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1.
Fluorescent nanoparticles (NPs) based on luminogens with aggregation‐induced emission characteristic (AIEgens), namely AIE dots, have received wide attention because of their antiquenching attitude in emission and reactive oxygen species (ROS) generation when aggregated. However, few reports are available on how to control and optimize their fluorescence and ROS generation ability. Herein, it is reported that enhancing the intraparticle confined microenvironment is an effective approach to advanced AIE dots, permitting boosted cancer phototheranostics in vivo. Formulation of a “rotor‐rich” and inherently charged near‐infrared (NIR) AIEgen with 1,2‐distearoyl‐sn‐glycero‐3‐phosphoethanolamine‐N‐[methoxy(polyethylene glycol)‐2000] and corannulene‐decorated PEG affords DSPE‐AIE dots and Cor‐AIE dots, respectively. Compared to DSPE‐AIE dots, Cor‐AIE dots show 4.0‐fold amplified fluorescence quantum yield and 5.4‐fold enhanced ROS production, because corannulene provides intraparticle rigidity and strong interactions with the AIEgen to restrict the intramolecular rotation of AIEgen to strongly suppress the nonradiative decay and significantly facilitate the fluorescence pathway and intersystem crossing. Thus, it tremendously promotes phototheranostic efficacies in terms of NIR image‐guided cancer surgery and photodynamic therapy using a peritoneal carcinomatosis‐bearing mouse model. Collectively, it not only provides a novel strategy to advanced AIE dots for cancer phototheranostics, but also brings new insights into the design of superior fluorescent NPs for biomedical applications.  相似文献   

2.
Fluorescence‐imaging‐guided photodynamic therapy has emerged as a promising protocol for cancer theranostics. However, facile preparation of such a theranostic material for simultaneously achieving bright emission with long wavelength, high‐performance reactive oxygen species (ROS) generation, and good targeting‐specificity of cancer cells, is highly desirable but remains challenging. In this study, a novel type of far‐red/near‐infrared‐emissive fluorescent molecules with aggregation‐induced emission (AIE) characteristics is synthesized through a few steps reaction. These AIE luminogens (AIEgens) possess simple structures, excellent photostabilities, large Stokes shifts, bright emission, and good biocompatibilities. Meanwhile, their ROS generation is extremely efficient with up to 90.7% of ROS quantum yield, which is far superior to that of some popularly used photosensitizers. Importantly, these AIEgens are able to selectively target and ablate cancer cells over normal cells without the aid of any extra targeting ligands. Rather than using laser light, one of the presented AIEgens (MeTTPy) shows a remarkable tumor‐targeting photodynamic therapeutic effect by using an ultralow‐power lamp light (18 mW cm?2). This study thus not only extends the applications scope of AIEgens, but also offers useful insights into designing a new generation of cancer theranostics.  相似文献   

3.
Design and synthesis of new fluorophores with emission in the second near‐infrared window (NIR‐II, 1000–1700 nm) have fueled the advancement of in vivo fluorescence imaging. Organic NIR‐II probes particularly attract tremendous attention due to excellent stability and biocompatibility, which facilitate clinical translation. However, reported organic NIR‐II fluorescent agents often suffer from low quantum yield and complicated design. In this study, the acceptor unit of a known NIR‐I aggregation‐induced emission (AIE) luminogen (AIEgen) is molecularly engineered by varying a single atom from sulfur to selenium, leading to redshifted absorption and emission spectra. After formulation of the newly prepared AIEgen, the resultant AIE nanoparticles (referred as L897 NPs) have an emission tail extending to 1200 nm with a high quantum yield of 5.8%. Based on the L897 NPs, noninvasive vessel imaging and lymphatic imaging are achieved with high signal‐to‐background ratio and deep penetration. Furthermore, the L897 NPs can be used as good contrast agents for tumor imaging and image‐guided surgery due to the high tumor/normal tissue ratio, which peaks at 9.0 ± 0.6. This work suggests a simple strategy for designing and manufacturing NIR‐II AIEgens and demonstrates the potential of NIR‐II AIEgens in vessel, lymphatic, and tumor imaging.  相似文献   

4.
Precise diagnostics are of significant importance to the optimal treatment outcomes of patients bearing brain tumors. NIR‐II fluorescence imaging holds great promise for brain‐tumor diagnostics with deep penetration and high sensitivity. This requires the development of organic NIR‐II fluorescent agents with high quantum yield (QY), which is difficult to achieve. Herein, the design and synthesis of a new NIR‐II fluorescent molecule with aggregation‐induced‐emission (AIE) characteristics is reported for orthotopic brain‐tumor imaging. Encapsulation of the molecule in a polymer matrix yields AIE dots showing a very high QY of 6.2% with a large absorptivity of 10.2 L g?1 cm?1 at 740 nm and an emission maximum near 1000 nm. Further decoration of the AIE dots with c‐RGD yields targeted AIE dots, which afford specific and selective tumor uptake, with a high signal/background ratio of 4.4 and resolution up to 38 µm. The large NIR absorptivity of the AIE dots facilitates NIR‐I photoacoustic imaging with intrinsically deeper penetration than NIR‐II fluorescence imaging and, more importantly, precise tumor‐depth detection through intact scalp and skull. This research demonstrates the promise of NIR‐II AIE molecules and their dots in dual NIR‐II fluorescence and NIR‐I photoacoustic imaging for precise brain cancer diagnostics.  相似文献   

5.
Two‐photon photodynamic therapy (PDT) is able to offer precise 3D manipulation of treatment volumes, providing a target level that is unattainable with current therapeutic techniques. The advancement of this technique is greatly hampered by the availability of photosensitizers with large two‐photon absorption (TPA) cross section, high reactive‐oxygen‐species (ROS) generation efficiency, and bright two‐photon fluorescence. Here, an effective photosensitizer with aggregation‐induced emission (AIE) characteristics is synthesized, characterized, and encapsulated into an amphiphilic block copolymer to form organic dots for two‐photon PDT applications. The AIE dots possess large TPA cross section, high ROS generation efficiency, and excellent photostability and biocompatibility, which overcomes the limitations of many conventional two‐photon photosensitizers. Outstanding therapeutic performance of the AIE dots in two‐photon PDT is demonstrated using in vitro cancer cell ablation and in vivo brain‐blood‐vessel closure as examples. This shows therapy precision up to 5 µm under two‐photon excitation.  相似文献   

6.
Bioconjugation of quantum dots has resulted in a significant increase in resolution of biological fluorescent labeling. This intrinsic property of quantum dots can be utilized for sensitive detection of target analytes with high sensitivity; including pathogenic bacteria and cancer monitoring. The quantum dots and quantum dot doped silica nanoparticles exhibit prominent emission peaks when excited at 400 nm but on conjugation to model rabbit antigoat antibodies exhibit diminished intensity of emission peak at 600 nm. It shows that photoluminescence intensity of conjugated quantum dots and quantum dot doped silica nanoparticles could permit the detection of bioconjugation. Samples of conjugated and unconjugated quantum dots and quantum dot doped silica nanoparticles were subjected to enzyme linked immunosorbent assay for further confirmation of bioconjugation. In the present study ligand exchange, bioconjugation, fluorescence detection of bioconjugated quantum dots and quantum dot doped silica nanoparticles and further confirmation of bioconjugation by enzyme linked immunosorbent assay has been described.  相似文献   

7.
Photodynamic therapy (PDT) and photothermal therapy (PTT) are two kinds of treatment for tumors. Herein, a new aggregation‐induced emission (AIE)gen (MeO‐TPE‐indo, MTi) is synthesized with a D–π–A conjugated structure. MTi, which has an electron donor and an acceptor on a tetraphenylethene (TPE) conjugated skeleton, can induce the effective generation of reactive oxygen species (ROS) for PDT. With the guide of the indolium group, MTi can target and image mitochondrion selectively. In order to get good dispersion in water and long‐time retention in tumors, MTi is modified on the surface of polydopamine nanoparticles (PDA NPs) to form the nanocomposite (PDA‐MeO‐TPE‐indo, PMTi ) by π–π and hydrogen interactions. PMTi is a nanoscale composite for imaging‐guided PDT and PTT in tumor treatment, which is constructed with AIEgens and PDA for the first time. The organic functional molecules are combined with nanomaterials for building a multifunctional diagnosis and treatment platform by utilizing the advantages of both sides.  相似文献   

8.
One of the major pursuits of biomedical science is to develop advanced strategies for theranostics, which is expected to be an effective approach for achieving the transition from conventional medicine to precision medicine. Supramolecular assembly can serve as a powerful tool in the development of nanotheranostics with accurate imaging of tumors and real-time monitoring of the therapeutic process upon the incorporation of aggregation-induced emission (AIE) ability. AIE luminogens (AIEgens) will not only enable fluorescence imaging but will also aid in improving the efficacy of therapies. Furthermore, the fluorescent signals and therapeutic performance of these nanomaterials can be manipulated precisely owing to the reversible and stimuli-responsive characteristics of the supramolecular systems. Inspired by rapid advances in this field, recent research conducted on nanotheranostics with the AIE effect based on supramolecular assembly is summarized. Here, three representative strategies for supramolecular nanomaterials are presented as follows: a) supramolecular self-assembly of AIEgens, b) the loading of AIEgens within nanocarriers with supramolecular assembly, and c) supramolecular macrocycle-guided assembly via host–guest interactions. Meanwhile, the diverse applications of such nanomaterials in diagnostics and therapeutics have also been discussed in detail. Finally, the challenges of this field are listed in this review.  相似文献   

9.
Circularly polarized luminescent (CPL) materials are currently attracting great interest. While a chiral building is usually necessary in order to obtain CPL materials, here, this study proposes a general approach for fabricating 1D circularly polarized luminescent nanoassemblies from achiral aromatic molecules or aggregation‐induced emissive compounds (AIEgens). It is found that a C3 symmetric chiral gelator can individually form hexagonal nanotube structures and encapsulate the guest molecules. When achiral AIEgens are encapsulated into the confined nanotubes via organogelation, the AIEgens will emit circularly polarized luminescence. Further, the direction of the CPL could be controlled by the supramolecular chirality of the nanotube. Remarkably, the approach is universal and various kinds of the AIEgens can be doped to show such property, providing a full‐color‐tunable circularly polarized luminescence.  相似文献   

10.
Nonlinear optical microscopy has become a powerful tool in bioimaging research due to its unique capabilities of deep optical sectioning, high‐spatial‐resolution imaging, and 3D reconstruction of biological specimens. Developing organic fluorescent probes with strong nonlinear optical effects, in particular third‐harmonic generation (THG), is promising for exploiting nonlinear microscopic imaging for biomedical applications. Herein, a simple method for preparing organic nanocrystals based on an aggregation‐induced emission (AIE) luminogen (DCCN) with bright near‐infrared emission is successfully demonstrated. Aggregation‐induced nonlinear optical effects, including two‐photon fluorescence (2PF), three‐photon fluorescence (3PF), and THG, of DCCN are observed in nanoparticles, especially for crystalline nanoparticles. The nanocrystals of DCCN are successfully applied for 2PF microscopy at 1040 nm NIR‐II excitation and THG microscopy at 1560 nm NIR‐II excitation, respectively, to reconstruct the 3D vasculature of the mouse cerebral vasculature. Impressively, the THG microscopy provides much higher spatial resolution and brightness than the 2PF microscopy and can visualize small vessels with diameters of ≈2.7 µm at the deepest depth of 800 µm in a mouse brain. Thus, this is expected to inspire new insights into the development of advanced AIE materials with multiple nonlinearity, in particular THG, for multimodal nonlinear optical microscopy.  相似文献   

11.
Fluorescence imaging in the spectral region beyond the conventional near‐infrared biological window (700–900 nm) can theoretically afford high resolution and deep tissue penetration. Although some efforts have been devoted to developing a short‐wave infrared (SWIR; 900–1700 nm) imaging modality in the past decade, long‐wavelength biomedical imaging is still suboptimal owing to the unsatisfactory materials properties of SWIR fluorophores. Taking advantage of organic dots based on an aggregation‐induced emission luminogen (AIEgen), herein microscopic vasculature imaging of brain and tumor is reported in living mice in the SWIR spectral region. The long‐wavelength emission of AIE dots with certain brightness facilitates resolving brain capillaries with high spatial resolution (≈3 µm) and deep penetration (800 µm). Owning to the deep penetration depth and real‐time imaging capability, in vivo SWIR microscopic angiography exhibits superior resolution in monitoring blood–brain barrier damage in mouse brain, and visualizing enhanced permeability and retention effect in tumor sites. Furthermore, the AIE dots show good biocompatibility, and no noticeable abnormalities, inflammations or lesions are observed in the main organs of the mice. This work will inspire new insights on development of advanced SWIR techniques for biomedical imaging.  相似文献   

12.
Aggregation‐induced emission (AIE) is a beneficial strategy for generating highly effective solid‐state molecular luminescence without suffering losses in quantum yield. However, the majority of reported AIE‐active molecules exhibit only strong fluorescence, which is not ideal for electrical excitation in organic light‐emitting diodes (OLEDs). By introducing various substituent groups onto the biscarbazole compound, a series of molecular materials with aggregation‐induced phosphorescence (AIP) is designed, which exhibits two distinctly different phosphorescence bands and an absolute solid‐state room‐temperature phosphorescence quantum yield up to 64%. Taking advantage of the AIE feature, the AIP molecules are fabricated into OLEDs as a homogeneous light‐emitting layer, which allows for relatively small efficiency roll‐off and shows an external electroluminescence quantum yield of up to 5.8%, more than the theoretical limit for purely fluorescent OLED devices. The design showcases a promising strategy for the production of cost‐effective and highly efficient OLED technology.  相似文献   

13.
Herein, a highly stable aggregation‐induced emission (AIE) fluorescent nanodot assembled by an amphiphilic quinoxalinone derivative‐peptide conjugate, namely Quino‐1‐Fmoc‐RACR (also termed as Q1‐PEP), which exhibits large Stokes shift and an endoplasmic reticulum (ER)‐targeting capacity for bioimaging is reported. It is found that the resulting nanodot can effectively enter the ER with high fluorescent emission. As the ER is mainly involved in the transport of synthesized proteins in vesicles to the Golgi or lysosomes, the Q1‐PEP nanodot with ER‐targeting capacity can be used to monitor vesicular transport inside the cells. Compared to conventional fluorescent dyes with small Stokes shifts, the self‐assembled fluorescent nanodot shows superior resistance to photobleaching and aggregation‐induced fluorescence quenching, and elimination of the spectra overlap with autofluorescence of biosubstrate owning to their AIE‐active and red fluorescence emission characteristics. All these optical properties make the fluorescent nanodot suitable for noninvasive and long‐term imaging both in vitro and in vivo.  相似文献   

14.
Stimulated emission depletion (STED) nanoscopy is a typical super‐resolution imaging technique that has become a powerful tool for visualizing intracellular structures on the nanometer scale. Aggregation‐induced emission (AIE) luminogens are ideal fluorescent agents for bioimaging. Herein, long‐term super‐resolution fluorescence imaging of cancer cells, based on STED nanoscopy assisted by AIE nanoparticles (NPs) is realized. 2,3‐Bis(4‐(phenyl(4‐(1,2,2‐triphenylvinyl)phenyl)amino)phenyl) fumaronitrile (TTF), a typical AIE luminogen, is doped into colloidal mesoporous silica to form fluorescent NPs. TTF@SiO2 NPs bear three significant features, which are all essential for STED nanoscopy. First, their STED efficiency can reach more than 60%. Second, they are highly resistant to photobleaching, even under long‐term and high‐power STED light irradiation. Third, they have a large Stokes' shift of ≈150 nm, which is beneficial for restraining the fluorescence background induced by the STED light irradiation. STED nanoscopy imaging of TTF@SiO2‐NPs‐stained HeLa cells is performed, exhibiting a high lateral spatial resolution of 30 nm. More importantly, long‐term (more than half an hour) super‐resolution cell imaging is achieved with low fluorescence loss. Considering that AIE luminogens are widely used for organelle targeting, cellular mapping, and tracing, AIE‐NPs‐based STED nanoscopy holds great potential for many basic biomedical studies that require super‐resolution and long‐term imaging.  相似文献   

15.
Organic microlasers have attracted much attention due to their unique features such as high mechanical flexibility, facile doping of gain materials, high optical quality, simplicity and low‐cost fabrication. However, organic gain materials usually suffer from aggregation‐caused quenching (ACQ), preventing further advances of organic microlasers. Here, a new type of microlaser from aggregation‐induced emission (AIE) material is successfully demonstrated. By introducing a typical noncrystalline AIE material, a high quality microlaser is obtained via a surface tension‐induced self‐assembly approach. Distinct from conventional organic microlasers, the organic luminescent material used here is initially nonluminescent but can shine after aggregation under optical pumping. Further investigations demonstrate that AIE‐based microlasers exhibit advantages to enable much higher doping concentrations, which provides an alternative way to improved lasing performance including dramatically reduced threshold and favorable lasing stability. It is believed that these results could provide a promising way to extend the content of microlasers and open a new avenue to enable applications ranging from chemical sensing to biology.  相似文献   

16.
A simple strategy is developed to prepare eccentrically or homogeneously loaded nanoparticles (NPs) using poly (DL‐lactide‐co‐glycolide) (PLGA) as the encapsulation matrix in the presence of different amounts of polyvinyl alcohol (PVA) as the emulsifier. Using 2,3‐bis(4‐(phenyl(4‐(1,2,2‐triphenylvinyl)‐phenyl)amino)‐phenyl)‐fumaronitrile (TPETPAFN), a fluorogen with aggregation‐induced emission (AIE) characteristics, as an example, the eccentrically loaded PLGA NPs show increased fluorescence quantum yields (QYs) as compared to the homogeneously loaded ones. Field emission transmission electron microscopy and fluorescence lifetime measurements reveal that the higher QY of the eccentrically loaded NPs is due to the more compact aggregation of AIE fluorogens that restricts intramolecular rotations of phenyl rings, which is able to more effectively block the non‐radiative decay pathways. The eccentrically loaded NPs show far red/near infrared emission with a high fluorescence QY of 34% in aqueous media. In addition, by using poly([lactide‐co‐glycolide]‐b‐folate [ethylene glycol]) (PLGA‐PEG‐folate) as the co‐encapsulation matrix, the obtained NPs are born with surface folic acid groups, which are successfully applied for targeted cellular imaging with good photostability and low cytotoxicity. Moreover, the developed strategy is also demonstrated for inorganic‐component eccentrically or homogeneously loaded PLGA NPs, which facilitates the synthesis of polymer NPs with controlled internal architectures.  相似文献   

17.
Aggregation‐induced emission (AIE) is commonly observed in irregular bulk form. Herein, unique aggregation properties of an AIE‐active complex into branched supramolecular wires are reported for the first time. Mono‐cyclometalated Ir(III) complex shows in‐plane J‐aggregation at the air–water interface owing to the restriction of intramolecular vibration of bidentate phenylpyridinato and intramolecular rotations of monodentate triphenylphosphine ligands at air–water interface. As a consequence, a large enhancement of luminescence comparable to the solid state is obtained from the monolayers of supramolecular wires. This unique feature is utilized for the fabrication of light‐emitting diodes with low threshold voltage using supramolecular wires as active layer. This study opens up the need of ordered assembly of AIE complexes to achieve optimal luminescence characteristics.  相似文献   

18.
Visualization of the brain in its native environment is important for understanding common brain diseases. Herein, bright luminogens with remarkable aggregation-induced emission (AIE) characteristics and high quantum yields of up to 42.6% in the solid state are synthesized through facile reaction routes. The synthesized molecule, namely BTF, shows ultrabright far-red/near-infrared emission and can be fabricated into AIE dots by a simple nanoprecipitation procedure. Due to their high brightness, large Stokes shift, good biocompatibility, satisfactory photostability, and large three-photon absorption cross section, the AIE dots can be utilized as efficient fluorescent nanoprobes for in vivo brain vascular imaging through the intact skull by a three-photon fluorescence microscopy imaging technique. This is the first example of using AIE dots for the visualization of the cerebral stroke process through the intact skull of a mouse with high penetration depth and good image contrast. Such good results are anticipated to open up a new venue in the development of efficient emitters with strong nonlinear optical effects for noninvasive bioimaging of living brain.  相似文献   

19.
Building humidity sensors possessing the features of diverse‐configuration compatibility, and capability of measurement of spatial and temporal humidity gradients is of great interest for highly integrated electronics and wearable monitoring systems. Herein, a visual sensing approach based on fluorescent imaging is presented, by assembling aggregation‐induced‐emission (AIE)‐active molecular rotors into a moisture‐captured network; the resulting AIE humidity sensors are compatible with diverse applications, having tunable geometries and desirable architectures. The invisible information of relative humidity (RH) is transformed into different fluorescence colors that enable direct observation by the naked eyes based on the twisted intramolecular charge‐transfer effect of the AIE‐active molecular rotors. The resulting AIE humidity sensors show excellent performance in terms of good sensitivity, precise quantitative measurement, high spatial–temporal resolution, and fast response/recovery time. Their multiscale applications, such as regional environmental RH detection, internal humidity mapping, and sensitive human‐body humidity sensing are demonstrated. The proposed humidity visualization strategy may provide a new insight to develop humidity sensors for various applications.  相似文献   

20.
Controlling chain behavior through smart molecular design provides the potential to develop ultrastable and efficient deep‐blue light‐emitting conjugated polymers (LCPs). Herein, a novel supramolecular self‐encapsulation strategy is proposed to construct a robust ultrastable conjugated polydiarylfluorene (PHDPF‐Cz) via precisely preventing excitons from interchain cross‐transfer/coupling and contamination from external trace H2O/O2. PHDPF‐Cz consists of a mainchain backbone where the diphenyl groups localize at the 9‐position as steric bulk moieties, and carbazole (Cz) units localize at the 4‐position as supramolecular π‐stacked synthon with the dual functionalities of self‐assembly capability and hole‐transport facility. The synergistic effect of the steric bulk groups and π‐stacked carbazoles affords PHDPF‐Cz as an ultrastable property, including spectral, morphological stability, and storage stability. In addition, PHDPF‐Cz spin‐coated gelation films also show thickness‐insensitive deep‐blue emission with respect to the reference polymers, which are suitable to construct solution‐processed large‐scale optoelectronic devices with higher reproducibility. High‐quality and uniform deep‐blue emission is observed in large‐area solution‐processed films. The electroluminescence shows high‐quality deep‐blue intrachain emission with a CIE (0.16, 0.12) and a very narrow full width at half‐maximum of 32 nm. Finally, large‐area and flexible polymer light‐emitting devices with a single‐molecular excitonic behavior are also fabricated. The supramolecular self‐encapsulation design provides an effective strategy to construct ultrastable LCPs for optoelectronic applications.  相似文献   

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