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Xiyun (Richard) Guan

Xiyun (Richard) Guan, Ph.D.

Xiyun (Richard) Guan, Ph.D.
Associate Professor of Chemistry






388 Robert A. Pritzker Science Center


B.S. China University of Geosciences
M.S. Chinese Academy of Geological Sciences
Ph.D. University of Kentucky

Research & Accomplishments 

An aspect of my research is to develop nanopore technique for various applications in biotechnology at the single molecule level. The engineered nanopores 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.

In addition, we are also interested in the 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.


  • 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.


Guan, X.; de Zoysa, R. S.; Jayawardhana, D. A.; Zhao, Q. Stochastic detection of terrorist agents and biomolecules in a biological channel. In: Nanopores: Sensing and Fundamental Biological Interactions (R. Bashir and S. Iqbal, eds), Springer, 2011, 313-334 (ISBN: 978-1-4419-8251-3).


Y. Han, S. Zhou, L. Wang, and X. Guan. Nanopore back titration analysis of dipicolinic acid. Electrophoresis2015, 36, 467-470.

L. Wang, Y. Han, S. Zhou and X. Guan. Nanopore biosensor for label-free and real-time detection of anthrax lethal factor. ACS Appl. Mater. Interfaces, 2014, 6, 7334-9.

L. Wang, Y. Han, S. Zhou, and X. Guan. Real-time Label-free measurement of HIV-1 protease activity by nanopore analysis. Biosens Bioelectron. 2014, 62, 158-62.

G. Wang, L. Wang, Y. Han, S. Zhou and X. Guan. Nanopore stochastic detection: Diversity, sensitivity, and beyond. Acc. Chem. Res., 2013, 46, 2867-2877.

Wang, G.; Wang, L.; Han, Y.; Zhou, S.; Guan, X. Nanopore detection of copper ions using a polyhistidine probe. Biosens. Bioelectron. 2014, 53, 453-458.

Wang, G.; Zhao, Q.; Kang, X.; Guan, X. Probing mercury(ii)-DNA interactions by nanopore stochastic sensing. J. Phys. Chem. B. 2013, 117, 4763-4769.

Gupta, J.; Zhao, Q.; Wang, G.; Kang, X.; Guan, X. Simultaneous detection of CMPA and PMPA, hydrolytes of soman and cyclosarin nerve agents, by nanopore analysis. Sens. Actuators B Chem. 2013, 176, 625-631.

Krishantha, D. M. M.; Breitbach, Z. S.; Padivitage, N. L. T.; Armstrong, D. W.; Guan, X. Rapid determination of sample purity and composition by nanopore stochastic sensing. Nanoscale, 2011, 3, 4593-4596.

Jayawardhana, D. A.; Sengupta, M.; Krishantha, D. M. M.; Gupta, J.; Armstrong, D. W.; Guan, X. A chemical-induced and pH-mediated molecular switch. Anal. Chem., 2011, 83, 7692-7697.

Liu, A.; Zhao, Q.; Krishantha, D. M. M.; Guan, X. Unzipping of double-stranded DNA in engineered protein pores. J. Phys. Chem. Lett., 2011, 2, 1372–1376.

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.

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.

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.

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

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

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.