Department of Chemistry and Biochemistry

Single molecule detection Biomaterial development for use in sensors Direct and in-situ environmental monitoring and medical diagnosis Single Molecule Detection An aspect of my research is to use protein nano-pore technique for applications in biotechnology at the single molecule level. The engineered protein nano-pores have a variety of new functional properties that could be used as a basis for making sensors. Since the data obtained are not obscured by the average values that are inherent in conventional chemical and biochemical experiments, single-molecule detection provides information about the distribution and time trajectories that would otherwise be hidden by the statistical mean. We are especially interested in the development of biosensors for bio-terrorist/bio-defense chemicals, environmental pollutants, toxins, DNA and protein molecules. Biomaterial development for use in sensors The design and synthesis of biomaterials is a rapidly growing interdisciplinary area, in which the properties of molecules found in nature are mimicked or extended to produce materials with new functional properties. We are interested in engineering nanotubes with a variety of novel functions, and using the functionalized nanotubes as an alternative to current protein-based single molecule stochastic sensing technique. Furthermore, the development of functionalized artificial nanopore would be another interesting research topic. Direct and in-situ environmental monitoring and medical diagnosis One of the greatest challenges of the development of biosensor technology is its practical application. Most of the current biosensor techniques still focus on detecting analytes in pure water or low matrix samples, which restricts its usage to the laboratory research only. We are interested in moving biosensors out of the laboratory and into commercial applications, for example, to develop sensing techniques that could be employed in the analysis of environmental and biological samples, and for the application in field detection.

Xia, D.; Guan, X.; Huang, H. Catalytic wave of tungsten-salicylfluorone complex. Rock and Mineral Analysis, 1991, 10, 185-188.

Xia, D.; Guan, X.; Huang, H. Study on the catalytic wave of the tungsten-bromopyrogallol red complex. Anal. Lab, 1992, 11, 35-37.

Sun, Y.; Guan, X.; Du, A. Preconcentration of precious metals by nickel sulfide fire assay. I. Determination of platinum group elements in geological samples by ICP-MS. Rock and Mineral Analysis, 1997, 16, 12-17.

Sun, Y.; Guan, X.; Du, A. Determination of platinum group elements by inductively coupled plasma-mass spectrometry combined with nickel sulfide fire assay and tellurium coprecipitation. Spectrochim. Acta, Part B 1998, 53B, 1463-1467.

Ramanathan, S.; Shetty, R. S.; Guan, X.; Daunert, S. Luminescence based sensing systems employing genetically engineered bacteria. In: Proceedings of the 10th. International Symposium on Bioluminescence and Chemiluminescence (A. Roda, L. Kricka, and P. Stanley, eds), John Wiley & Sons: Chichester, England, 1999, 601-604.

Gao, H.; Qu, W.; Du, A.; Guan, X.; Sun, Y.; Zhao, Y.; Zhang, Y. Low blank nickel sulfide fire assay preconcentration of platinum group elements in geochemical standard samples for neutron activation analysis. Chinese J. Anal. Chem. 1999, 27, 566-569.

Guan, X.; Li, Y. Application research on surfactant-kinetic spectrophotometric determination of trace selenium and tellurium. Rock and Mineral Analysis, 2000, 19, 14-19.

Guan, X.; Ramanathan, S.; Garris, J. P.; Shetty, R. S.; Ensor, M.; Bachas, L. G.; Daunert, S. Chlorocatechol detection based on a clc operon/reporter gene system. Anal. Chem. 2000, 72, 2423-2427.

Guan, X.; D’Angelo, E.; Luo, W.; Daunert, S. Whole-cell biosensing of 3-chlorocatechol in liquids and soils. Anal. Bioanal. Chem. 2002, 374, 841-847.

Guan, X.; Gu, L. Q.; Cheley, S.; Braha, O.; Bayley, H. Stochastic sensing of TNT with a genetically engineered pore. ChemBioChem, 2005, 6, 1875-1881.

Kang, X. F.; Cheley, S.; Guan, X.; Bayley, H. Stochastic detection of enantiomers. J. Am. Chem. Soc. 2006, 128, 10684-10685.

Feliciano, J.; Xu, S.; Guan, X.; Lehmler, H. J.; Bachas, L. G.; Daunert, S. ClcR-based biosensing system in the detection of cis-dihydroxylated (chloro-)biphenyls. Anal. Bioanal. Chem. 2006, 385, 807-813.

Zhao, Q.; Jayawardhana, D. A.; Guan, X. Stochastic study of the effect of ionic strength on non-covalent interactions in protein pores. Biophys. J. 2008, 94, 1267-1275.

Zhao, Q.; Wang, D.; Jayawardhana, D. A.; Guan, X. Stochastic sensing of biomolecules in a nanopore sensor array. Nanotechnology 2008, 19, 505504.

Jayawardhana, D. A.; Crank, J. A.; Zhao, Q.; Armstrong, D. W.; Guan X. Nanopore stochastic detection of a liquid explosive component and sensitizers using boromycin and an ionic liquid supporting electrolyte. Anal. Chem. 2009, 81, 460-464.

Zhao, Q.; Jayawardhana, D. A.; Wang, D.; Guan, X. Study of peptide transport through engineered protein channels. J. Phys. Chem. B 2009, 113, 3572-3578.

Wang, D.; Zhao, Q.; de Zoysa, R. S.; Guan, X. Detection of nerve agent hydrolytes in an engineered nanopore. Sens. Actuators B Chem. 2009, 139, 440-446.

Zhao, Q.; Wang, D.; Jayawardhana, D. A.; de Zoysa, R. S.; Guan, X. Real-time monitoring of peptide cleavage using a nanopore probe. J. Am. Chem. Soc. 2009, 131, 6324-6325.

de Zoysa, R. S.; Jayawardhana, D. A.; Zhao, Q.; Wang, D.; Armstrong, D. W.; Guan, X. Slowing DNA translocation through nanopores using a solution containing organic salts. J. Phys. Chem. B 2009, 113, 13332-13336.

Guan, X.; Gupta, J.; Zhao, Q.; de Zoysa, R. S.; Jayawardhana, D. A. Nanopore detection of nerve agent degradation products. In: Proceedings of Nanotech conference & Expo 2010, Taylor & Francis: New York, NY, 2010, vol. 2, 99-102.

Zhao, Q.; Jayawardhana, D. A.; Guan, X. Apparatus and system for pattern recognition sensing for biomolecules. U.S. Pat. Appl. Publ. (2010), US 2010099198 A1.

Guan, X.; Jayawardhana, D. A.; Armstrong, D. W.; de Zoysa, R. S.; Wang, D.; Zhao, Q. Genomic sequencing using modified protein pores and ionic liquids. PCT Int. Appl. (2010), WO 2010062903 A2.

Liu, A.; Zhao, Q.; Guan, X. Stochastic nanopore sensors for the detection of terrorist agents: current status and challenges. (Anal. Chim. Acta, in press, DOI: 10.1016/j.aca.2010.07.001)

B.S. China University of Geosciences, P. R. China (1990)

M.S. Chinese Academy of Geological Sciences, P. R. China (1995)

Ph.D. University of Kentucky (2002)

Postdoctoral Fellow: Texas A&M University (2002-2005)

Xiyun (Richard) Guan is Assistant Professor in the Department of Chemistry and Biochemistry at the University of Texas at Arlington (UTA). Richard received his B.S. degree in Chemistry in 1990 from China University of Geosciences, his M.S. degree in Chemistry in 1995 from Chinese Academy of Geological Sciences, and later his Ph.D. degree in Chemistry from University of Kentucky in 2002 under the supervision of Profs. Sylvia Daunert and Leonidas G. Bachas. He performed post-doctoral research in the laboratory of Prof. Hagan Bayley in the Department of Medical Biochemistry and Genetics at Texas A&M University. Since joining UTA in 2005, his research has been focused on the use of protein nanopore technique for applications in biotechnology at the single molecule level. Financial support for his group’s research is from UTA, Defense Advanced Research Projects Agency, Department of Homeland Security, the National Institutes of Health, and the National Science Foundation.

College of Science Research Excellence Awards, UT-Arlington, 2008, 2009

TORA scholarship, University of Kentucky (2000)

Science and Technology Advance Award, Chinese Ministry of Geology and Mineral Resources, P. R. China (1996)

Alumni Foundation Award, China University of Geosciences (1994)

Employee of the Year Award, Regional Research Center of South JiangXi (1991)

Student of the Year Award, China University of Geological Sciences (1986-1990)

Second Place in Physics Competition, China University of Geological Sciences (1987)