Aggregation-Induced Emission (AIE) Ben Zhong Tang Hong Kong University of Science & Technology (HKUST) Clear Water Bay Campus HKUST
OUTLINE Background and Motivation Aggregation-Induced Emission Technological Applications Conclusion & Acknowledgement Clear Water Bay Campus, Hong Kong University of Science & Technology
Light emission: a useful yet mysterious process to the humankind 3
Jablonski Diagram
Organic Light-Emitting Diode (OLED)
Adv Fluorescent Bioprobes Fast response High sensitivity Low cytotoxicity In-situ workability Simple operation Excellent portability On Site In Time In Vivo 6 6
A Thorny Issue in the Area Concentration Quenching First discovered by Förster in 1954 Now a general belief in the area A molecule quenches its own fluorescence at high concentration, partially due to aggregate formation (hence aggregation-caused quenching or ACQ). Common organic dyes show marked concentration quenching effects. http://www.prsbio.com/index.html (Photonic Research Systems)
Seeing Is Believing: Examples of ACQ Effect O N O Water content (vol %) Br Br O N O 0 10 20 30 40 50 60 70 80 90 THF Solution Aggregate 8 Chem. Soc. Rev. 2011, 40, 5361.
Seeing is believing: Examples of ACQ effects FITC-Labeled Chitosan 0.09% 0.11% 0.52% J. Am. Chem. Soc. 2013, 135, 8238.
ACQ: a theoretically well understood phenomenon but practically harmful effect Organic light-emitting diode (solid state) Biological probe (aqueous surrounding) Environmental monitor (water pollution) Optical Display Ecosystem protection Cellular Imaging
Research efforts to solve the ACQ problem by hampering chromophore aggregation have ended with limited success. Organic luminophores with conjugated structures naturally aggregate in the solid state and aqueous media! It will be great, if chromophore aggregates can luminesce efficiently!
OUTLINE Background and Motivation Aggregation-Induced Emission Technological Applications Conclusion & Acknowledgement Clear Water Bay Campus, Hong Kong University of Science & Technology
An Anti-ACQ Photophysical Phenomenon Water Fraction (vol %) Emissive aggregates 0 60 70 80 85 90 95 Nonemissive solutions 1,1,2,3,4,5-Hexaphenylsilole (HPS) Chem. Commun. 2001, 1740.
C&EN 2001, 79 (41), 29. Aggregation- Induced Emission (AIE)
Visco- and Thermochromisms (External Controls) 10000 temp ( o C) Peak intensity (au) 1000 100 PL intensity (au) -196-78 -18 0 23 10 0 30 60 90 Glycerol fraction (vol %) 410 510 610 710 Wavelength (nm) Chem. Mater. 2003, 15, 1535. Restriction of Intramolecular Rotations (RIR) 15
Covalent Bonding (Internal Control) Chem. Commun. 2012, 48, 10675.
Restriction of Intramolecular Rotations (RIR) HPS Restriction of intramolecular Rotations (RIR) AIE Acc. Chem. Res. 2013, 46, 2441. Nonemissive Emissive (on) Dynamic intramolecular rotations in the solution state Intramolecular motions restricted in the aggregate state Propeller-shape prevents p-p interaction in the aggregates
Color covering whole visible range (extending to NIR) Luminescence quantum yield up to unity (100%) Suspended Nanoparticles Solid powders
OUTLINE Background and Motivation Aggregation-Induced Emission Technological Applications Conclusion & Acknowledgement Clear Water Bay Campus, HKUST
Optoelectronic Devices Chemical sensors Biological probes 20
Optoelectronic Devices (Full-Color OLEDs) Blue Green Yellow Red White Simple device structure & low manufacture cost External quantum efficiency up to theoretic limit White OLEDs with excellent device performances
Mechanochromism and Thermochromism Very common for AIE luminogens Adv. Mater. 2011, 23, 3261. J. Am. Chem. Soc. 2012, 134, 9956.
Multiple Chromic AIE Systems Touching UV vis UV vis Applications as fluorescent anti-counterfeiting materials
Chemical Probes for Environmental Protection Specific and Sensitive Detection of Toxic Heavy-Metal Ions
Detection and Quantitation of CO2 Gas J. Am. Chem. Soc. 2010, 132, 13951. 25
Forensic Science (Criminal Investigation) 100 AIE fluorogen Relative Intensity (AU) 80 60 40 20 375-fold brighter! Solid microparticles 0 Conventional dye 400 450 500 550 600 650 Wavelength (nm)
Buy Time (On-site and In-time Tests on any Surfaces) Steel Uneven plastic tape
Visualization of Material Morphology
Fluorescent Bioprobes (Glucose) Relative Fluorescence Intensity 5.5 4.0 2.5 1.0 Glu Glu Fru Gal Man Fru Gal Man J. Am. Chem. Soc. 2011, 133, 660.
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AIE Luminogens Are Biocompatible Liver Kidney AST: aspartate aminotransferase ALT: alanine transaminase GGT: g-glutamyl transpeptidase BUN: blood urea nitrogen
AIE Map in Living Cells mitochondria cytoplasm membrane lysosome surface protein enzyme ph nucleus
Mitochondrial-Specific AIE-Active Bioprobes (Blue) J. Am. Chem. Soc. 2013, 135, 62. TPE-TPP MitoTracker Red FM Overlay
Mitochondrial-Specific AIE-Active Bioprobes (Green) TPE-IQ MitoTracker Red Overlay
Mitochondrial-Specific AIE Bioprobes (Yellow) J. Mater. Chem. C 2013, 1, 4640. 35
Mitochondrial-Specific AIE Bioprobes (Red)
ph Sensor Chem. Sci. 2012, 3, 1804. J. Am. Chem. Soc. 2013, 135, 4926. TPE-Cy-H TPE-Cy TPE-Cy-OH Wavelength (nm) ph
Cell ph Mapping (Intracellular ph Sensor) J. Am. Chem. Soc. 2013, 135, 4926.
Following Protein Fibrosis Processes Parkinson's, Alzheimer's and Huntington's diseases, cirrhosis, etc. J. Am. Chem. Soc. 2012, 134, 1680.
Integrin α v β 3 Sensing TPS-2cRGD BA-TPS TPS-2cRGD J. Am. Chem. Soc. 2012, 134, 9569.
Discrimination between Different Tumor Cells TPS-2cRGD Membrane tracker Overlay MCF-7 cells: low level of integrin α v β 3 receptor HT-29 cells (transfected): overexpressed integrin α v β 3 on cellular membrane J. Am. Chem. Soc. 2012, 134, 9569.
Real-Time Monitoring of Cell Apoptosis J. Am. Chem. Soc. 2012, 134, 17972.
J. Am. Chem. Soc. 2012, 134, 17972. J. Am. Chem. Soc. 2014, 134, 9569.
In Vivo Two-Photon Fluorescence Imaging of Inflammation A 10 min B 20 min 50 m C 30 min D 120 min E 120 min Inflamed blood vessel Control (Healthy blood vessel)
Differentiation between Live and Dead Bacteria Adv. Healthcare Mater. 2014, 3, 88.
Red/Near-IR Protein-Shelled Cytophilic AIE Dots Adv. Funct. Mater. 2012, 22, 771. Excreted from the body of the mouse but accumulated in the tumor due to EPR effect
Fabrication of Fluorescent & Magnetic AIE Dots Targeted drug delivery Magnetohyperthermia MRI, CT, etc. etc. Adv. Funct. Mater. 2011, 21, 1733.
Long-Term Cell Tracer Adv. Mater. 2011, 29, 3298. 48
Long-Term Cell Tracking Fluorescent images of the HeLa cells stained by the aggregates of the TPE-CS bioconjugate with a DL of 7.86 mol % at different passages. Numbers of passages are denoted by the Arabic numerals (1 15) on the right sides of the images. J. Am. Chem. Soc. 2013, 135, 8238.
Long-Term Tumor Tracking a 92 D0 D1 D3 D5 D12 90 x 10 7 88 b 86 32 30 28 x 10 7 26 24 22 12.5 D14 D17 D21 10 Tat-AIE dots 8 Qtracker @ 655 6 4 2 0 0 1 3 5 7 12 14 17 21 Time (day) D0 D1 D3 D5 D7 Integrated intensity (x10 9 ) 12 11.5 x 10 7 11 Sci. Rep. 2013, 3, 1150.
OUTLINE Background and Motivation Aggregation-Induced Emission Technological Applications Conclusion & Acknowledgement Clear Water Bay Campus, The Hong Kong University of Science & Technology
Summary Observed a unique anti-acq phenomenon: aggregation-induced emission (AIE) Established a working mechanism for AIE: restriction of intramolecular rotation (RIR) Explored a wide variety of technological applications for the AIE luminogens Chem. Soc. Rev. 2011, 40, 5361. Acc. Chem. Res. 2013, 46, 2441. Chem. Soc. Rev. 2014, 43, 4494. Adv. Mater. 2014, 26, in press.
CHEMISTR AND MATERIALS SCIENCE 53
AIE Research Is Fast Developing Papers in Each Year Citations in Each Year 1st AIE paper by Tang et al. Data retrieved from Web of Science using the keyword of Aggregation-Induced Emission
Examples of Potential Applications in Chemical Engineering 层流 湍流 径向混合 纵向混合
Research Grants Council of Hong Kong National Science Foundation of China Innovation & Technology Fund of Hong Kong Ministry of Science & Technology of China
An AIE Symposium to be held in Hawaii on 15 20 Dec 2015