Detection of reactive oxygen species (ROS) released from live macrophage cells (RAW264.7) without any addition of external redox mediators using constant-height and constant-distance mode scanning electrochemical microscopy (SECM) was presented in this Letter. The successful separation of the ROS profile from the topography of cells in the physiological condition was demonstrated by recording the amperometric current and probing position in the z-direction along with lateral coordinates at each pixel where an alternating current (AC) was kept constant. It was discovered that the nucleus region of the cell releases more ROS than other organelle regions and the height of the cell is approximately 4.8 μm. To our best knowledge, this work reports the first spatially monitored ROS release without the influence of cell morphology using SECM.
Probing ds-DNA films in the presence of Zn(2+) ions by scanning electrochemical microscopy (SECM) allows the unequivocal detection of a single-nucleotide mismatch and provides information about its position within the duplex.
A recognition layer formed by multiwalled carbon nanotubes (MWCNTs) covalently modified with a ferrocene-lysine conjugate deposited on the indium tin oxide (ITO) was investigated as a sensor for chemical warfare agent (CWA) mimics. Electrochemical impedance spectroscopy measurements showed that upon addition of CWA mimic dramatic changes occurred in the electrical properties of the recognition layer. These changes allowed the detection of nerve agent analogues at the micromolar level, and a limited sensitivity was observed toward a sulfur mustard mimic. Experimental parameters were optimized so as to allow the detection of CWAs at single frequency, thereby significantly reducing acquisition time and simplifying data treatment. A proposed method of detection represents a significant step toward the design of an affordable and "fieldable" electrochemical CWA sensor.
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