Conductive Probe Atomic Force Microscopy in an Electrochemical Environment: A Tool to Study Force Interactions, Charge Transport and Reactivity at the (Bio-)Nanoscale

• Research unit: COST
• Project number: C12.0074

Key words (English)

conductive probe AFM; electrochemistry; charge tranfer; proteins; geobacter; force spectroscopy

Research programs (English)

COST-Action TD1002 - European network on applications of Atomic Force Microscopy to NanoMedicine and Life Sciences

Short description (English)

This project focuses on the development of atomic force microscopy with conductive probes (CPAFM) in an electrolyte environment, i.e. under electrochemical and/or physiological conditions, and application of this technique for the studies of structure and reactivity (electron transfer) in biological systems. To achieve this goal, we combine our experience in (nano-)electrochemistry and the application of scanning probe methods under electrochemical conditions with the experience partners within the of COST TD1002 consortium on the fabrication of multifunctional AFM probes and on surface-immobilization as well as AFM studies (imaging and force spectroscopy) of biological samples. With this novel analytical technique we aim at addressing charge transfer and force interaction between a conductive (modified) AFM probe and surface-immobilized single (bio)molecules (horse heart cytochrome, azurin) as well as active surface sites of Fe(III)-reducing bacteria Geobacter sulfurreducens in whole cell studies under physiological conditions.

Further information (English)

Full name of research-institution/enterprise: Universität Bern Departement für Chemie und Biochemie

Partners and International Organizations (English)

AT; BE; HR; DK; FI; FR; DE; EL; HU; IE; IL; IT; LT; LU; NL; NO; PL; PT; RO; RS; ES; CH; TU; UK

Abstract (English)

The technique of conductive-probe atomic force microscopy (CPAFM) under electrochemical conditions allows measuring electron and ion currents in an electrolyte environment, i.e. under electrochemical and/or physiological conditions (Nanotechnology 24 (2013) 115501). In this project, we developed insulated conductive AFM probes and optimized procedures for the insulation of probes mounted in an AFM setup. The potential of the electrochemical CPAFM approach was demonstrated in explorative studies. We employed current-sensing force spectroscopy technique to characterize the electric and mechanical properties of gold atomic (J. Phys. Chem. Lett. 5 (2014) 3560) and gold-molecule-gold (Sci. Rep. 5 (2015) 9002) junctions and demonstrated a strong correlation of these properties with the junction geometry. Electrochemical control of a non-covalent binding between a redox-active ferrocene moiety and ß-cyclodextrin was demonstrated by force spectroscopy experiments under electrochemical conditions (Chem. Comm. 50 (2014) 11757). The assembly of electrogenic bacteria Geobacter sulfurreducens on gold was explored in electrochemical and AFM imaging experiments. Further research topics emerging on the interface between electrochemistry and scanning probe techniques were addressed.

References in databases (English)

Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. [phone] Swiss Project-Number: C12.0074