Luxi Swisher
Department of Chemistry
Kansas State University, Manhattan, KS, 66506, U.S.A.
Email: [email protected] Phone: (785)-341-2195
Education Background
Sep.2006—June.2010 Chemistry Department, Northwest University, P. R. China
B. A.
Aug. 2010—Present Department of Chemistry, Kansas State University, U.S.A
Ph.D. Student
Research Experience
Sep.2008—June.2010 Participate in project “Investigation of the new multi-functional ligands and the structure-properties relationship of the coordination polymers” (National Natural Science Foundation)
Dec.2010—Present Join in project “Real-time electrochemical monitoring of cancerous protease (legumain) activity using nanoelectrode array” from Dr. Li’s group in K-State University
Research Insterest
Electrochemistry, nanotechnology, nanomaterials, biosensors
Current Research
Legumain (also known as asparaginyl endopeptidase) is a lysosomal cysteine protease which is found highly expressed in a majority of tumors including carcinomas of the breast, colon and prostate. However, overexpression is not found in normal cells, which makes it a potential cancer biomarker. Ferrocene (Fc) labeled peptides (NH2-(CH2)5-Ala-Ala-Asn-Leu-Fc) are end-grafted onto embedded vertically aligned carbon nanofiber (VACNF) nanoelectrode array (NEA) via a C5 linker, and their ability to act as substrates for legumain is investigated by real-time alternating current voltammetry (ACV). Fc is used as an electroactive reporter and the peptide as a recognition and cleavage site of legumain. The cleavage results in the release of Fc moieties from the electrode to the bulk solution, thus leading to a decrease of the ACV signal whose rate depends on the activity of legumain. The optimization on ACV conditions for legumain detection was carried out by careful investigation of electron transfer rates (ETRs) with ACV in comparison with direct current voltammetry (DCV) on Fc-functionalized CNF NEAs. Unique conical graphitic stacking of the CNFs was found to play a critical role in facilitating a new capacitive pathway in high-frequency ACV measurements, leading to 100 times higher ETRs than that measured by DCV. This indicates that the intrinsic limit of nanoelectrode materials can be solved by selecting an appropriate electrochemical technique. Particularly, high-frequency ACV detection using CNF NEAs can provide high-performance nano-biosensors for ultrasensitive detection of legumain activities in various cancerous cell lines with a simple portable electrochemical system.
Publication
“Temperature-Controlled 1D Helical and Discrete Coordination Complexes Based on Benzimidazole-5,6-dicarboxylic Acid”
Lu-Xi Zhang, Chang-Jun Fan, Ping Liu*, Guo-Ping Yang, Chen Ren, Rui-Ting Liu, Inorg.Chem.Commun., 13(8), 914-918, 2010
Department of Chemistry
Kansas State University, Manhattan, KS, 66506, U.S.A.
Email: [email protected] Phone: (785)-341-2195
Education Background
Sep.2006—June.2010 Chemistry Department, Northwest University, P. R. China
B. A.
Aug. 2010—Present Department of Chemistry, Kansas State University, U.S.A
Ph.D. Student
Research Experience
Sep.2008—June.2010 Participate in project “Investigation of the new multi-functional ligands and the structure-properties relationship of the coordination polymers” (National Natural Science Foundation)
Dec.2010—Present Join in project “Real-time electrochemical monitoring of cancerous protease (legumain) activity using nanoelectrode array” from Dr. Li’s group in K-State University
Research Insterest
Electrochemistry, nanotechnology, nanomaterials, biosensors
Current Research
Legumain (also known as asparaginyl endopeptidase) is a lysosomal cysteine protease which is found highly expressed in a majority of tumors including carcinomas of the breast, colon and prostate. However, overexpression is not found in normal cells, which makes it a potential cancer biomarker. Ferrocene (Fc) labeled peptides (NH2-(CH2)5-Ala-Ala-Asn-Leu-Fc) are end-grafted onto embedded vertically aligned carbon nanofiber (VACNF) nanoelectrode array (NEA) via a C5 linker, and their ability to act as substrates for legumain is investigated by real-time alternating current voltammetry (ACV). Fc is used as an electroactive reporter and the peptide as a recognition and cleavage site of legumain. The cleavage results in the release of Fc moieties from the electrode to the bulk solution, thus leading to a decrease of the ACV signal whose rate depends on the activity of legumain. The optimization on ACV conditions for legumain detection was carried out by careful investigation of electron transfer rates (ETRs) with ACV in comparison with direct current voltammetry (DCV) on Fc-functionalized CNF NEAs. Unique conical graphitic stacking of the CNFs was found to play a critical role in facilitating a new capacitive pathway in high-frequency ACV measurements, leading to 100 times higher ETRs than that measured by DCV. This indicates that the intrinsic limit of nanoelectrode materials can be solved by selecting an appropriate electrochemical technique. Particularly, high-frequency ACV detection using CNF NEAs can provide high-performance nano-biosensors for ultrasensitive detection of legumain activities in various cancerous cell lines with a simple portable electrochemical system.
Publication
“Temperature-Controlled 1D Helical and Discrete Coordination Complexes Based on Benzimidazole-5,6-dicarboxylic Acid”
Lu-Xi Zhang, Chang-Jun Fan, Ping Liu*, Guo-Ping Yang, Chen Ren, Rui-Ting Liu, Inorg.Chem.Commun., 13(8), 914-918, 2010