Our Research is focusing on design and synthesis of novel organic materials that have potential applications in chemical biology and material science. We seek fundamental understanding on molecular interactions. The study aims to couple a specific chemical event into molecular switches, thereby generating large optical responses upon analyte binding.
Synthesis of Fluorescent Dyes with Intramolecular Proton Transfer. Intramolecular hydrogen bonding in certain molecules, such as 2-(2’-hydroxyphenyl)-1,3-benzoxazole (HBO) derivative, allows the excited-state intramolecular proton transfer (ESIPT) to occur. Materials with ESIPT properties often exhibit very large Stokes shift (>200 nm), and can generate two emission with very different wavelengths (e.g. simultaneous emission at ~530 nm and 700 nm). Coupling a specific analyte-binding event with ESIPT emission has led to selective recognition of biological important species, such as Zn2+, Al3+ and pyrophosphate. Remarkably, the ESIPT emission, induced by metal cation binding, can be tuned to near infrared region (e.g. 700-800 nm) for improved detection.
Seeking Fluorescent Dyes for Selective Interaction with Biomolecules. Through using combinatorial approach, we seek new dyes that can give fluorescence turn-on upon selective binding to biomolecules or tissues. A few dyes with different structures (such as Squaraines and flavonoid dyes) are found to give large fluorescence turn-on upon binding proteins. The target binding-activated fluorescence turn-on also leads to wash-free probes for organelle (such as mitochondrial or endoplasmic reticulum). The concept can be further expanded for selective recognition of certain biological cells for in vivo imaging.
Chu, D. A. Medvetz, Y. Pang “A Polymeric Sensor with Excited-State Intramolecular Proton Transfer: Its Response to Anionic Species.” Chem. Mater., 2007, 19, 6421-6429.
Yongqian Xu, Matthew Panzer, Xiaopeng Li, Wiley Youngs, Yi Pang, “Host-Guest Assembly of Squaraine Dye in Cucurbituril: Its Implication in Fluorescent Probe for Mercury Ions” Chem. Commun., 2010, 46, 4073-4075.
Yongqian Xu and Yi Pang, “Zinc Binding-Induced Near-Infrared Emission from Excited-State Intramolecular Proton Transfer of a Bis(benzoxazole) Derivative” Chem. Commun, 2010, 46, 4070-4072.
Yongqian Xu, Andrey Malkovskiy, Yi Pang, “A Graphene Binding-Promoted Fluorescence Enhancement for BSA Recognition.” Chem. Commun, 2011, 47, 6662-6664.
Weihua Chen, Yu Xing, Yi Pang, “A Highly Selective Pyrophosphate Sensor Based on ESIPT Turn-On in Water”, Org. Lett., 2011, 13, 1362-1365.
Weihua Chen, Eric Twum, Linlin Li, Brian Wright, Peter Rinaldi, Yi Pang, “Rotational Energy Barrier of 2- (2',6’-Dihydroxyphenyl)benzoxazole: A Case of Study by NMR." J. Org. Chem., 2012, 77, 285-290.
Yongqian Xu, Qin Liu, Bairui Dou, Brian Wright, Jingyun Wang and Yi Pang, “Zn2+ Binding-Enabled Excited State Intramolecular Proton Transfer: A Step toward New Near-Infrared Fluorescent Probes for Imaging Applications” Adv. Healthcare Mater., 2012, 1, 485-492.
Junfeng Wang, Yingbo Li, Ernest Duah, Sailaja Paruchuri, Demin Zhou, Yi Pang “A Selective NIR-Emitting Zinc Sensor by Using Schiff Base Binding to Turn-On Excited-State Intramolecular Proton Transfer.” J. Mater. Chem. B, 2014, 2, 2008 - 2012.
Bin Liu, Junfeng Wang, Ge Zhang, Ruke Bai, and Yi Pang, “A flavone-based ESIPT ratiometric chemodosimeter for detection of cysteine in living cells.” ACS Applied Materials & Interfaces, 2014, 6, 4402–4407.
Junfeng Wang, Xiumin Liu, Yi Pang “A Benzothiazole-Based Sensor for Pyrophosphate (PPi) and ATP: Mechanistic Insight for Anion-Induced ESIPT Turn-On.” J. Mater. Chem. B., 2014, 2, 6634-6638.
Junfeng Wang, Yingbo Li, Nikul G. Patel, Ge Zhang, Demin Zhou, Yi Pang, “Single Molecular Multi-analyte (Cr3+, Al3+ and Fe3+) Fluorescent Probe by naked eyes in Aqueous and Its Biological Applications.” Chem. Commun., 2014, 50, 12258-12261.
Bin Liu, Yi Pang, Rachida Bouhenni, Ernest Duah, Sailaja Paruchuri, Lucas McDonald “A Step toward Simplified Detection of Serum Albumin on SDS-PAGE Using an Environment-Sensitive Flavone Sensor.” Chem. Commun. 2015, 51, 11060 – 11063.
Kanokthorn Boonkitpatarakul, Junfeng Wang, Nakorn Niamnont, Bin Liu, Lucas McDonald, Yi Pang, Mongkol Sukwattanasinitt, “Novel turn-on fluorescent sensors with mega stoke shifts for dual detection of Al3+ and Zn2+”. ACS Sensors, 2016, 1, 144-150.
In the area of furan-derived materials
Jiping Ma, Zhongtian Du, Jie Xu, Qinghui Chu, Yi Pang, “Efficient Aerobic Oxidation of 5-Hydroxymethylfurfural to 2,5-Diformylfuran, and Synthesis of a Fluorescent Material”, ChemSusChem, 2011, 4, 51-54.
Jiping Ma, Yi Pang, Min Wang, Jie Xu, Hong Ma, and Xin Nie “The copolymerization reactivity of diols with 2,5-furandicarboxylic acid for furan-based copolyester materials” J. Mater. Chem., 2012, 22, 3457-3461.
Jiping Ma, Xinfei Yu, and Jie Xu, Yi Pang, “Synthesis and Crystallinity of Poly(butylene 2,5-furandicarboxylate).” Polymer, 2012, 53, 4145-4151.
Tengfei Xiang, Xiumin Liu, Ping Yi, Mingming Guo, Yusheng Chen, Chrys Wesdemiotis, Jie Xu, Yi Pang, “Schiff base polymers derived from 2,5-diformylfuran.” Polymer International, 2013, 62, 1517-1523.
In the area of polymer-CNT interaction
Wenhui Yi, Andrey Malkovskiy, Yongqian Xu, Xiao-Qian Wang,Alexei P. Sokolov, Marisabel Lebron Colon, Michael Meador, Yi Pang “Polymer Conformation-Assisted Wrapping of Single-Walled Carbon Nanotube: The Impact of cis-Vinylene Linkage” Polymer, 2010, 51, 475-481.
Yusheng Chen, Andrey Malkovskiy, Xiao-Qian Wang, Alexei P. Sokolov, Marisabel Lebron-Colon, Kelly Perry, Karren More, Yi Pang “Selection of Single-Walled Carbon Nanotube with Narrow Diameter Distribution by Using a PPE-PPV Copolymer” ACS Macro Lett., 2012, 1, 246-251.
Yusheng Chen, Yongqian Xu, Kelly Perry, Alexei P. Sokolov, Karren More, Yi Pang, “Achieving Diameter-Selective Separation of Single-Walled Carbon Nanotubes by Using Polymer Conformation-Confined Helical Cavity.” ACS Macro Lett., 2012, 1, 701–705.
Yusheng Chen, Yongqian Xu, Qiuming Wang, Rosi N. Gunasinghe, Xiao-Qian Wang, Yi Pang “Highly Selective Dispersion of Carbon Nanotubes by Using Poly(phenyleneethynylene)-Guided Supermolecular Assembly.” Small, 2013, 9, 870-875.