title: Surface Charge Visualization at Viable Living Cells.
abstract: Scanning ion conductance microscopy (SICM) is demonstrated to be a powerful technique for quantitative nanoscale surface charge mapping of living cells. Utilizing a bias modulated (BM) scheme, in which the potential between a quasi-reference counter electrode (QRCE) in an electrolyte-filled nanopipette and a QRCE in bulk solution is modulated, it is shown that both the cell topography and the surface charge present at cellular interfaces can be measured simultaneously at high spatial resolution with dynamic potential measurements. Surface charge is elucidated by probing the properties of the diffuse double layer (DDL) at the cellular interface, and the technique is sensitive at both low-ionic strength and under typical physiological (high-ionic strength) conditions. The combination of experiments that incorporate pixel-level self-referencing (calibration) with a robust theoretical model allows for the analysis of local surface charge variations across cellular interfaces, as demonstrated on two important living systems. First, charge mapping at Zea mays root hairs shows that there is a high negative surface charge at the tip of the cell. Second, it is shown that there are distinct surface charge distributions across the surface of human adipocyte cells, whose role is the storage and regulation of lipids in mammalian systems. These are new features, not previously recognized, and their implications for the functioning of these cells are highlighted.
authors: Department of Chemistry, ‡MOAC Doctoral Training Centre, §Division of Metabolic and Vascular Health, Warwick Medical School, and ∥School of Life Sciences, University of Warwick , Coventry CV4 7AL, United Kingdom.
authors: David
authors: D
authors: Perry
authors: Department of Chemistry, ‡MOAC Doctoral Training Centre, §Division of Metabolic and Vascular Health, Warwick Medical School, and ∥School of Life Sciences, University of Warwick , Coventry CV4 7AL, United Kingdom.
authors: Binoy
authors: B
authors: Paulose Nadappuram
authors: Department of Chemistry, ‡MOAC Doctoral Training Centre, §Division of Metabolic and Vascular Health, Warwick Medical School, and ∥School of Life Sciences, University of Warwick , Coventry CV4 7AL, United Kingdom.
authors: Dmitry
authors: D
authors: Momotenko
authors: Department of Chemistry, ‡MOAC Doctoral Training Centre, §Division of Metabolic and Vascular Health, Warwick Medical School, and ∥School of Life Sciences, University of Warwick , Coventry CV4 7AL, United Kingdom.
authors: Philip D
authors: PD
authors: Voyias
authors: Department of Chemistry, ‡MOAC Doctoral Training Centre, §Division of Metabolic and Vascular Health, Warwick Medical School, and ∥School of Life Sciences, University of Warwick , Coventry CV4 7AL, United Kingdom.
authors: Ashley
authors: A
authors: Page
authors: Department of Chemistry, ‡MOAC Doctoral Training Centre, §Division of Metabolic and Vascular Health, Warwick Medical School, and ∥School of Life Sciences, University of Warwick , Coventry CV4 7AL, United Kingdom.
authors: Gyanendra
authors: G
authors: Tripathi
authors: Department of Chemistry, ‡MOAC Doctoral Training Centre, §Division of Metabolic and Vascular Health, Warwick Medical School, and ∥School of Life Sciences, University of Warwick , Coventry CV4 7AL, United Kingdom.
authors: Bruno G
authors: BG
authors: Frenguelli
authors: Department of Chemistry, ‡MOAC Doctoral Training Centre, §Division of Metabolic and Vascular Health, Warwick Medical School, and ∥School of Life Sciences, University of Warwick , Coventry CV4 7AL, United Kingdom.
authors: Patrick R
authors: PR
authors: Unwin
mesh_terms: D002462:Cell Membrane / Q000502:physiology; D020527:Microscopy, Scanning Probe / Q000379:methods*; D009994:Osmolar Concentration; D018517:Plant Roots / Q000166:cytology; D013499:Surface Properties; D003313:Zea mays / Q000166:cytology*