Quantitative Nanoscale Dielectric Microscopy of Single-Layer Supported Biomembranes

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.

Nanoscale dielectric microscopy of non-planar samples by lift-mode electrostatic force microscopy

“…Among them, we can cite nanoscale capacitance microscopy [1][2][3], electrostatic force microscopy (EFM) [4][5][6][7][8][9][10], nanoscale impedance microscopy [11,12], scanning polarization force microscopy [13][14][15][16], scanning microwave microscopy (SMM) [17,18] and nanoscale non-linear dielectric microscopy [19]. These techniques have allowed measuring the electric permittivity with nanoscale spatial resolution on planar samples, such as thin oxides, polymer films and supported biomembranes [2][3][4]8,10], and on non-planar ones, such as, single carbon nanotubes, nanowires, nanoparticles, viruses and bacterial cells [20][21][22][23][24][25][26][27][28][29][30].…”

Imaging dielectric relaxation in nanostructured polymers by frequency modulation electrostatic force microscopy

“…Schwartz,4 A. Alegria, 2 Ph. Tordjeman, 5 We have developed a method for imaging the temperature-frequency dependence of the dynamics of nanostructured polymer films with spatial resolution.…”

“…3 Concerning local dielectric characterization, on the one hand, various atomic force microscopy based methods have been developed to image the dc dielectric constant at nanoscale. Fumagalli et al 4 have developed the so-called "nanoscale capacitance microscopy," where the microscope is equipped with a subattofarad low-frequency capacitance detector. The same group also proposed a method based on the detection of the dc electrostatic force to image the dielectric constant of a purple membrane patch.…”

Band excitation Kelvin probe force microscopy utilizing photothermal excitation

“…KPFM has been particularly useful for characterizing materials and devices ranging from metals, 1 semiconductors, 8,9 and ferroelectrics, 10,11 to self-assembled monolayers, 12 polymers, 13 and biomolecules. 14,15 The continued success of KPFM necessitates both the advancement of the technique in terms of accuracy and resolution 16,17 across all imaging environments, 18,19 as well as improved capabilities to distinguish and correlate different electronic parameters (i.e., dielectric properties, [20][21][22][23] dissipation 24,25 ) beyond that currently attainable with conventional KPFM.…”

“…Although FM-KPFM leads to higher lateral resolution, it is also known to suffer from decreased bias sensitivity compared to AM-KPFM and requires large V ac , which can be problematic when characterizing voltage-sensitive materials. 38 Noteworthy, closed loop KPFM techniques only provide a single parameter map of the V cpd , whereas further information on local dielectric properties [20][21][22][23] or electronic dissipation 24,25 is attainable using open loop (OL) electrostatic force microscopy (EFM). Recently, BE-KPFM has shown promise in capturing information beyond what is obtainable using conventional KPFM and or EFM alone.…”