Discrimination of complex analytes is an attractive and important issue. We have prepared a number of novel poly(aryleneethynylene)s (PAE) that are water soluble, and fluorescent and have investigated their use as fluorescent sensors fields. The mechanism of sensing is the differential quenching of fluorescence of the different PAEs. The resulting complex pattern of fluorescence quenching is investigated using linear discriminant analysis and principal component analysis. The obtained patterns allow the direct discrimation of different white wines, juices, whiskies, but are also useful for discrimination of different drug types. A particular interesting aspect is the discrimination of different commercial samples of acetyl salicyclic acids or ibuprofens that all could be discriminated.
The employed sensor arrays are normally not very large but contain around 3-6 elements. That suffices to analyze even the most complex analytes with a hypothesis-free sensor field.
11:00am - 11:15am Oral
AIE Probes for Biomedical Applications
National University of Singapore, Singapore
Fluorogens with aggregataion-induced emission (AIE) characteristics have recently aroused significant research interest. The unique AIE process offers a straightforward solution to the aggregation-caused quenching problem faced by traditional fluorophores. In this talk, we summarize our recent AIE work to highlight the utility of AIE effect in the development of new fluorescent bioprobes, which allows the use of highly concentrated fluorogens for biosensing and imaging.The simple design and fluorescence turn-on feature of the molecular AIE bioprobes offer direct visualization of specific analytes and biological processes in aqueous media with higher sensitivity and better accuracy than traditional fluorescence turn-off probes. The AIE dot-based bioprobes with different formulations and surface functionalities show advanced features over quantum dots and small molecule dyes, such as large absorptivity, high luminosity, excellent biocompatibility, free of random blinking, and strong photobleaching resistance. In addition, our recent discovery that AIE fluorogens with strong reactive oxygen species generation in solid state further expanded their applications to cancer therapy.These features enable cancer cell detection, long term cell tracing, and image-guided therapy in a noninvasive and high contrast manner.
11:15am - 11:30am Oral
Multi-Color Emissions and Polymorphs of an AIEgen Induced by Freezing and Surfactant-Assisted Self-Assembly
Some aggregation-induced emission (AIE) substances show morphology-dependent emissions, the preparation of diverse morphologies from one AIEgen with simple physical methods remains a challenge. Di(4-propoxyphenyl) dibenzofulvene (DBF) exhibits multiple switchable colors corresponding to different aggregation morphologies. We firstly employed freezing-thawing (F-T) method to adjust the morphologies of DBF and hence its emissions. When treated with F-T, the emissions of DBF in the solid state or in acetonitrile/water dispersions are all blue-shifted. Especially, the DBF dispersions containing poly(N-vinylpyrrolidone) (PVP) and acrylamide (AAm) undergo gradual and more significant blue-shift in λem with F-T cycles, further blue-shifts in λem are found when F-T treated dispersions are gelated or just kept for some times. Our recent work also proves that polymorphs can be obtained with only one AIEgen with the assistance of surfactants. By varying surfactant type and concentration, various morphologies of DBF aggregates with different sizes and shapes, such as microsized spherical particles, lines, dendritic structures, needles, as well as large and long thin sheets, are obtained. Yellow-emitting DBF aggregates are commonly formed in the dispersions with all types of surfactants, while green-emitting aggregates are more commonly formed in the dispersions with a high concentration of Pluronic F-127 and the mixed surfactants of cetyl trimethylammonium bromide (CTAB) and sodium dodecylbenzene sulfonate (SDBS). Very impressively, green-emitting hexagonal and rhombic thin sheets and multifaceted 3D structures are also obtained.
We thank the financial supports from the National Natural Science Foundation of China (No. 21574015).
11:30am - 11:45am Oral
Conjugated Polymer Photosensitizers for Effective Image-Guided Therapy
Wenbo WU, Bin LIU
National University of Singapore, Singapore
Photodynamic therapy (PDT), an emerging treatment method that using photosensitizers (PS) and light as agents instead of traditional chemical drugs,has attracted much attention in recent years, due to its high spatiotemporal precision, controllability, and noninvasive properties, etc. Using PSs with both bright emission and efficient singlet oxygen (1O2) generation to realize image-guided PDT represents a new research direction, in which PSs play a very important role. In this contribution, we reported some high effective conjugated polymer (CP) PSs with bright AIE FR/NIR emission. In comparison with their small molecule analogue, the CP PSs showed much effecitve 1O2 generation under light irradiation. Both in vitro and in vivo experiment showed the CP PS based nanoparticles (NPs) can be good candidates for image-guided therapy.
11:45am - 12:00pm Oral
Preparation and Biomedical Applications of Nanomaterials with Aggregation-Induced Emission Characteristics
Nankai University, China
We report a quantum dot-sized organic dot with aggregation-induced emission (AIE) characteristics as a promising cell tracker for noninvasive long-term tracking of adipose-derived stem cells (ADSCs) in living mice. We demonstrate that the AIE dots possess high fluorescence, strong photobleaching resistance, low in vivo toxicity, excellent retention in living ADSCs and negligible interference on the ADSC pluripotency and secretome. The AIE dots also exhibit far superior in vitro cell tracking capability as compared to the widely used commercial cell trackers of PKH26 and Qtracker 655. The in vivo studies using an ischemic hind limb-bearing mouse model reveal that the AIE dots can precisely and quantitatively report the fate of ADSCs and their therapeutic effect in vivo for 6 weeks.Moreover, we have also synthesized a far-red/near-infrared fluorescent AIEgen-based nanodot, which can efficiently generate reactive oxygen species (ROS) under light irradiation. It is found that the AIEgen-based nanodots are able to visualize tumor tissues and assess tumor margins during surgery in a tumor-bearing mouse model. More importantly, upon tumor removal followed by irradiation of the incision site with light, the AIE nanodots in the residual tumors will generate ROS, which has been demonstrated to successfully suppress the residual tumors and reduce the risk of tumor recurrence after debulking surgery.