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1.
Synthesis of a Far‐Red Photoactivatable Silicon‐Containing Rhodamine for Super‐Resolution Microscopy 下载免费PDF全文
Jonathan B. Grimm Dr. Teresa Klein Dr. Benjamin G. Kopek Dr. Gleb Shtengel Dr. Harald F. Hess Prof. Dr. Markus Sauer Dr. Luke D. Lavis 《Angewandte Chemie (International ed. in English)》2016,55(5):1723-1727
The rhodamine system is a flexible framework for building small‐molecule fluorescent probes. Changing N‐substitution patterns and replacing the xanthene oxygen with a dimethylsilicon moiety can shift the absorption and fluorescence emission maxima of rhodamine dyes to longer wavelengths. Acylation of the rhodamine nitrogen atoms forces the molecule to adopt a nonfluorescent lactone form, providing a convenient method to make fluorogenic compounds. Herein, we take advantage of all of these structural manipulations and describe a novel photoactivatable fluorophore based on a Si‐containing analogue of Q‐rhodamine. This probe is the first example of a “caged” Si‐rhodamine, exhibits higher photon counts compared to established localization microscopy dyes, and is sufficiently red‐shifted to allow multicolor imaging. The dye is a useful label for super‐resolution imaging and constitutes a new scaffold for far‐red fluorogenic molecules. 相似文献
2.
Nanoscale Distribution of Transforming Growth Factor Receptor on Post‐Golgi Vesicle Revealed by Super‐resolution Microscopy 下载免费PDF全文
Hefei Ruan Dr. Jianqiang Yu Dr. Jinghe Yuan Nan Li Prof. Xiaohong Fang 《化学:亚洲杂志》2016,11(23):3359-3364
Transforming growth factor‐β (TGF‐β) type II receptor (TβRII) plays a critical role in the initiation of TGF‐β signaling pathway; therefore, the study of its synthesis and transport processes is of great important. In this work, we achieved super‐resolution imaging of a new type of TβRII‐containing post‐Golgi vesicle by our home‐built stimulated emission depletion (STED) microscope. We visualized the ring‐shaped structure of these vesicles containing newly synthesized TβRII in the cytoplasm and characterized their size distribution from 300 to 1000 nm. These vesicles could be swollen by chloroquine treatment. Further investigation revealed that TβRII formed clusters on the outer ring of the post‐Golgi vesicles. This study offers new information on the intracellular transportation of TGF‐β receptors for better understanding its signaling process. 相似文献
3.
Chamari S. Wijesooriya Julie A. Peterson Pradeep Shrestha Elizabeth J. Gehrmann Prof. Dr. Arthur H. Winter Prof. Dr. Emily A. Smith 《Angewandte Chemie (International ed. in English)》2018,57(39):12685-12689
The synthesis and application of a photoactivatable boron‐alkylated BODIPY probe for localization‐based super‐resolution microscopy is reported. Photoactivation and excitation of the probe is achieved by a previously unknown boron‐photodealkylation reaction with a single low‐power visible laser and without requiring the addition of reducing agents or oxygen scavengers in the imaging buffer. These features lead to a versatile probe for localization‐based microscopy of biological systems. The probe can be easily linked to nucleophile‐containing molecules to target specific cellular organelles. By attaching paclitaxel to the photoactivatable BODIPY, in vitro and in vivo super‐resolution imaging of microtubules is demonstrated. This is the first example of single‐molecule localization‐based super‐resolution microscopy using a visible‐light‐activated BODIPY compound as a fluorescent probe. 相似文献
4.
Inside Back Cover: Synthesis of a Far‐Red Photoactivatable Silicon‐Containing Rhodamine for Super‐Resolution Microscopy (Angew. Chem. Int. Ed. 5/2016) 下载免费PDF全文
Jonathan B. Grimm Dr. Teresa Klein Dr. Benjamin G. Kopek Dr. Gleb Shtengel Dr. Harald F. Hess Prof. Dr. Markus Sauer Dr. Luke D. Lavis 《Angewandte Chemie (International ed. in English)》2016,55(5):1925-1925
5.
Dr. Ralph Wieneke Anika Raulf Alina Kollmannsperger Prof. Mike Heilemann Prof. Robert Tampé 《Angewandte Chemie (International ed. in English)》2015,54(35):10216-10219
Protein labeling with synthetic fluorescent probes is a key technology in chemical biology and biomedical research. A sensitive and efficient modular labeling approach (SLAP) was developed on the basis of a synthetic small‐molecule recognition unit (Ni‐trisNTA) and the genetically encoded minimal protein His6‐10‐tag. High‐density protein tracing by SLAP was demonstrated. This technique allows super‐resolution fluorescence imaging and fulfills the necessary sampling criteria for single‐molecule localization‐based imaging techniques. It avoids masking by large probes, for example, antibodies, and supplies sensitive, precise, and robust size analysis of protein clusters (nanodomains). 相似文献
6.
Dr. Joaquim Torra Dr. Felipe Viela Dr. Diego Megías Dr. Begoña Sot Prof. Cristina Flors 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(19):e202200026
CRANAD-2 is a fluorogenic curcumin derivative used for near-infrared detection and imaging in vivo of amyloid aggregates, which are involved in neurodegenerative diseases. We explore the performance of CRANAD-2 in two super-resolution imaging techniques, namely stimulated emission depletion (STED) and single-molecule localization microscopy (SMLM), with markedly different fluorophore requirements. By conveniently adapting the concentration of CRANAD-2, which transiently binds to amyloid fibrils, we show that it performs well in both techniques, achieving a resolution in the range of 45–55 nm. Correlation of SMLM with atomic force microscopy (AFM) validates the resolution of fine features in the reconstructed super-resolved image. The good performance and versatility of CRANAD-2 provides a powerful tool for near-infrared nanoscopic imaging of amyloids in vitro and in vivo. 相似文献
7.
A Theoretical Investigation into the Luminescent Properties of d8‐Transition‐Metal Complexes with Tetradentate Schiff Base Ligands 下载免费PDF全文
Dr. Glenna So Ming Tong Dr. Pui Keong Chow Dr. Wai‐Pong To Prof. Wai‐Ming Kwok Prof. Chi‐Ming Che 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(21):6433-6443
A theoretical investigation on the luminescence efficiency of a series of d8 transition‐metal Schiff base complexes was undertaken. The aim was to understand the different photophysics of [M‐salen]n complexes (salen=N,N′‐bis(salicylidene)ethylenediamine; M=Pt, Pd (n=0); Au (n=+1)) in acetonitrile solutions at room temperature: [Pt‐salen] is phosphorescent and [Au‐salen]+ is fluorescent, but [Pd‐salen] is nonemissive. Based on the calculation results, it was proposed that incorporation of electron‐withdrawing groups at the 4‐position of the Schiff base ligand should widen the 3MLCT–3MC gap (MLCT=metal‐to‐ligand charge transfer and MC=metal centered, that is, the dd excited state); thus permitting phosphorescence of the corresponding PdII Schiff base complex. Although it is experimentally proven that [Pd‐salph‐4E] (salph=N,N′‐bis(salicylidene)‐1,2‐phenylenediamine; 4E means an electron‐withdrawing substituent at the 4‐position of the salicylidene) displays triplet emission, its quantum yield is low at room temperature. The corresponding PtII Schiff base complex, [Pt‐salph‐4E], is also much less emissive than the unsubstituted analogue, [Pt‐salph]. Thus, a detailed theoretical analysis of how the substituent and central metal affected the photophysics of [M‐salph‐X] (X is a substituent on the salph ligand, M=Pt or Pd) was performed. Temperature effects were also investigated. The simple energy gap law underestimated the nonradiative decay rates and was insufficient to account for the temperature dependence of the nonradiative decay rates of the complexes studied herein. On the other hand, the present analysis demonstrates that inclusions of low‐frequency modes and the associated frequency shifts are decisive in providing better quantitative estimates of the nonradiative decay rates and the experimentally observed temperature effects. Moreover, spin–orbit coupling, which is often considered only in the context of radiative decay rate, has a significant role in determining the nonradiative rate as well. 相似文献
8.
Chenge Li Alison G. Tebo Marion Thauvin Marie‐Aude Plamont Michel Volovitch Xavier Morin Sophie Vriz Arnaud Gautier 《Angewandte Chemie (International ed. in English)》2020,59(41):17917-17923
Far‐red emitting fluorescent labels are highly desirable for spectral multiplexing and deep tissue imaging. Here, we describe the generation of frFAST (far‐red Fluorescence Activating and absorption Shifting Tag), a 14‐kDa monomeric protein that forms a bright far‐red fluorescent assembly with (4‐hydroxy‐3‐methoxy‐phenyl)allylidene rhodanine (HPAR‐3OM). As HPAR‐3OM is essentially non‐fluorescent in solution and in cells, frFAST can be imaged with high contrast in presence of free HPAR‐3OM, which allowed the rapid and efficient imaging of frFAST fusions in live cells, zebrafish embryo/larvae, and chicken embryos. Beyond enabling the genetic encoding of far‐red fluorescence, frFAST allowed the design of a far‐red chemogenetic reporter of protein–protein interactions, demonstrating its great potential for the design of innovative far‐red emitting biosensors. 相似文献
9.
A Dual‐Color Far‐Red to Near‐Infrared Firefly Luciferin Analogue Designed for Multiparametric Bioluminescence Imaging 下载免费PDF全文
Dr. Amit P. Jathoul Dr. Helen Grounds Prof. James C. Anderson Dr. Martin A. Pule 《Angewandte Chemie (International ed. in English)》2014,53(48):13059-13063
Red‐shifted bioluminescent emitters allow improved in vivo tissue penetration and signal quantification, and have led to the development of beetle luciferin analogues that elicit red‐shifted bioluminescence with firefly luciferase (Fluc). However, unlike natural luciferin, none have been shown to emit different colors with different luciferases. We have synthesized and tested the first dual‐color, far‐red to near‐infrared (nIR) emitting analogue of beetle luciferin, which, akin to natural luciferin, exhibits pH dependent fluorescence spectra and emits bioluminescence of different colors with different engineered Fluc enzymes. Our analogue produces different far‐red to nIR emission maxima up to λmax=706 nm with different Fluc mutants. This emission is the most red‐shifted bioluminescence reported without using a resonance energy transfer acceptor. This improvement should allow tissues to be more effectively probed using multiparametric deep‐tissue bioluminescence imaging. 相似文献
10.
Babak Karimi Prof. Dr. Dawood Elhamifar Dr. James H. Clark Prof. Dr. Andrew J. Hunt Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(27):8047-8053
The preparation of a novel palladium‐supported periodic mesoporous organosilica based on alkylimidazolium ionic liquid (Pd@PMO‐IL) in which imidazoilium ionic liquid is uniformly distributed in the silica mesoporous framework is described. Both Pd@PMO‐IL and the parent PMO‐IL were characterized by N2‐adsorption–desorption, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), TEM, and solid‐state NMR spectroscopy. We have demonstrated that Pd@PMO‐IL is an efficient and reusable catalyst for the Suzuki–Miyaura coupling reaction of various types of iodo‐, bromo‐, and even deactivated aryl chlorides in water. It was also found that although the PMO‐IL nanostructure acts as reservoir for soluble Pd species, it can also operate as a nanoscaffold to recapture the Pd nanoparticles into the mesochannels thus preventing extensive agglomeration of Pd. This observation might be attributed to the isolated ionic liquid units that effectively control the reaction mechanism by preventing Pd agglomeration and releasing and recapturing Pd nanoparticles during the reaction process. The catalyst can be recovered and reused for at least four reaction cycles without significant loss of activity. 相似文献
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Intermolecular Electronic Coupling of Organic Units for Efficient Persistent Room‐Temperature Phosphorescence 下载免费PDF全文
Dr. Zhiyong Yang Dr. Zhu Mao Dr. Xuepeng Zhang Dr. Depei Ou Dr. Yingxiao Mu Prof. Yi Zhang Prof. Cunyuan Zhao Prof. Siwei Liu Prof. Zhenguo Chi Prof. Jiarui Xu Dr. Yuan‐Chun Wu Dr. Po‐Yen Lu Dr. Alan Lien Prof. Martin R. Bryce 《Angewandte Chemie (International ed. in English)》2016,55(6):2181-2185
Although persistent room‐temperature phosphorescence (RTP) emission has been observed for a few pure crystalline organic molecules, there is no consistent mechanism and no universal design strategy for organic persistent RTP (pRTP) materials. A new mechanism for pRTP is presented, based on combining the advantages of different excited‐state configurations in coupled intermolecular units, which may be applicable to a wide range of organic molecules. By following this mechanism, we have developed a successful design strategy to obtain bright pRTP by utilizing a heavy halogen atom to further increase the intersystem crossing rate of the coupled units. RTP with a remarkably long lifetime of 0.28 s and a very high quantum efficiency of 5 % was thus obtained under ambient conditions. This strategy represents an important step in the understanding of organic pRTP emission. 相似文献
14.
Prof. Dr. Kasper P. Kepp 《Chemphyschem》2013,14(15):3551-3558
This paper reports the computed O2 binding to heme, which for the first time explains experimental enthalpies for this process of central importance to bioinorganic chemistry. All four spin states along the relaxed Fe? O2‐binding curves were optimized using the full heme system with dispersion, thermodynamic, and scalar‐relativistic corrections, applying several density functionals. When including all these physical terms, the experimental enthalpy of O2 binding (?59 kJ mol?1) is closely reproduced by TPSSh‐D3 (?66 kJ mol?1). Dispersion changes the potential energy surfaces and leads to the correct electronic singlet and heptet states for bound and dissociated O2. The experimental activation enthalpy of dissociation (~82 kJ mol?1) was also accurately computed (~75 kJ mol?1) with an actual barrier height of ~60 kJ mol?1 plus a vibrational component of ~10 and ~5 kJ mol?1 due to the spin‐forbidden nature of the process, explaining the experimentally observed difference of ~20 kJ mol?1 in enthalpies of binding and activation. Most importantly, the work shows how the nearly degenerate singlet and triplet states increase crossover probability up to ~0.5 and accelerate binding by ~100 times, explaining why the spin‐forbidden binding of O2 to heme, so fundamental to higher life forms, is fast and reversible. 相似文献
15.
Liangliang Liang Dr. Xiaoji Xie Dr. Daniel Teh Boon Loong Prof. Angelo Homayoun All Prof. Ling Huang Prof. Xiaogang Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(31):10801-10807
A crystal design strategy is described that generates hexagonal‐phased NaYF4:Nd/Yb@NaYF4:Yb/Tm luminescent nanocrystals with the ability to emit light at 803 nm when illuminated at 745 nm. This is accomplished by taking advantage of the large absorption cross‐section of Nd3+ between 720 and 760 nm plus efficient spatial energy transfer and migration through Nd3+→Yb3+→Yb3+→Tm3+. Mechanistic investigations suggest that a cascaded two‐photon energy transfer upconversion process underlies the emission mechanism. This protocol enables deep‐tissue imaging to be achieved while mitigating the attenuation effect associated with the visible emission and the overheating constraint imposed by conventional 980 nm excitation. 相似文献
16.
Feng Chen Dr. Wenbo Bu Prof. Yu Chen Dr. Yuchi Fan Dr. Qianjun He Dr. Min Zhu Dr. Xiaohang Liu Dr. Liangping Zhou Prof. Shengjian Zhang Dr. Weijun Peng Prof. Jianlin Shi Prof. 《化学:亚洲杂志》2009,4(12):1809-1816
Oleic acid stabilized superparamagnetic iron oxide nanoparticles (SPION) were selected as the cores for fabrication of sub‐50‐nm monodisperse single‐loaded SPION@SiO2 core–shell nanostructures. Parameters that influence the formation of SPION@SiO2 in the water‐in‐oil reverse microemulsion system have been systematically investigated. The sufficiently high concentration of well‐dispersed SPION, together with an appropriately low injection rate of tetraethoxysilane, were found to be the keys to efficiently prevent the homogeneous nucleation of silica and obtain a high‐quality single‐loaded core–shell nanocomposite. A more detailed mechanism for incorporating oleic acid capped inorganic functional nanoparticles into silica is proposed on the basis of previous reports and our new experimental results. Finally, the as‐synthesized SPION@SiO2 nanospheres are exploited as an MRI‐enhanced contrast agent, and their contrast effect in solution is tested by using a clinical MRI instrument. 相似文献
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Miao‐Ken Hung Kuen‐Wei Tsai Sunil Sharma Jun‐Yi Wu Show‐An Chen 《Angewandte Chemie (International ed. in English)》2019,58(33):11317-11323
We propose the novel σ–π conjugated polymer poly(biphenyl germanium) grafted with two electron‐donating acridan moieties on the Ge atom for use as the host material in a polymer light‐emitting diode (PLED) with the sky‐blue‐emitting thermally activated delayed fluorescence (TADF) material DMAC‐TRZ as the guest. Its high triplet energy (ET) of 2.86 eV is significantly higher than those of conventional π–π conjugated polymers (ET=2.65 eV as the limit) and this guest emitter (ET=2.77 eV). The TADF emitter emits bluer emission than in other host materials owing to the low orientation polarizability of the germanium‐based polymer host. The Ge atom also provides an external heavy‐atom effect, which increases the rate of reverse intersystem crossing in this TADF guest, so that more triplet excitons are harvested for light emission. The sky‐blue TADF electroluminescence with this host/guest pair gave a record‐high external quantum efficiency of 24.1 % at maximum and 22.8 % at 500 cd m?2. 相似文献
19.
Feng Chen Shengjian Zhang Prof. Wenbo Bu Yu Chen Qingfeng Xiao Jianan Liu Huaiyong Xing Dr. Liangping Zhou Prof. Weijun Peng Prof. Jianlin Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(23):7082-7090
Upconverting nanoparticles (UCNPs) with fascinating properties hold great potential as nanotransducers for solving the problems that traditional photodynamic therapy (PDT) has been facing. In this report, by using well‐selected bifunctional gadolinium (Gd)‐ion‐doped UCNPs and water‐soluble methylene blue (MB) combined with the water‐in‐oil reverse microemulsion technique, we have succeeded in developing a new kind of UCNP/MB‐based PDT drug, NaYF4:Er/Yb/Gd@SiO2(MB), with a particle diameter less than 50 nm. Great efforts have been made to investigate the drug‐formation mechanism and provide detailed physical and photochemical characterizations and the potential structure optimization of the as‐designed PDT drug. We envision that such a PDT drug will become a potential theranostic nanomedicine for future near‐infrared laser‐triggered photodynamic therapy and simultaneous magnetic/optical bimodal imaging. 相似文献
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Sandeep Verma Prasenjit Kar Amitava Das Dr. Dipak K. Palit Dr. Hirendra N. Ghosh Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(2):611-619
We have synthesized ruthenium(II)– and osmium(II)–polypyridyl complexes ([M(bpy)2 L ]2+, in which M=OsII or RuII, bpy=2,2′‐bipyridyl, and L =4‐(2,2′‐bipyridinyl‐4‐yl)benzene‐1,2‐diol) and studied the interfacial electron‐transfer process on a TiO2 nanoparticle surface using femtosecond transient‐absorption spectroscopy. Ruthenium(II)‐ and osmium(II)‐based dyes have a similar molecular structure; nevertheless, we have observed quite different interfacial electron‐transfer dynamics (both forward and backward). In the case of the RuII/TiO2 system, single‐exponential electron injection takes place from photoexcited nonthermalized metal‐to‐ligand charge transfer (MLCT) states. However, in the case of the OsII/TiO2 system, electron injection takes place biexponentially from both nonthermalized and thermalized MLCT states (mainly 3MLCT states). Larger spin–orbit coupling for the heavier transition‐metal osmium, relative to that of ruthenium, accounts for the more efficient population of the 3MLCT states in the OsII‐based dye during the electron‐injection process that yields biexponential dynamics. Our results tend to suggest that appropriately designed OsII–polypyridyl dye can be a better sensitizer molecule relative to its RuII analogue not only due to much broader absorption in the visible region of the solar‐emission spectrum, but also on account of slower charge recombination. 相似文献