title: Nanoelectrodes for determination of reactive oxygen and nitrogen species inside murine macrophages.
abstract: Reactive oxygen and nitrogen species (ROS and RNS) produced by macrophages are essential for protecting a human body against bacteria and viruses. Micrometer-sized electrodes coated with Pt black have previously been used for selective and sensitive detection of ROS and RNS in biological systems. To determine ROS and RNS inside macrophages, one needs smaller (i.e., nanometer-sized) sensors. In this article, the methodologies have been extended to the fabrication and characterization of Pt/Pt black nanoelectrodes. Electrodes with the metal surface flush with glass insulator, most suitable for quantitative voltammetric experiments, were fabricated by electrodeposition of Pt black inside an etched nanocavity under the atomic force microscope control. Despite a nanometer-scale radius, the true surface area of Pt electrodes was sufficiently large to yield stable and reproducible responses to ROS and RNS in vitro. The prepared nanoprobes were used to penetrate cells and detect ROS and RNS inside macrophages. Weak and very short leaks of ROS/RNS from the vacuoles into the cytoplasm were detected, which a macrophage is equipped to clean within a couple of seconds, while higher intensity oxidative bursts due to the emptying of vacuoles outside persist on the time scale of tens of seconds.
authors.affiliation: Department of Chemistry and Biochemistry, Queens College-City University of New York, Flushing, NY 11367, USA.
authors.forename: Yixian
authors.initials: Y
authors.lastname: Wang
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Noël
authors.forename: Jeyavel
authors.initials: J
authors.lastname: Velmurugan
authors.forename: Wojciech
authors.initials: W
authors.lastname: Nogala
authors.forename: Michael V
authors.initials: MV
authors.lastname: Mirkin
authors.forename: Cong
authors.initials: C
authors.lastname: Lu
authors.forename: Manon
authors.initials: M
authors.lastname: Guille Collignon
authors.forename: Frédéric
authors.initials: F
authors.lastname: Lemaître
authors.forename: Christian
authors.initials: C
authors.lastname: Amatore
mesh_terms: D000818:Animals; D004566:Electrodes; D004595:Electroplating / Q000379:methods; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D018625:Microscopy, Atomic Force; D015335:Molecular Probes / Q000138:chemical synthesis*; D049329:Nanostructures / Q000737:chemistry*; D010984:Platinum; D026361:Reactive Nitrogen Species / Q000737:chemistry / Q000302:isolation & purification*; D017382:Reactive Oxygen Species / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D015335:Molecular Probes; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D010984:Platinum