title: Tracking live cell response to cadmium (II) concentrations by scanning electrochemical microscopy.
abstract: The biological chemistry of toxic heavy metals, such as Cd (II), has become an active area of research due to connections with increased oxidative stress, cytotoxicity, and human/animal carcinogenicity. In this study, scanning electrochemical microscopy (SECM) was used as a noninvasive technique to monitor membrane permeability of single live human bladder cancer cells (T24) subjected to exposure of Cd (II) at various concentrations. The addition of a membrane permeable redox mediator, ferrocenemethanol (FcMeOH), in combination with depth scan imaging provided probe approach curves (PACs) to reveal changes in membrane homeostasis. To demonstrate the strength of SECM as a bioanalytical technique for cell physiology and pathology, we tested responses of live cells after 1h incubations with various concentrations of Cd (II). For the first time, a trend in membrane permeability of Cd (II) treated live T24 cells was discovered. Dependent on the incubation concentration, the trend displayed an initial decrease in membrane permeability coefficient from 75μm/s for control cells to 25μm/s for cells incubated with 75μM Cd (II). This was followed by an eventual return to the permeability coefficient of control cells (75μm/s) with further increases in Cd (II) exposure. The cells were found to respond at as little as 10μM Cd (II) concentrations. This work further demonstrates the use of SECM as a bioanalytical technique to monitor cell physiology and topography. A greater insight into the complex mechanisms behind Cd (II) toxicity is anticipated.
authors.affiliation: Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Henderson
authors.affiliation: Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada.
authors.forename: Fraser P
authors.initials: FP
authors.lastname: Filice
authors.affiliation: Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada.
authors.forename: Michelle S M
authors.initials: MSM
authors.lastname: Li
authors.affiliation: Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada. Electronic address: zfding@uwo.ca.
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Ding
mesh_terms: D002104:Cadmium / Q000633:toxicity*; D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability / Q000187:drug effects*; D006801:Humans; D008853:Microscopy; D064347:Microscopy, Electrochemical, Scanning / Q000379:methods*; D001749:Urinary Bladder Neoplasms / Q000378:metabolism
chemical_list: D002104:Cadmium
keywords: Cadmium toxicity; Depth scan; Membrane permeability; Probe approach curve; Scanning electrochemical microscopy; Single live cell