75 research outputs found
No UV Irradiation Needed! Chemiexcited AIE Dots for Cancer Theranostics
No full textIn this issue of Chem, Liu and coworkers have developed a novel theranostic system based on nanoparticles with aggregation-induced emission characteristics (AIE dots), which emit long-wavelength chemiluminescence (CL) and generate singlet oxygen upon chemiexcitation by H2O2, offering a new strategy for CL image-guided tumor therapy. In this issue of Chem, Liu and coworkers have developed a novel theranostic system based on nanoparticles with aggregation-induced emission characteristics (AIE dots), which emit long-wavelength chemiluminescence (CL) and generate singlet oxygen upon chemiexcitation by H2O2, offering a new strategy for CL image-guided tumor therapy.</p
A new ratiometric fluorescence detection of heparin based on the combination of the aggregation-induced fluorescence quenching and enhancement phenomena
No full textControllable Self‐Assembly of Di(p‐methoxylphenyl)Dibenzofulvene into Three Different Emission Forms
No full textManipulation of Nonradiative Process Based on the Aggregation Microenvironment to Customize Excited-State Energy Conversion
No full textConspectusNonradiative processes with
the determined role in excited-state
energy conversion, such as internal conversion (IC), vibrational relaxation
(VR), intersystem crossing (ISC), and energy or electron transfer
(ET or eT), have exerted a crucial effect on biological functions
in nature. Inspired by these, nonradiative process manipulation has
been extensively utilized to develop organic functional materials
in the fields of energy and biomedicine. Therefore, comprehensive
knowledge and effective manipulation of sophisticated nonradiative
processes for achieving high-efficiency excited-state energy conversion
are quintessential. So far, many strategies focused on molecular engineering
have demonstrated tremendous potential in manipulating nonradiative
processes to tailor excited-state energy conversion. Besides, molecular
aggregation considerably affects nonradiative processes due to their
ultrasensitivity, thus providing us with another essential approach
to manipulating nonradiative processes, such as the famous aggregation-induced
emission. However, the weak interactions established upon aggregation,
namely, the aggregation microenvironment (AME), possess hierarchical,
dynamic, and systemic characteristics and are extremely complicated
to elucidate. Revealing the relationship between the AME and nonradiative
process and employing it to customize excited-state energy conversion
would greatly promote advanced materials in energy utilization, biomedicine,
etc., but remain a huge challenge. Our group has devoted much effort
to achieving this goal.In this Account, we focus on our recent
developments in nonradiative
process manipulation based on AME. First, we provide insight into
the effect of the AME on nonradiative process in terms of its steric
effect and electronic regulation, illustrating the possibility of
nonradiative process manipulation through AME modulation. Second,
the distinct enhanced steric effect is established by crystallization
and heterogeneous polymerization to conduct crystallization-induced
reversal from dark to bright excited states and dynamic hardening-triggered
nonradiative process suppression for highly efficient luminescence.
Meanwhile, promoting the ISC process and stabilizing the triplet state
are also manipulated by the crystal and polymer matrix to induce room-temperature
phosphorescence. Furthermore, the strategies employed to exploit nonradiative
processes for photothermy and photosensitization are reviewed. For
photothermal conversion, besides the weakened steric effect with promoted
molecular motions, a new strategy involving the introduction of diradicals
upon aggregation to narrow the energy band gap and enhance intermolecular
interactions is put forward to facilitate IC and VR for high-efficiency
photothermal conversion. For photosensitization, both the enhanced
steric effect from the rigid matrix and the effective electronic regulation
from the electron-rich microenvironment are demonstrated to facilitate
ISC, ET, and eT for superior photosensitization. Finally, we explore
the existing challenges and future directions of nonradiative process
manipulation by AME modulation for customized excited-state energy
conversion. We hope that this Account will be of wide interest to
readers from different disciplines
Organic Luminogens
No full textSmall molecule compounds having aggregation-induced emission (AIE) characteristics. The compounds include organic, aromatic salts having anion-π+ interactions. In some embodiments, the anion-π+ interaction can include heavy-atom-anion-π+ interactions. The heavy atom anions can include bromine or iodide, for example. The compounds can be water-soluble. The compounds can be useful as probes for bioimaging, as room temperature luminogens for electroluminescent devices, and white organic light-emitting applications
A New Fluorescence Turn-on Assay for Trypsin and Inhibitor Screening Based on Graphene Oxide
No full textAggregation-Induced Emission : Mechanistic Study of Clusteroluminescence of Tetrathienylethene
No full textIn this work we have investigated the aggregation-induced emission (AIE) behaviour of 1,1,2,2-tetra(thiophen-2-yl)ethene (tetrathienylethene, TTE). The semi-locked and fully-locked derivatives (sl-TTE and fl-TTE) have been synthesized to better understand the mechanism behind the solid state photoluminescence of TTE. TTE is a typical AIEgen and its luminescence can be explained through the mechanistic understanding of the restriction of intramolecular motions (RIM). The emissive behaviour of TTE in the THF/water aggregates and crystal state have also been studied revealing a remarkable red-shift of 35 nm. A similar red-shift emission of 37 nm from the THF/water aggregates to the crystal state, is also observed for (E)-1,2-di(thiophen-2-yl)ethene (trans-dithienylethene, DTE). Crystal analysis has revealed that the emission red-shifts are ascribable to the presence of strong sulfur-sulfur (S···S) intra- and intermolecular interactions that are as close as 3.669 Å for TTE and 3.679 Å for DTE, respectively. These heteroatom interactions could help explain the photoluminescence of non-conventional luminophores as well as luminescence of non-conjugated biomacromolecules
A New Fluorescence Turn-on Assay for Trypsin and Inhibitor Screening Based on Graphene Oxide
No full textIn this paper, we describe a new continuous fluorescence turn-on method for trypsin assay and inhibitor screening in situ. This assay is designed based on the following assumptions: (1) It is expected that the fluorescein-labeled peptide composed of six arginine residues (Arg6-FAM) with positive charges will interact with the negatively charged edge of water-soluble graphene oxide (GO) because of electrostatic interactions to form a GO/Arg6-FAM complex. As a result, the fluorescence of fluorescein will be quenched because of the energy transfer from fluorescein to GO. (2) Arg6-FAM can be hydrolyzed into small fragments in the presence of trypsin, and accordingly, the GO/Arg6-FAM complex will be dissociated, gradually leading to fluorescence recovery for the solution. In this way, the trypsin activity can be easily assayed with the ensemble of Arg6-FAM and GO. Additionally, the ensemble can be employed for screening of the inhibitors of trypsin
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