共查询到20条相似文献,搜索用时 31 毫秒
1.
Elizabeth Baggaley Martin R. Gill Nicola H. Green David Turton Igor V. Sazanovich Stanley W. Botchway Carl Smythe John W. Haycock Julia A. Weinstein Jim A. Thomas 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(13):3435-3439
The first transition‐metal complex‐based two‐photon absorbing luminescence lifetime probes for cellular DNA are presented. This allows cell imaging of DNA free from endogenous fluorophores and potentially facilitates deep tissue imaging. In this initial study, ruthenium(II) luminophores are used as phosphorescent lifetime imaging microscopy (PLIM) probes for nuclear DNA in both live and fixed cells. The DNA‐bound probes display characteristic emission lifetimes of more than 160 ns, while shorter‐lived cytoplasmic emission is also observed. These timescales are orders of magnitude longer than conventional FLIM, leading to previously unattainable levels of sensitivity, and autofluorescence‐free imaging. 相似文献
2.
Xuping Li Gleb Baryshnikov Longjiang Ding Xiaoyan Bao Xin Li Jianjun Lu Miaoqing Liu Shen Shen Mengkai Luo Man Zhang Hans gren Xudong Wang Liangliang Zhu 《Angewandte Chemie (International ed. in English)》2020,59(19):7548-7554
Developing luminescent probes with long lifetime and high emission efficiency is essential for time‐resolved imaging. However, the practical applications usually suffer from emission quenching of traditional luminogens in aggregated states, or from weak emission of aggregation‐induced emission type luminogens in monomeric states. Herein, we overcome this dilemma by a rigid‐and‐flexible alternation design in donor–acceptor–donor skeletons, to achieve a thermally activated delayed fluorescence luminogen with high emission efficiency both in the monomeric state (quantum yield up to 35.3 %) and in the aggregated state (quantum yield up to 30.8 %). Such a dual‐phase strong and long‐lived emission allows a time‐resolved luminescence imaging, with an efficiency independent of probe pretreatment and probe concentration. The findings open opportunities for developing luminescent probes with a usage in larger temporal and spatial scales. 相似文献
3.
Combined Two‐Photon Excitation and d→f Energy Transfer in a Water‐Soluble IrIII/EuIII Dyad: Two Luminescence Components from One Molecule for Cellular Imaging
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Elizabeth Baggaley Prof. Deng‐Ke Cao Dr. Daniel Sykes Prof. Stanley W. Botchway Dr. Julia A. Weinstein Prof. Michael D. Ward 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(29):8898-8903
The first example of cell imaging using two independent emission components from a dinuclear d/f complex is reported. A water‐stable, cell‐permeable IrIII/EuIII dyad undergoes partial Ir→Eu energy transfer following two‐photon excitation of the Ir unit at 780 nm. Excitation in the near‐IR region generated simultaneously green Ir‐based emission and red Eu‐based emission from the same probe. The orders‐of‐magnitude difference in their timescales (Ir ca. μs; Eu ca. 0.5 ms) allowed them to be identified by time‐gated detection. Phosphorescence lifetime imaging microscopy (PLIM) allowed the lifetime of the Ir‐based emission to be measured in different parts of the cell. At the same time, the cells are simultaneously imaged by using the Eu‐based emission component at longer timescales. This new approach to cellular imaging by using dual d/f emitters should therefore enable autofluorescence‐free sensing of two different analytes, independently, simultaneously and in the same regions of a cell. 相似文献
4.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(47):15124-15128
Designing probes for real‐time imaging of dynamic processes in living cells is a continuous challenge. Herein, a novel near‐infrared (NIR) photoluminescence probe having a long lifetime was exploited for photoluminescence lifetime imaging (PLIM) using an iridium‐alkyne complex. This probe offers the benefits of deep‐red to NIR emission, a long Stokes shift, excellent cell penetration, low cytotoxicity, and good resistance to photobleaching. This example is the first PLIM probe applicable to the click reaction of copper(I)‐catalyzed azide–alkyne cycloaddition (CuAAC) with remarkable lifetime shifts of 414 ns, before and after click reaction. The approach fully eliminates the background interference and distinguishes the reacted probes from the unreacted probes, thus enabling the wash‐free imaging of the newly synthesized proteins within single living cells. Based on the unique properties of the iridium complexes, it is anticipated to have applications for imaging other processes within living cells. 相似文献
5.
Mapping Live Cell Viscosity with an Aggregation‐Induced Emission Fluorogen by Means of Two‐Photon Fluorescence Lifetime Imaging
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Sijie Chen Dr. Yuning Hong Dr. Yan Zeng Qiqi Sun Dr. Yang Liu Engui Zhao Gongxun Bai Prof. Jianan Qu Prof. Jianhua Hao Prof. Ben Zhong Tang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(11):4315-4320
Intracellular viscosity is a crucial parameter that indicates the functioning of cells. In this work, we demonstrate the utility of TPE‐Cy, a cell‐permeable dye with aggregation‐induced emission (AIE) property, in mapping the viscosity inside live cells. Owing to the AIE characteristics, both the fluorescence intensity and lifetime of this dye are increased along with an increase in viscosity. Fluorescence lifetime imaging of live cells stained with TPE‐Cy reveals that the lifetime in lipid droplets is much shorter than that from the general cytoplasmic region. The loose packing of the lipids in a lipid droplet results in low viscosity and thus shorter lifetime of TPE‐Cy in this region. It demonstrates that the AIE dye could provide good resolution in intracellular viscosity sensing. This is also the first work in which AIE molecules are applied in fluorescence lifetime imaging and intracellular viscosity sensing. 相似文献
6.
Bioorthogonal Turn‐On Probe Based on Aggregation‐Induced Emission Characteristics for Cancer Cell Imaging and Ablation
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Youyong Yuan Shidang Xu Dr. Xiamin Cheng Xiaolei Cai Prof. Bin Liu 《Angewandte Chemie (International ed. in English)》2016,55(22):6457-6461
Bioorthogonal turn‐on probes have been widely utilized in visualizing various biological processes. Most of the currently available bioorthogonal turn‐on probes are blue or green emissive fluorophores with azide or tetrazine as functional groups. Herein, we present an alternative strategy of designing bioorthogonal turn‐on probes based on red‐emissive fluorogens with aggregation‐induced emission characteristics (AIEgens). The probe is water soluble and non‐fluorescent due to the dissipation of energy through free molecular motion of the AIEgen, but the fluorescence is immediately turned on upon click reaction with azide‐functionalized glycans on cancer cell surface. The fluorescence turn‐on is ascribed to the restriction of molecular motion of AIEgen, which populates the radiative decay channel. Moreover, the AIEgen can generate reactive oxygen species (ROS) upon visible light (λ=400–700 nm) irradiation, demonstrating its dual role as an imaging and phototherapeutic agent. 相似文献
7.
Applications of “Hot” and “Cold” Bis(thiosemicarbazonato) Metal Complexes in Multimodal Imaging
下载免费PDF全文
![点击此处可从《Chemical record (New York, N.Y.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Fernando Cortezon‐Tamarit Sophia Sarpaki David G. Calatayud Vincenzo Mirabello Sofia I. Pascu 《Chemical record (New York, N.Y.)》2016,16(3):1380-1397
The applications of coordination chemistry to molecular imaging has become a matter of intense research over the past 10 years. In particular, the applications of bis(thiosemicarbazonato) metal complexes in molecular imaging have mainly been focused on compounds with aliphatic backbones due to the in vivo imaging success of hypoxic tumors with PET (positron emission tomography) using 64CuATSM [copper (diacetyl‐bis(N4‐methylthiosemicarbazone))]. This compound entered clinical trials in the US and the UK during the first decade of the 21st century for imaging hypoxia in head and neck tumors. The replacement of the ligand backbone to aromatic groups, coupled with the exocyclic N's functionalization during the synthesis of bis(thiosemicarbazones) opens the possibility to use the corresponding metal complexes as multimodal imaging agents of use, both in vitro for optical detection, and in vivo when radiolabeled with several different metallic species. The greater kinetic stability of acenaphthenequinone bis(thiosemicarbazonato) metal complexes, with respect to that of the corresponding aliphatic ATSM complexes, allows the stabilization of a number of imaging probes, with special interest in “cold” and “hot” Cu(II) and Ga(III) derivatives for PET applications and 111In(III) derivatives for SPECT (single‐photon emission computed tomography) applications, whilst Zn(II) derivatives display optical imaging properties in cells, with enhanced fluorescence emission and lifetime with respect to the free ligands. Preliminary studies have shown that gallium‐based acenaphthenequinone bis(thiosemicarbazonato) complexes are also hypoxia selective in vitro, thus increasing the interest in them as new generation imaging agents for in vitro and in vivo applications. 相似文献
8.
Red‐ and Green‐Emitting Iridium(III) Complexes for a Dual Barometric and Temperature‐Sensitive Paint
Lorenz H. Fischer Matthias I. J. Stich Otto S. Wolfbeis Prof. Nan Tian Elisabeth Holder Prof. Michael Schäferling Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(41):10857-10863
A new dual luminescent sensitive paint for barometric pressure and temperature (T) is presented. The green‐emitting iridium(III) complex [Ir(ppy)2(carbac)] (ppy=2‐phenylpyridine; carbac=1‐(9H‐carbazol‐9‐yl)‐5,5‐dimethylhexane‐2,4‐dione) was applied as a novel probe for T along with the red‐emitting complex [Ir(btpy)3], (btpy=2‐(benzo[b]thiophene‐2‐yl)pyridine) which functions as a barometric (in fact oxygen‐sensitive) probe. Both iridium complexes were dissolved in different polymer materials to achieve optimal responses. The probe [Ir(ppy)2(carbac)] was dispersed in gas‐blocking poly(acrylonitrile) microparticles in order to suppress any quenching of its luminescence by oxygen. The barometric probe [Ir(btpy)3], in turn, was incorporated in a cellulose acetate butyrate film which exhibits good permeability for oxygen. The effects of temperature on the response of the oxygen probe can be corrected by simultaneous optical determination of T, as the poly(acrylonitrile) microparticles containing the temperature indicator are incorporated into the film. The phosphorescent signals of the probes for T and barometric pressure, respectively, can be separated by optical filters due to the ≈75 nm difference in their emission maxima. The dual sensor is applicable to luminescence lifetime imaging of T and barometric pressure. It is the first luminescent dual sensor material for barometric pressure/T based exclusively on the use of IrIII complexes in combination with luminescence lifetime imaging. 相似文献
9.
An Easily Accessible Ionic Aggregation‐Induced Emission Luminogen with Hydrogen‐Bonding‐Switchable Emission and Wash‐Free Imaging Ability
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Yuncong Chen Dr. Weijie Zhang Dr. Zheng Zhao Dr. Yuanjing Cai Junyi Gong Dr. Ryan T. K. Kwok Dr. Jacky W. Y. Lam Dr. Herman H. Y. Sung Prof. Ian D. Williams Prof. Ben Zhong Tang 《Angewandte Chemie (International ed. in English)》2018,57(18):5011-5015
Ionic fluorophores are powerful tools for the study of environmental science and bio‐imaging. However, traditional ionic dyes usually require long synthetic steps and suffer from a quenching effect caused by aggregation. A water‐soluble ionic aggregation‐induced emission luminogen called DBTA is presented, which is readily accessed by a one‐step reaction. The switchable emission manipulated by hydrogen bonding provided solid evidence for the restriction of intramolecular motions as the mechanism of aggregation‐induced emission. DBTA can not only differentiate solvents with different H‐bond donor acidities but also capable of wash‐free imaging in living HeLa cells and fish larva. 相似文献
10.
Zhe Zhang Xiaofeng Fang Zhihe Liu Haichao Liu Dandan Chen Shuqing He Jie Zheng Bing Yang Weiping Qin Xuanjun Zhang Changfeng Wu 《Angewandte Chemie (International ed. in English)》2020,59(9):3691-3698
Fluorescence probes in the NIR‐IIa region show drastically improved imaging owing to the reduced photon scattering and autofluorescence in biological tissues. Now, NIR‐IIa polymer dots (Pdots) are developed with a dual fluorescence enhancement mechanism. First, the aggregation induced emission of phenothiazine was used to reduce the nonradiative decay pathways of the polymers in condensed states. Second, fluorescence quenching was minimized by different levels of steric hindrance to further boost the fluorescence. The resulting Pdots displayed a fluorescence QY of ca. 1.7 % in aqueous solution, suggesting an enhancement of ca. 21 times in comparison with the original polymer in tetrahydrofuran (THF) solution. Small‐animal imaging by using the NIR‐IIa Pdots exhibited a remarkable improvement in penetration depth and signal to background ratio, as confirmed by through‐skull and through‐scalp fluorescent imaging of the cerebral vasculature of live mice. 相似文献
11.
Mengkai Luo Xuping Li Longjiang Ding Gleb Baryshnikov Shen Shen Mingjie Zhu Lulu Zhou Man Zhang Jianjun Lu Hans gren Xu‐dong Wang Liangliang Zhu 《Angewandte Chemie (International ed. in English)》2020,59(39):17018-17025
The fact that the lifetime of photoluminescence is often difficult to access because of the weakness of the emission signals, seriously limits the possibility to gain local bioimaging information in time‐resolved luminescence probing. We aim to provide a solution to this problem by creating a general photophysical strategy based on the use of molecular probes designed for single‐luminophore dual thermally activated delayed fluorescence (TADF). The structural and conformational design makes the dual TADF strong in both diluted solution and in an aggregated state, thereby reducing sensitivity to oxygen quenching and enabling a unique dual‐channel time‐resolved imaging capability. As the two TADF signals show mutual complementarity during probing, a dual‐channel means that lifetime mapping is established to reduce the time‐resolved imaging distortion by 30–40 %. Consequently, the leading intracellular local imaging information is serialized and integrated, which allows comparison to any single time‐resolved signal, and leads to a significant improvement of the probing capacity. 相似文献
12.
Catalytic Molecular Imaging of MicroRNA in Living Cells by DNA‐Programmed Nanoparticle Disassembly
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Xuewen He Tao Zeng Zhi Li Ganglin Wang Prof. Nan Ma 《Angewandte Chemie (International ed. in English)》2016,55(9):3073-3076
Molecular imaging is an essential tool for disease diagnostics and treatment. Direct imaging of low‐abundance nucleic acids in living cells remains challenging because of the relatively low sensitivity and insufficient signal‐to‐background ratio of conventional molecular imaging probes. Herein, we report a class of DNA‐templated gold nanoparticle (GNP)–quantum dot (QD) assembly‐based probes for catalytic imaging of cancer‐related microRNAs (miRNA) in living cells with signal amplification capacity. We show that a single miRNA molecule could catalyze the disassembly of multiple QDs with the GNP through a DNA‐programmed thermodynamically driven entropy gain process, yielding significantly amplified QD photoluminescence (PL) for miRNA imaging. By combining the robust PL of QDs with the catalytic amplification strategy, three orders of magnitude improvement in detection sensitivity is achieved in comparison with non‐catalytic imaging probe, which enables facile and accurate differentiation between cancer cells and normal cells by miRNA imaging in living cells. 相似文献
13.
Jie Wang Zizhao Huang Xiang Ma He Tian 《Angewandte Chemie (International ed. in English)》2020,59(25):9928-9933
Solid‐state materials with efficient room‐temperature phosphorescence (RTP) emissions have found widespread applications in materials science, while liquid or solution‐phase pure organic RTP emission systems has been rarely reported, because of the nonradiative decay and quenchers from the liquid medium. Reported here is the first example of visible‐light‐excited pure organic RTP in aqueous solution by using a supramolecular host‐guest assembly strategy. The unique cucurbit[8]uril‐mediated quaternary stacking structure allows tunable photoluminescence and visible‐light excitation, enabling the fabrication of multicolor hydrogels and cell imaging. The present assembly‐induced emission approach, as a proof of concept, contributes to the construction of novel metal‐free RTP systems with tunable photoluminescence in aqueous solution, providing broad opportunities for further applications in biological imaging, detection, optical sensors, and so forth. 相似文献
14.
Dr. Shuai Chen Xin Hai Chang Xia Prof. Dr. Xu‐Wei Chen Prof. Dr. Jian‐Hua Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(47):15918-15923
We report the first pyrrole‐ring surface‐functionalized graphene quantum dots (p‐GQDs) prepared by a two‐step hydrothermal approach under microwave irradiation in an ammonia medium. The most distinct feature of the functionalized GQDs is that both the excitation and emission wavelengths fall into the visible‐light region. The p‐GQDs are excited by visible light at λex 490 nm (2.53 eV) to emit excitation‐independent photoluminescence at a maximum wavelength of λem 550 nm. This is thus far the longest emission wavelength reported for GQDs. Stable photoluminescence is achieved at pH 4–10 with an ionic strength of 1.2 mol L?1 KCl. These features make the p‐GQDs excellent probes for bio‐imaging and bio‐labeling, which is demonstrated by imaging live HeLa cells. 相似文献
15.
Jinqiao Dong Yutong Pan Heng Wang Kuiwei Yang Lingmei Liu Zhiwei Qiao Yi Di Yuan Shing Bo Peh Jian Zhang Leilei Shi Hong Liang Yu Han Xiaopeng Li Jianwen Jiang Bin Liu Dan Zhao 《Angewandte Chemie (International ed. in English)》2020,59(25):10151-10159
The self‐assembly of highly stable zirconium(IV)‐based coordination cages with aggregation induced emission (AIE) molecular rotors for in vitro bio‐imaging is reported. The two coordination cages, NUS‐100 and NUS‐101, are assembled from the highly stable trinuclear zirconium vertices and two flexible carboxyl‐decorated tetraphenylethylene (TPE) spacers. Extensive experimental and theoretical results show that the emissive intensity of the coordination cages can be controlled by restricting the dynamics of AIE‐active molecular rotors though multiple external stimuli. Because the two coordination cages have excellent chemical stability in aqueous solutions (pH stability: 2–10) and impressive AIE characteristics contributed by the molecular rotors, they can be employed as novel biological fluorescent probes for in vitro live‐cell imaging. 相似文献
16.
Efficient Discrimination of Single Nucleotide Polymorphisms (SNPs) Using Oligonucleotides Modified with C5‐Pyrene‐Functionalized DNA and Flanking Locked Nucleic Acid (LNA) Monomers
下载免费PDF全文
![点击此处可从《化学:亚洲杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Oligodeoxyribonucleotides modified with 5‐[3‐(1‐pyrenecarboxamido)propynyl]‐2′‐deoxyuridine monomer X and proximal LNA monomers display higher affinity for complementary DNA, more pronounced increases in fluorescence emission upon DNA binding, and improved discrimination of SNPs at non‐stringent conditions, relative to the corresponding LNA‐free probes across a range of sequence contexts. The results reported herein suggest that the introduction of LNA monomers influences the position of nearby fluorophores via indirect conformational restriction, a characteristic that can be utilized to develop optimized fluorophore‐labeled probes for SNP‐discrimination studies. 相似文献
17.
Conferring Phosphorogenic Properties on Iridium(III)‐Based Bioorthogonal Probes through Modification with a Nitrone Unit
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Lawrence Cho‐Cheung Lee Jonathan Chun‐Wai Lau Dr. Hua‐Wei Liu Prof. Kenneth Kam‐Wing Lo 《Angewandte Chemie (International ed. in English)》2016,55(3):1046-1049
The use of bioorthogonal probes that display fluorogenic or phosphorogenic properties is advantageous to the labeling and imaging of biomolecules in live cells and organisms. Herein we present the design of three iridium(III) complexes containing a nitrone moiety as novel phosphorogenic bioorthogonal probes. These probes were non‐emissive owing to isomerization of the C=N group but showed significant emission enhancement upon cycloaddition reaction with strained cyclooctynes. Interestingly, the connection of the nitrone ligand to the cationic iridium(III) center led to accelerated reaction kinetics. These nitrone complexes were also identified as phosphorogenic bioorthogonal labels and imaging reagents for cyclooctyne‐modified proteins. These findings contribute to the development of phosphorogenic bioorthogonal probes and imaging reagents. 相似文献
18.
Hooi Ling Kee James R. Diers Marcin Ptaszek Chinnasamy Muthiah Dazhong Fan Jonathan S. Lindsey David F. Bocian Dewey Holten 《Photochemistry and photobiology》2009,85(4):909-920
The photophysical properties of two energy‐transfer dyads that are potential candidates for near‐infrared (NIR) imaging probes are investigated as a function of solvent polarity. The dyads ( FbC‐FbB and ZnC‐FbB ) contain either a free base (Fb) or zinc (Zn) chlorin (C) as the energy donor and a free base bacteriochlorin (B) as the energy acceptor. The dyads were studied in toluene, chlorobenzene, 1,2‐dichlorobenzene, acetone, acetonitrile and dimethylsulfoxide (DMSO). In both dyads, energy transfer from the chlorin to bacteriochlorin occurs with a rate constant of ~(5–10 ps)?1 and a yield of >99% in nonpolar and polar media. In toluene, the fluorescence yields (Φ f = 0.19) and singlet excited‐state lifetimes (τ~5.5 ns) are comparable to those of the benchmark bacteriochlorin. The fluorescence yield and excited‐state lifetime decrease as the solvent polarity increases, with quenching by intramolecular electron (or hole) transfer being greater for FbC‐FbB than for ZnC‐FbB in a given solvent. For example, the Φ f and τ values for FbC‐FbB in acetone are 0.055 and 1.5 ns and in DMSO are 0.019 and 0.28 ns, whereas those for ZnC‐FbB in acetone are 0.12 and 4.5 ns and in DMSO are 0.072 and 2.4 ns. The difference in fluorescence properties of the two dyads in a given polar solvent is due to the relative energies of the lowest energy charge‐transfer states, as assessed by ground‐state redox potentials and supported by molecular‐orbital energies derived from density functional theory calculations. Controlling the extent of excited‐state quenching in polar media will allow the favorable photophysical properties of the chlorin–bacteriochlorin dyads to be exploited in vivo. These properties include very large Stokes shifts (85 nm for FbC‐FbB , 110 nm for ZnC‐FbB ) between the red‐region absorption of the chlorin and the NIR fluorescence of the bacteriochlorin (λ f = 760 nm), long bacteriochlorin excited‐state lifetime (~5.5 ns), and narrow (≤20 nm) absorption and fluorescence bands. The latter will facilitate selective excitation/detection and multiprobe applications using both intensity‐ and lifetime‐imaging techniques. 相似文献
19.
Nina Melnychuk Sylvie Egloff Anne Runser Andreas Reisch Andrey S. Klymchenko 《Angewandte Chemie (International ed. in English)》2020,59(17):6811-6818
Controlling the emission of bright luminescent nanoparticles by a single molecular recognition event remains a challenge in the design of ultrasensitive probes for biomolecules. Herein, we developed 20‐nm light‐harvesting nanoantenna particles, built of a tailor‐made hydrophobic charged polymer poly(ethyl methacrylate‐co‐methacrylic acid), encapsulating circa 1000 strongly coupled and highly emissive rhodamine dyes with their bulky counterion. Being 87‐fold brighter than quantum dots QDots 605 in single‐particle microscopy (with 550‐nm excitation), these DNA‐functionalized nanoparticles exhibit over 50 % total FRET efficiency to a single hybridized FRET acceptor, a highly photostable dye (ATTO665), leading to circa 250‐fold signal amplification. The obtained FRET nanoprobes enable single‐molecule detection of short DNA and RNA sequences, encoding a cancer marker (survivin), and imaging single hybridization events by an epi‐fluorescence microscope with ultralow excitation irradiance close to that of ambient sunlight. 相似文献
20.
Serum Albumin Binding Inhibits Nuclear Uptake of Luminescent Metal‐Complex‐Based DNA Imaging Probes
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Ashley Wragg Dr. Martin R. Gill Luke McKenzie Caroline Glover Rachel Mowll Dr. Julia A. Weinstein Dr. Xiaodi Su Prof. Carl Smythe Prof. Jim A. Thomas 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(33):11865-11871
The DNA binding and cellular localization properties of a new luminescent heterobimetallic IrIIIRuII tetrapyridophenazine complex are reported. Surprisingly, in standard cell media, in which its tetracationic, isostructural RuIIRuII analogue is localized in the nucleus, the new tricationic complex is poorly taken up by live cells and demonstrates no nuclear staining. Consequent cell‐free studies reveal that the IrIIIRuII complex binds bovine serum albumin, BSA, in Sudlow’s Site I with a similar increase in emission and binding affinity to that observed with DNA. Contrastingly, in serum‐free conditions the complex is rapidly internalized by live cells, where it localizes in cell nuclei and functions as a DNA imaging agent. The absence of serum proteins also greatly alters the cytotoxicity of the complex, where high levels of oncosis/necrosis are observed due to this enhanced uptake. This suggests that simply increasing the lipophilicity of a DNA imaging probe to enhance cellular uptake can be counterproductive as, due to increased binding to serum albumin protein, this strategy can actually disrupt nuclear targeting. 相似文献