title: Immunosensor for the ultrasensitive and quantitative detection of bladder cancer in point of care testing.
abstract: An ultrasensitive and real-time impedance based immunosensor has been fabricated for the quantitative detection of Galectin-1 (Gal-1) protein, a biomarker for the onset of multiple oncological conditions, especially bladder cancer. The chip consists of a gold annular interdigitated microelectrode array (3×3 format with a sensing area of 200µm) patterned using standard microfabrication processes, with the ability to electrically address each electrode individually. To improve sensitivity and immobilization efficiency, we have utilized nanoprobes (Gal-1 antibodies conjugated to alumina nanoparticles through silane modification) that are trapped on the microelectrode surface using programmable dielectrophoretic manipulations. The limit of detection of the immunosensor for Gal-1 protein is 0.0078mg/ml of T24 (Grade III) cell lysate in phosphate buffered saline, artificial urine and human urine samples. The normalized impedance variations show a linear dependence on the concentration of cell lysate present while specificity is demonstrated by comparing the immunosensor response for two different grades of bladder cancer cell lysates. We have also designed a portable impedance analyzing device to connect the immunosensor for regular checkup in point of care testing with the ability to transfer data over the internet using a personal computer. We believe that this diagnostic system would allow for improved public health monitoring and aid in early cancer diagnosis.
authors.affiliation: Department of Mechanical Engineering, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan. Electronic address: chchuang@mail.stust.edu.tw.
authors.forename: Cheng-Hsin
authors.initials: CH
authors.lastname: Chuang
authors.affiliation: Department of Electrical Engineering, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan.
authors.forename: Yi-Chun
authors.initials: YC
authors.lastname: Du
authors.affiliation: Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan.
authors.forename: Ting-Feng
authors.initials: TF
authors.lastname: Wu
authors.affiliation: Department of Chemistry and Material Engineering, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan.
authors.forename: Cheng-Ho
authors.initials: CH
authors.lastname: Chen
authors.affiliation: Department of Electronic Engineering, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan.
authors.forename: Da-Huei
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Department of Mechanical Engineering, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan.
authors.forename: Shih-Min
authors.initials: SM
authors.lastname: Chen
authors.affiliation: Department of Mechanical Engineering, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan.
authors.forename: Ting-Chi
authors.initials: TC
authors.lastname: Huang
authors.affiliation: Department of Mechanical Engineering, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan.
authors.forename: Hsun-Pei
authors.initials: HP
authors.lastname: Wu
authors.affiliation: Department of Mechanical Engineering, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan.
authors.forename: Muhammad Omar
authors.initials: MO
authors.lastname: Shaikh
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D055910:Antibodies, Immobilized / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation*; D045744:Cell Line, Tumor; D017097:Electric Impedance; D004867:Equipment Design; D037483:Galectin 1 / Q000652:urine*; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation; D057230:Limit of Detection; D008839:Microelectrodes; D053758:Nanoparticles / Q000737:chemistry; D000067716:Point-of-Care Testing; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis / Q000652:urine*
chemical_list: D055910:Antibodies, Immobilized; D037483:Galectin 1; D000537:Aluminum Oxide
keywords: Dielectrophoresis; Immunosensor; Impedance; Microelectrodes; Point of care