NANO LETTERS
Quantitative Nanoscale Dielectric Microscopy of Single-Layer Supported Biomembranes
2009 Vol. 9, No. 4 1604-1608
Laura Fumagalli,*,† Giorgio Ferrari,‡ Marco Sampietro,‡ and Gabriel Gomila*,† Institut de Bioenginyeria de Catalunya (IBEC) and Departament d’Electro`nica, UniVersitat de Barcelona, C/ Martı´ i Franque`s 1, 08028 Barcelona, Spain, and Dipartimento di Elettronica e Informazione, Politecnico di Milano, P.za Leonardo da Vinci 32, I-20133 Milano, Italy Received December 19, 2008; Revised Manuscript Received February 19, 2009
ABSTRACT We present the experimental demonstration of low-frequency dielectric constant imaging of single-layer supported biomembranes at the nanoscale. The dielectric constant image has been quantitatively reconstructed by combining the thickness and local capacitance obtained using a scanning force microscope equipped with a sub-attofarad low-frequency capacitance detector. This work opens new possibilities for studying bioelectric phenomena and the dielectric properties of biological membranes at the nanoscale.
The dielectric constant of membranes is an important parameter of cell bioelectricity as it quantifies the intrinsic dielectric behavior of the plasma membrane in the lowfrequency domain (
