Non-destructive Patterning of Carbon Electrodes by Using the Direct Mode of Scanning Electrochemical Microscopy.

Patterning of glassy carbon surfaces grafted with a layer of nitrophenyl moieties was achieved by using the direct mode of scanning electrochemical microscopy (SECM) to locally reduce the nitro groups to hydroxylamine and amino functionalities. SECM and atomic force microscopy (AFM) revealed that potentiostatic pulses applied to the working electrode lead to local destruction of the glassy carbon surface, most likely caused by etchants generated at the positioned SECM tip used as the counter electrode. By applying galvanostatic pulses, and thus, limiting the current during structuring, corrosion of the carbon surface was substantially suppressed.

A chemical lift-off process: removing non-specific adsorption in an electrochemical Epstein-Barr virus immunoassay.

Upon contact of sensor surfaces with complex biological samples containing a variety of different proteins, non-specific adsorption hampers the high-sensitive detection of the analyte in question. To substantially decrease the impact of non-specific adsorption at thiol-based self-assembled monolayers, a chemical lift-off process is introduced. A sequence of local hydrolysis of isooctyl 3-mercaptopropionate, covalent binding of an antigen against the Epstein-Barr virus (EBV), stepwise incubation with a serum sample possibly containing the EBV antibody and an enzyme-labeled anti-human antibody is completed with a lift-off by integral hydrolysis of the remaining ester groups at the self-assembled monolayer.

Imaging biocatalytic activity of enzyme-polymer spots by means of combined scanning electrochemical microscopy/electrogenerated chemiluminescence.

The purpose of this study was to develop a scanning electrochemical microscopy (SECM) and scanning electrogenerated chemiluminescence (SECL) setup to visualize the localized enzymatic activity using glucose oxidase as a model. Combination of SECM and electrogenerated chemiluminescence (ECL) was made possible by integrating a photomultiplier tube (PMT) within a SECM setup which is mounted on top of an inverted microscope. An enzyme-polymer spot formed on a glass slide and placed on top of the entrance window of the PMT was used as a model sample to evaluate the potential of the combined SECM/ECL setup.