Faculty Research
Alphabetical · By research area

A major area of research in our group is on chemical speciation of trace elements. Our primary interest is on the speciation of metalloids (such as arsenic, antimony, and selenium) and metals (such as mercury, lead, cadmium, and vanadium), in view of their important impact on the environment and on human health. We develop chromatography and mass spectrometry techniques for the speciation analysis of trace elements in environmental, biochemical, and toxicological studies. These techniques enable the identification of metabolites and their interaction with proteins, improving the understanding of mechanisms of action. We are also interested in developing biomarkers to assess human exposure and to study metabolism and health effects of trace element species.

Another broad area of research involves the development of highly sensitive bioanalytical techniques for studying DNA damage and proteins. DNA damage and its cellular repair are key determinants in the early stages of carcinogenesis, cancer therapy, and aging. Studying DNA damage and repair requires sensitive assays for DNA damage. We develop techniques that combine affinity recognition, capillary electrophoresis, and laser-induced fluorescence polarization. These techniques are applied to the analysis of minute amounts of DNA damage caused by radiation and chemical carcinogens and to the studies of cellular repair of DNA damage. We further develop techniques that take advantages of DNA-protein binding, nano-material assembly, and polymerase amplification. These techniques are applied to studies of protein biomarkers, natural toxins, therapeutic drugs, environmental contaminants, and DNA-protein interactions.

The research group is well equipped with various atomic spectrometry, mass spectrometry, capillary electrophoresis, laser-induced fluorescence, fluorescence polarization, liquid chromatography, and cellular and molecular biology facilities. The group is composed of multidisciplinary researchers and enjoys collaboration with biochemists, toxicologists and clinicians.

Dr. Le is an elected Fellow of Royal Society of Canada, Academy of Science. He is the Canada Research Chair in Bioanalytical Technology and Environmental Health.

Selected Publications

Wang, H.; Lu, M.; Tang, M.-S.; Van Houten, B.; Ross, J.B.A.; Weinfeld, M.; Le, X.C. DNA wrapping is required for DNA damage recognition in the E. coli DNA nucleotide excision repair pathway. Proc. Natl. Acad. Sci. USA 106, 12849–12854 (2009).

Qin, J.; Lehr, C.R.; Yuan, C.; Le, X.C.; McDermott, T.R.; Rosen, B.P. Biotransformation of arsenic by a Yellowstone thermoacidophilic eukaryotic alga. Proc. Natl. Acad. Sci. USA 106, 5213–5217 (2009).

Yan, H.; Wang, N.; Weinfeld, M.; Cullen, W.R.; Le, X.C. Identification of arsenic-binding proteins in human cells by affinity chromatography and mass spectrometry. Anal. Chem. 81, 4144-4152 (2009).

Zhao, Q.; Lu, X.; Yuan, C.; Li, X.-F.; Le, X.C. Aptamer-linked assay for thrombin using gold nanoparticle amplification and inductively coupled plasma mass spectrometry detection. Anal. Chem. 81, 7484-7489 (2009).

Zhang, H.; Li, X.-F.; Le, X.C. Differentiation and detection of PDGF isomers and their receptors by tunable aptamer capillary electrophoresis. Anal. Chem. 81, 7795–7800 (2009).

Charoensuk, V.; Gati, W.; Weinfeld, M.; Le, X.C. Differential cytotoxic effects of arsenic compounds in human acute promyelocytic leukemia cells. Toxicol. Appl. Pharmacol. 239, 64-70 (2009).

Shen, S.; Lee, J; Cullen, W.R.; Le, X.C.; Weinfeld, M. Arsenite and its mono- and di-methylated trivalent metabolites enhance the formation of BPDE-DNA adducts in Xeroderma pigmentosum complementation group A cells. Chem. Res. Toxicol. 22, 382–390 (2009).

Li, F.; Zhao, Q.; Wang, C.; Lu, X.; Li, X.-F.; Le, X.C. Detection of E. coli O157: H7 using gold nanoparticle labelling and inductively coupled plasma-mass spectrometry. Anal. Chem. 82, 3399–3403 (2010).

Lew, K.; Acker, J.A.; Gabos, S.; Le, X.C. Biomonitoring of arsenic in urine and saliva of children playing on playgrounds constructed from chromated copper arsenate-treated wood. Environ. Sci. Technol. 44, 3986-3991 (2010).

McKnight-Whitford, A.; Chen, B.; Naranmandura, H.; Zhu, C.; Le, X.C. New method and detection of high concentrations of monomethylarsonous acid detected in contaminated groundwater. Environ. Sci. Technol. 44, 5875-5880 (2010).