Our research interests are generally focused on solar energy conversion, bioanalytical chemistry and materials chemistry. Categorized as such, however, we often find it more exciting when we can disregard the boundaries and temporarily step out of our comfort zone. Over the past years, we have developed understanding and skills in electrochemistry, luminescence (spectroscopy and imaging) and various microfabrication techniques.
More than 80% of energy that is enabling our current lifestyle comes from fossil fuels, which are not only finite but can potentially trigger disastrous climate fluctuations. Solar energy can potentially cut our dependence on fossil fuels but current technologies suffer from high cost and low efficiency. To fully tap its potential, significant advancements both in fundamental understanding and technological innovation are needed in capture and storage of solar energy. Our approach to this complex problem is to use natural materials such as lipids to mimic natural photosynthesis - a truly sustainable system that is proven to work at the grandest scale for hundreds of millions of years. On the fundamental level, we're building photoconverting cells that contain only one or a few molecular layers of photoactive agents. With this approach, fundamental parameters governing the photoconverting performance can be systematically studied and optimized. Conventional monolayer-based photoconversion systems typically rely on the covalent linkage of thiol- or silane-functionalized photoactive conjugates on electrodes, which often require nontrivial synthesis in organic media. By contrast, our approach takes advantage of the versatile assembly of phospholipids in water and potentially provides an alternative approach to modular photoelectrochemical cell design.
On a more practical level, we're working on alternative photoconversion schemes using several molecular assembling strategies. To bring photoactivity into our systems, we have our hands on both natural (such as chlorophylls and carotenes) and synthetic dye species. On the synthetic side, fullerenes have been frequently included in building artificial photoconversion systems owing to their excellent photochemical properties, including their narrow HOMO-LUMO gap, long-lived photoinduced charge separation and low reorganization energy associated with the electron/energy transfer. Besides fullerenes, we’re also interested in integrating other novel photoactive agents, such as ruthenium tris(bipyridyl) complexes and porphyrins, into these molecular assemblies. Similar successes we’ve had so far clearly points to the generality and modularity of our assembling-based approach.
More details on the lastest development in this area can be found in our recent publications.
One of our long-term research goals is to develop integrated chemical systems for sensitive biorecognition and detection. While it seems increasingly easy to achieve high-sensitivity detection nowadays, it remains difficult to do it cheaply and reliably. Thus, we’ve spent a lot of time thinking about multiplexing and signal amplification.
Equally important in achieving sensitive and reliable biological/chemical detection is the mechanisms for signal generation and transduction. To this end, we’re working on new strategies for immobilization of biomaterials on electrodes so that inexpensive electrochemical readouts can be carried out at the end. Importantly, electrochemistry-based detection schemes also bear a great potential in simultaneous detection of multiple analytes. In this case, our experience in microfabrication and patterning comes in handy.
Our current research in materials chemistry focuses on lipid-assembled matrices and materials for biosensing and solar energy conversion. As a family of natural biomaterial, lipids can be either directly extracted from natural sources or synthesized from widely available starting materials. More importantly, lipids combine several appealing characteristics that make them ideal building blocks in constructing integrated chemical systems. For example, they are used by Nature to form cell membranes of all organisms, hosting molecular machineries including numerous cell receptors and photosynthesis system complexes. In addition, lipids can form stable microscopic colloid particles, such as liposomes, in solution and bilayer structure on solid support surfaces. These assembled structures can be further controlled in terms of size, bilayer thickness and fluidity. Further chemical modification to these lipids can be made with great flexibility so that structures with additional functionalities can be obtained. These new functional groups, in turn, provide additional means for bioimmobilization, the first step in building biosensors. Last but not least, the assembled acyl chains of lipids form a 2-dimensional oleophilic environment in which many hydrophobic molecules can be dissolved or inserted. This offers a completely different mechanism for integration and thus increases the overall complexity of the system. Please check out our recent publications in this area for more information.
27. Liu, L. et al. “Effects of Oriented Surface Dipole on Photoconversion Efficiency in an Alkane/Lipid-Hybrid-Bilayer-Based Photovoltaic Model System.” ChemPhysChem, 2013, 2777-2785.
26. Liu, L.; Zhan, W. “Molecular Photovoltaic System Based on Fullerenes and Carotenoids Co-Assembled in Lipid/Alkanethiol Hybrid Bilayers.” Langmuir, 2012, 4877-4882.
25. Xie, H.; Jiang, K.; Zhan, W. “A Modular Molecular Photovoltaic System Based on Phospholipid/Alkanethiol Hybrid Bilayers: Photocurrent Generation and Modulation.” Phys. Chem. Chem. Phys., 2011, 17712-17721.
24. Song, N.; Zhu, H.; Jin, S.; Zhan, W.; Lian, T. “Poisson-Distributed Electron-Transfer Dynamics from Single Quantum Dots to C60 Molecules.” ACS Nano, 2011, 613-621.
23. Zhan et al. “Photocurrent Generation from Porphyrin/Fullerene Complexes Assembled in a Tethered Lipid Bilayer.” Langmuir, 2010, 15671-15679.
22. Jiang, K.; Xie, H.; Zhan, W. “Photocurrent Generation from Ru(bpy)32+ Immobilized on Phospholipid/Alkanethiol Hybrid Bilayers.” Langmuir, 2009, 11129-11136.
21. Zhan, W.; Jiang, K. “A Modular Photocurrent Generation System Based on Phospholipid-Assembled Fullerenes.”Langmuir, 2008, 13258-13261.
20. Yu, Y.; Zhan, W.; Albrecht-Schmitt, T. E. “[H2bipy]2[(UO2)6Zn2(PO3OH)4(PO4)4]·H2O: An Open-Framework Uranyl Zinc Phosphate Templated by Diprotonated 4,4´-bipyridyl.” Inorg. Chem., 2008, 9050-9054.
19. Alsobrook, A. N.; Zhan, W.; Albrecht-Schmitt, T. E. “On the Use of Bifunctional Phosphonates for the Preparation of Heterobimetallic 5f-3d Systems.” Inorg. Chem., 2008, 5177-5183.
18. Nelson, A. G. D.; Bray, T. H.; Zhan, W.; Albrecht-Schmitt, T. E. “Further Examples of the Failure of Surrogates to Properly Model the Structural and Hydrothermal Chemistry of Transuranium Elements: Insights Provided by Uranium and Neptunium Diphosphonates.” Inorg. Chem., 2008, 4945-4951.
17. Jiang, K.; Zhang, H.; Shannon, C.; Zhan, W. “Preparation and Characterization of Polyoxometalate/ Protein Ultrathin Films Grown on Electrode Surfaces Using Layer-by-Layer Assembly.”Langmuir, 2008, 3584-3589.
16. Yu, Y.; Zhan, W.; Albrecht-Schmitt, T. E. “One- and Two-Dimensional Silver and Zinc Uranyl Phosphates Containing Bipyridyl Ligands.” Inorg. Chem., 2007, 10214-10220.
15. Zhan, D.; Li, X.; Zhan, W.; Fan, F.-R. F.; Bard, A. J. “Scanning Electrochemical Microscopy. 58. The Application of a Micropipette-Supported ITIES Tip to Detect Ag+ and Study Its Effect on Fibroblast Cells.” Anal. Chem. 2007, 5225-5231.
14. Zhan, W.; Bard, A. J. “Electrogenerated Chemiluminescence. 83. Immunoassay of Human C-Reactive Protein (CRP) by Using Ru(bpy)32+ Encapsulated Liposomes as Labels.”Anal. Chem., 2007, 459-463.
13. Bard, A. J.; Li, X.; Zhan, W. “Chemically Imaging Living Cells by Scanning Electrochemical Microscopy.” Biosens. Bioelect. 2006, 461-472.
12. Zhan, W.; Bard, A. J. “Scanning Electrochemical Microscopy. 56. Probing Outside and Inside Single Giant Liposomes Containing Ru(bpy)32+.”Anal. Chem., 2006, 726-733.
11. Zhan, W.; Crooks, R. M. “Microelectrochemical Logic Circuits.”J. Am. Chem. Soc., 2003, 9934-9935. (Highlighted by Chemical & Engineering News, Sep. 1 2003, Nature Materials Sep. 2003 and Analytical Chemistry Oct. 1 2003)
10. Zhan, W.; Alvarez, J.; Sun, L.; Crooks, R. M. “A Multichannel Microfluidic Sensor that Detects Anodic Redox Reactions Indirectly Using Anodic Electrogenerated Chemiluminescence.” Anal. Chem., 2003, 1233-1238.
9. Zhan, W.; Alvarez, J.; Crooks, R. M. “A Two-Channel Microfluidic Sensor that Uses Anodic Electrogenerated Chemiluminescence as a Photonic Reporter of Cathodic Redox Reactions.” Anal. Chem., 2003, 313-318.
8. Zhan, W.; Alvarez, J.; Crooks, R. M. “Electrochemical Sensing in Microfluidic Systems Using Electrogenerated Chemiluminescence as a Photonic Reporter of Electroactive Species.” J. Am. Chem. Soc., 2002, 13265-13270.
7. Zhan, W.; Seong, G. H.; Crooks, R. M. “Hydrogel-Based Microreactors as a Functional Component of Microfluidic Systems.” Anal. Chem., 2002, 4647-4652.
6. Seong, G. H.; Zhan, W.; Crooks, R. M. “Fabrication of Microchambers Defined by Photopolymerized Hydrogels and Weirs within Microfluidic Systems: Application to DNA Hybridization.” Anal. Chem., 2002, 3372-3377.
5. Zhan, W.; Wang, T.; Li, S. F. Y. “Derivatization, Extraction and Concentration of Amino Acids and Peptides by Using Organic/Aqueous Phases in Capillary Electrophoresis with Fluorescence Detection.” Electrophoresis, 2000, 3593-3599.
4. Zhan, W.; Xu, Y.; Li, A.; Zhang, J.; Schramm, K. M.; Kettrup, A. “Endocrine Disruption by Hexachlorobenzene in Crucian Carp (Carassius auratus gibelio).” B. Environ. Contam. Tox., 2000, 560-566.
3. Zhan, W.; Wang, T.; Li, S. F. Y. “Coupling of Solvent Semimicroextraction with Capillary Electrophoresis Using Ethyl Acetate as Sample Matrix.” Electrophoresis, 2000, 573-578.
2. Zhang, D. N.; Zhou, Z. P.; Tang, Y. Z.; Wu, C. Y.; Zhan, W.; Xu, Y. “Analysis of Organchlorine Compounds in Water by Solid Phase Microextraction and Gas Chromatography.” Chinese J. Anal. Chem., 1999, 768-772.
1. Zhang, D. N.; Zhou, Z. P.; Tang, Y. Z.; Wu, C. Y.; Zhan, W.; Xu, Y. “Sol-gel method for the preparation of solid-phase microextraction fibers.”Anal. Lett., 1999, 1675-1681.
Thanks for your visit!
I came to Auburn from Texas, where I spent six years receiving my Ph.D. and postdoctoral training. Before that, I grew up in a mid-size city in China and made up my mind early to become a chemist under the positive influence of my high-school chemistry teacher. Chemistry aside, I enjoy sports, music and reading.
Second-year graduate student.
Research interests: Artificial photosynthesis and lipid assemblies.
Hi! I'm Alex and I'm a junior chemistry student at Auburn. I'm pretty good at skateboarding and like to learn some solar energy related chemistry in Dr. Zhan's lab.
Hi! I'm Matt and I'm a junior chemistry student at Auburn. I'm working on hybrid lipid bilayers in Dr. Zhan's lab.
Postdoctoral researcher '07-'10, Current employment: Professor, Huangzhong University of Science and Technology, Wuhan, China
Visiting Scholar '10-'11, Current employment: Associate Professor, Wuhan University, Wuhan, China
Postdoctoral researcher '11-'12, Current employment: Postdoctoral researcher, Texas A&M
Ph.D. candidate '07-'12
Ph.D. candidate '08-'13
Undergraduate researcher '10-'12, Currently at: Medical school, UAB
Our research is currently supported by the National Science Foundation. We're grateful for their recognition and generous support.