-40 nm) GaAs NW core channel are employed, where the electrical and thermoelectric transport is characterized on the same exact 1D-channel. 1D-sub-band transport at low temperature is verified by a discrete stepwise increase in the conductance, which coincided with strong oscillations in the corresponding Seebeck voltage that decay with increasing sub-band number. Peak Seebeck coefficients as high as ≈65–85 µV K−1 are observed for the lowest sub-bands, resulting in equivalent thermopower of S2σ ≈ 60 µW m−1 K−2 and S2G ≈ 0.06 pW K−2 within a single sub-band. Remarkably, these core–shell NW heterostructures also exhibit thermal conductivities as low as ≈3 W m−1 K−1, about one order of magnitude lower than state-of-the-art unpassivated GaAs NWs. |
| 11. | M Kick, H Oberhofer Towards a transferable design of solid-state embedding models on the example of a rutile TiO2 (110) surface Journal Article Journal of Chemical Physics, 151 (18), 2019, ISSN: 0021-9606. Links | Tags: Molecularly-Functionalized, Solid-Liquid @article{, title = {Towards a transferable design of solid-state embedding models on the example of a rutile TiO2 (110) surface}, author = {M Kick and H Oberhofer}, url = {<Go to ISI>://WOS:000497760200011}, doi = {10.1063/1.5125204}, issn = {0021-9606}, year = {2019}, date = {2019-11-14}, journal = {Journal of Chemical Physics}, volume = {151}, number = {18}, keywords = {Molecularly-Functionalized, Solid-Liquid}, pubstate = {published}, tppubtype = {article} } |
| 10. | J Treu, X Xu, K Ott, K Saller, G Abstreiter, J J Finley, G Koblmüller Optical absorption of composition-tunable InGaAs nanowire arrays Journal Article Nanotechnology, 30 (49), pp. 495703, 2019, ISSN: 0957-4484 1361-6528. Abstract | Links | Tags: Foundry Inorganic, Molecularly-Functionalized @article{, title = {Optical absorption of composition-tunable InGaAs nanowire arrays}, author = {J Treu and X Xu and K Ott and K Saller and G Abstreiter and J J Finley and G Koblm\"{u}ller}, url = {http://dx.doi.org/10.1088/1361-6528/ab3ef7}, doi = {10.1088/1361-6528/ab3ef7}, issn = {0957-4484 1361-6528}, year = {2019}, date = {2019-09-20}, journal = {Nanotechnology}, volume = {30}, number = {49}, pages = {495703}, abstract = {InGaAs nanowire (NW) arrays have emerged as important active materials in future photovoltaic and photodetector applications, due to their excellent electronic properties and tunable band gap. Here, we report a systematic investigation of the optical absorption characteristics of composition-tunable vertical InGaAs NW arrays. Using finite-difference time-domain simulations we first study the effect of variable composition (Ga-molar fraction) and NW array geometry (NW diameter, period, fill factor) on the optical generation rate. NWs with typical diameters in the range of ∼100\textendash250 nm lead to generation rates higher than the equivalent bulk case for moderate fill factors (NW period of ∼0.3\textendash0.8 μm), while slightly smaller fill factors and increased diameters are required to maintain high generation rates at increased Ga-molar fraction. The optical absorption was further measured using spectrally resolved ultraviolet\textendashvisible-near-infrared (UV\textendashvis-NIR) spectroscopy on NW arrays transferred to transparent substrates. Interestingly, large variations in Ga-molar fraction (0 < x(Ga) < 0.5) have a negligible influence, while minute changes in NW diameter of less than ±20 nm affect the absorption spectra very strongly, leading to pronounced shifts in the peak absorption energies by more than ∼700 meV. These results clearly highlight the much larger sensitivity of the optical absorption behavior to geometric parameters rather than to variations in the electronic band gap of the underlying NW array.}, keywords = {Foundry Inorganic, Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } InGaAs nanowire (NW) arrays have emerged as important active materials in future photovoltaic and photodetector applications, due to their excellent electronic properties and tunable band gap. Here, we report a systematic investigation of the optical absorption characteristics of composition-tunable vertical InGaAs NW arrays. Using finite-difference time-domain simulations we first study the effect of variable composition (Ga-molar fraction) and NW array geometry (NW diameter, period, fill factor) on the optical generation rate. NWs with typical diameters in the range of ∼100–250 nm lead to generation rates higher than the equivalent bulk case for moderate fill factors (NW period of ∼0.3–0.8 μm), while slightly smaller fill factors and increased diameters are required to maintain high generation rates at increased Ga-molar fraction. The optical absorption was further measured using spectrally resolved ultraviolet–visible-near-infrared (UV–vis-NIR) spectroscopy on NW arrays transferred to transparent substrates. Interestingly, large variations in Ga-molar fraction (0 < x(Ga) < 0.5) have a negligible influence, while minute changes in NW diameter of less than ±20 nm affect the absorption spectra very strongly, leading to pronounced shifts in the peak absorption energies by more than ∼700 meV. These results clearly highlight the much larger sensitivity of the optical absorption behavior to geometric parameters rather than to variations in the electronic band gap of the underlying NW array. |
| 9. | K Hübner, M Pilo-Pais, F Selbach, T Liedl, P Tinnefeld, F D Stefani, G P Acuna Directing Single-Molecule Emission with DNA Origami-Assembled Optical Antennas Journal Article Nano Letters, 19 (9), pp. 6629-6634, 2019, ISSN: 1530-6984. Links | Tags: Foundry Organic, Molecularly-Functionalized @article{, title = {Directing Single-Molecule Emission with DNA Origami-Assembled Optical Antennas}, author = {K H\"{u}bner and M Pilo-Pais and F Selbach and T Liedl and P Tinnefeld and F D Stefani and G P Acuna}, url = {https://doi.org/10.1021/acs.nanolett.9b02886}, doi = {10.1021/acs.nanolett.9b02886}, issn = {1530-6984}, year = {2019}, date = {2019-09-11}, journal = {Nano Letters}, volume = {19}, number = {9}, pages = {6629-6634}, keywords = {Foundry Organic, Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } |
| 8. | J Gargiulo, R Berté, Y Li, S A Maier, E Cortés From Optical to Chemical Hot Spots in Plasmonics Journal Article Accounts of Chemical Research, 2019, ISSN: 0001-4842. Links | Tags: Molecularly-Functionalized @article{, title = {From Optical to Chemical Hot Spots in Plasmonics}, author = {J Gargiulo and R Bert\'{e} and Y Li and S A Maier and E Cort\'{e}s}, url = {https://doi.org/10.1021/acs.accounts.9b00234}, doi = {10.1021/acs.accounts.9b00234}, issn = {0001-4842}, year = {2019}, date = {2019-08-20}, journal = {Accounts of Chemical Research}, keywords = {Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } |
| 7. | K Kratzl, T Kratky, S Gunther, O Tomanec, R Zboril, J Michalicka, J M Macak, M Cokoja, R A Fischer Generation and Stabilization of Small Platinum Clusters Pt-12 +/- x Inside a Metal-Organic Framework Journal Article Journal of the American Chemical Society, 141 (35), pp. 13962-13969, 2019, ISSN: 0002-7863. Links | Tags: Molecularly-Functionalized @article{, title = {Generation and Stabilization of Small Platinum Clusters Pt-12 +/- x Inside a Metal-Organic Framework}, author = {K Kratzl and T Kratky and S Gunther and O Tomanec and R Zboril and J Michalicka and J M Macak and M Cokoja and R A Fischer}, url = {<Go to ISI>://WOS:000484828900039}, doi = {10.1021/jacs.9b07083}, issn = {0002-7863}, year = {2019}, date = {2019-08-09}, journal = {Journal of the American Chemical Society}, volume = {141}, number = {35}, pages = {13962-13969}, keywords = {Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } |
| 6. | I Kaminska, J Bohlen, S Rocchetti, F Selbach, G P Acuna, P Tinnefeld Distance Dependence of Single-Molecule Energy Transfer to Graphene Measured with DNA Origami Nanopositioners Journal Article Nano Letters, 19 (7), pp. 4257-4262, 2019, ISSN: 1530-6984. Abstract | Links | Tags: Molecularly-Functionalized @article{, title = {Distance Dependence of Single-Molecule Energy Transfer to Graphene Measured with DNA Origami Nanopositioners}, author = {I Kaminska and J Bohlen and S Rocchetti and F Selbach and G P Acuna and P Tinnefeld}, url = {https://doi.org/10.1021/acs.nanolett.9b00172}, doi = {10.1021/acs.nanolett.9b00172}, issn = {1530-6984}, year = {2019}, date = {2019-07-10}, journal = {Nano Letters}, volume = {19}, number = {7}, pages = {4257-4262}, abstract = {Despite the thorough investigation of graphene since 2004, altering its surface chemistry and reproducible functionalization remain challenging. This hinders fabrication of more complex hybrid materials with controlled architectures, and as a consequence the development of sensitive and reliable sensors and biological assays. In this contribution, we introduce DNA origami structures as nanopositioners for placing single dye molecules at controlled distances from graphene. The measurements of fluorescence intensity and lifetime of single emitters carried out for distances ranging from 3 to 58 nm confirmed the d\textendash4 dependence of the excitation energy transfer to graphene. Moreover, we determined the characteristic distance for 50% efficiency of the energy transfer from single dyes to graphene to be 17.7 nm. Using pyrene molecules as a glue to immobilize DNA origami nanostructures of various shape on graphene opens new possibilities to develop graphene-based biophysics and biosensing.}, keywords = {Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } Despite the thorough investigation of graphene since 2004, altering its surface chemistry and reproducible functionalization remain challenging. This hinders fabrication of more complex hybrid materials with controlled architectures, and as a consequence the development of sensitive and reliable sensors and biological assays. In this contribution, we introduce DNA origami structures as nanopositioners for placing single dye molecules at controlled distances from graphene. The measurements of fluorescence intensity and lifetime of single emitters carried out for distances ranging from 3 to 58 nm confirmed the d–4 dependence of the excitation energy transfer to graphene. Moreover, we determined the characteristic distance for 50% efficiency of the energy transfer from single dyes to graphene to be 17.7 nm. Using pyrene molecules as a glue to immobilize DNA origami nanostructures of various shape on graphene opens new possibilities to develop graphene-based biophysics and biosensing. |
| 5. | C Muschielok, H Oberhofer Aspects of semiconductivity in soft, porous metal-organic framework crystals Journal Article Journal of Chemical Physics, 151 (1), 2019, ISSN: 0021-9606. Links | Tags: Foundry Organic, Molecularly-Functionalized @article{, title = {Aspects of semiconductivity in soft, porous metal-organic framework crystals}, author = {C Muschielok and H Oberhofer}, url = {<Go to ISI>://WOS:000474214600025}, doi = {10.1063/1.5108995}, issn = {0021-9606}, year = {2019}, date = {2019-07-03}, journal = {Journal of Chemical Physics}, volume = {151}, number = {1}, keywords = {Foundry Organic, Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } |
| 4. | S Reiter, M K Roos, R De Vivie-Riedle Excited State Conformations of Bridged and Unbridged Pyrene Excimers Journal Article Chemphotochem, 3 (9), pp. 881-888, 2019, ISSN: 2367-0932. Links | Tags: Molecularly-Functionalized @article{, title = {Excited State Conformations of Bridged and Unbridged Pyrene Excimers}, author = {S Reiter and M K Roos and R De Vivie-Riedle}, url = {<Go to ISI>://WOS:000487014600024}, doi = {10.1002/cptc.201900096}, issn = {2367-0932}, year = {2019}, date = {2019-05-06}, journal = {Chemphotochem}, volume = {3}, number = {9}, pages = {881-888}, keywords = {Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } |
| 3. | T Schröder, M B Scheible, F Steiner, J Vogelsang, P Tinnefeld Interchromophoric Interactions Determine the Maximum Brightness Density in DNA Origami Structures Journal Article Nano Letters, 19 (2), pp. 1275-1281, 2019, ISSN: 1530-6984. Abstract | Links | Tags: Molecularly-Functionalized @article{, title = {Interchromophoric Interactions Determine the Maximum Brightness Density in DNA Origami Structures}, author = {T Schr\"{o}der and M B Scheible and F Steiner and J Vogelsang and P Tinnefeld}, url = {https://doi.org/10.1021/acs.nanolett.8b04845}, doi = {10.1021/acs.nanolett.8b04845}, issn = {1530-6984}, year = {2019}, date = {2019-02-13}, journal = {Nano Letters}, volume = {19}, number = {2}, pages = {1275-1281}, abstract = {An ideal point light source is as small and as bright as possible. For fluorescent point light sources, homogeneity of the light sources is important as well as that the fluorescent units inside the light source maintain their photophysical properties, which is compromised by dye aggregation. Here we propose DNA origami as a rigid scaffold to arrange dye molecules in a dense pixel array with high control of stoichiometry and dye\textendashdye interactions. In order to find the highest labeling density in a DNA origami structure without influencing dye photophysics, we alter the distance of two ATTO647N dyes in single base pair steps and probe the dye\textendashdye interactions on the single-molecule level. For small distances strong quenching in terms of intensity and fluorescence lifetime is observed. With increasing distance, we observe reduced quenching and molecular dynamics. However, energy transfer processes in the weak coupling regime still have a significant impact and can lead to quenching by singlet-dark-state-annihilation. Our study fills a gap of studying the interactions of dyes relevant for superresolution microscopy with dense labeling and for single-molecule biophysics. Incorporating these findings in a 3D DNA origami object will pave the way to bright and homogeneous DNA origami nanobeads.}, keywords = {Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } An ideal point light source is as small and as bright as possible. For fluorescent point light sources, homogeneity of the light sources is important as well as that the fluorescent units inside the light source maintain their photophysical properties, which is compromised by dye aggregation. Here we propose DNA origami as a rigid scaffold to arrange dye molecules in a dense pixel array with high control of stoichiometry and dye–dye interactions. In order to find the highest labeling density in a DNA origami structure without influencing dye photophysics, we alter the distance of two ATTO647N dyes in single base pair steps and probe the dye–dye interactions on the single-molecule level. For small distances strong quenching in terms of intensity and fluorescence lifetime is observed. With increasing distance, we observe reduced quenching and molecular dynamics. However, energy transfer processes in the weak coupling regime still have a significant impact and can lead to quenching by singlet-dark-state-annihilation. Our study fills a gap of studying the interactions of dyes relevant for superresolution microscopy with dense labeling and for single-molecule biophysics. Incorporating these findings in a 3D DNA origami object will pave the way to bright and homogeneous DNA origami nanobeads. |
| 2. | J Li, E Tan, N Keller, Y-H Chen, P M Zehetmaier, A C Jakowetz, T Bein, P Knochel Cobalt-Catalyzed Electrophilic Aminations with Anthranils: An Expedient Route to Condensed Quinolines Journal Article Journal of the American Chemical Society, 141 (1), pp. 98-103, 2019, ISSN: 0002-7863. Abstract | Links | Tags: Molecularly-Functionalized @article{, title = {Cobalt-Catalyzed Electrophilic Aminations with Anthranils: An Expedient Route to Condensed Quinolines}, author = {J Li and E Tan and N Keller and Y-H Chen and P M Zehetmaier and A C Jakowetz and T Bein and P Knochel}, url = {https://doi.org/10.1021/jacs.8b11466}, doi = {10.1021/jacs.8b11466}, issn = {0002-7863}, year = {2019}, date = {2019-01-09}, journal = {Journal of the American Chemical Society}, volume = {141}, number = {1}, pages = {98-103}, abstract = {The reaction of various organozinc pivalates with anthranils provides anilines derivatives, which cyclize under acidic conditions providing condensed quinolines. Using alkenylzinc pivalates, electron-rich arylzinc pivalates or heterocyclic zinc pivalates produces directly the condensed quinolines of which several structures belong to new heterocyclic scaffolds. These N-heterocycles are of particular interest for organic light emitting diodes with their high photoluminescence quantum yields and long exciton lifetimes as well as for hole-transporting materials in methylammonium lead iodide perovskites solar cells due to an optimal band alignment for holes and a large bandgap.}, keywords = {Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } The reaction of various organozinc pivalates with anthranils provides anilines derivatives, which cyclize under acidic conditions providing condensed quinolines. Using alkenylzinc pivalates, electron-rich arylzinc pivalates or heterocyclic zinc pivalates produces directly the condensed quinolines of which several structures belong to new heterocyclic scaffolds. These N-heterocycles are of particular interest for organic light emitting diodes with their high photoluminescence quantum yields and long exciton lifetimes as well as for hole-transporting materials in methylammonium lead iodide perovskites solar cells due to an optimal band alignment for holes and a large bandgap. |
| 1. | K Trofymchuk, V Glembockyte, L Grabenhorst, F Steiner, C Vietz, C Close, M Pfeiffer, L Richter, M L Schütte, F Selbach, R Yaadav, J Zähringer, Q Wei, A Ozcan, B Lalkens, G P Acuna, P Tinnefeld Addressable Nanoantennas with Cleared Hotspots for Single-Molecule Detection on a Portable Smartphone Microscope Journal Article bioRxiv, pp. 2020.04.09.032037, 0000. Abstract | Links | Tags: Foundry Organic, Molecularly-Functionalized @article{, title = {Addressable Nanoantennas with Cleared Hotspots for Single-Molecule Detection on a Portable Smartphone Microscope}, author = {K Trofymchuk and V Glembockyte and L Grabenhorst and F Steiner and C Vietz and C Close and M Pfeiffer and L Richter and M L Sch\"{u}tte and F Selbach and R Yaadav and J Z\"{a}hringer and Q Wei and A Ozcan and B Lalkens and G P Acuna and P Tinnefeld}, url = {http://biorxiv.org/content/early/2020/04/09/2020.04.09.032037.abstract}, doi = {10.1101/2020.04.09.032037}, journal = {bioRxiv}, pages = {2020.04.09.032037}, abstract = {The advent of highly sensitive photodetectors1,2 and the development of photostabilization strategies3 made detecting the fluorescence of a single molecule a routine task in many labs around the world. However, to this day, this process requires cost-intensive optical instruments due to the truly nanoscopic signal of a single emitter. Simplifying single-molecule detection would enable many exciting applications, e.g. in point-of-care diagnostic settings, where costly equipment would be prohibitive.4 Here, we introduce addressable NanoAntennas with Cleared HOtSpots (NACHOS) that are scaffolded by DNA origami nanostructures and can be specifically tailored for the incorporation of bioassays. Single emitters placed in the NACHOS emit up to 461-fold brighter enabling their detection with a customary smartphone camera and an 8-US-dollar objective lens. To prove the applicability of our system, we built a portable, battery-powered smartphone microscope and successfully carried out an exemplary single-molecule detection assay for DNA specific to antibiotic-resistant Klebsiella pneumonia "on the road “.Competing Interest StatementPT and GPA are inventors on a patent of the described Bottom-up method for fluorescence enhancement in molecular assays, EP1260316.1, 2012, US20130252825 A1.}, keywords = {Foundry Organic, Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } The advent of highly sensitive photodetectors1,2 and the development of photostabilization strategies3 made detecting the fluorescence of a single molecule a routine task in many labs around the world. However, to this day, this process requires cost-intensive optical instruments due to the truly nanoscopic signal of a single emitter. Simplifying single-molecule detection would enable many exciting applications, e.g. in point-of-care diagnostic settings, where costly equipment would be prohibitive.4 Here, we introduce addressable NanoAntennas with Cleared HOtSpots (NACHOS) that are scaffolded by DNA origami nanostructures and can be specifically tailored for the incorporation of bioassays. Single emitters placed in the NACHOS emit up to 461-fold brighter enabling their detection with a customary smartphone camera and an 8-US-dollar objective lens. To prove the applicability of our system, we built a portable, battery-powered smartphone microscope and successfully carried out an exemplary single-molecule detection assay for DNA specific to antibiotic-resistant Klebsiella pneumonia "on the road “.Competing Interest StatementPT and GPA are inventors on a patent of the described Bottom-up method for fluorescence enhancement in molecular assays, EP1260316.1, 2012, US20130252825 A1. |
Publications2020-03-26T14:18:16+01:00