title: Microelectrode Arrays of Diamond-Insulated Graphitic Channels for Real-Time Detection of Exocytotic Events from Cultured Chromaffin Cells and Slices of Adrenal Glands.
abstract: A microstructured graphitic 4 × 4 multielectrode array was embedded in a single-crystal diamond substrate (4 × 4 μG-SCD MEA) for real-time monitoring of exocytotic events from cultured chromaffin cells and adrenal slices. The current approach relies on the development of a parallel ion beam lithographic technique, which assures the time-effective fabrication of extended arrays with reproducible electrode dimensions. The reported device is suitable for performing amperometric and voltammetric recordings with high sensitivity and temporal resolution, by simultaneously acquiring data from 16 rectangularly shaped microelectrodes (20 × 3.5 μm(2)) separated by 200 μm gaps. Taking advantage of the array geometry we addressed the following specific issues: (i) detect both the spontaneous and KCl-evoked secretion simultaneously from several chromaffin cells directly cultured on the device surface, (ii) resolve the waveform of different subsets of exocytotic events, and (iii) monitoring quantal secretory events from thin slices of the adrenal gland. The frequency of spontaneous release was low (0.12 and 0.3 Hz, respectively, for adrenal slices and cultured cells) and increased up to 0.9 Hz after stimulation with 30 mM KCl in cultured cells. The spike amplitude as well as rise and decay time were comparable with those measured by carbon fiber microelectrodes and allowed to identify three different subsets of secretory events associated with "full fusion" events, "kiss-and-run" and "kiss-and-stay" exocytosis, confirming that the device has adequate sensitivity and time resolution for real-time recordings. The device offers the significant advantage of shortening the time to collect data by allowing simultaneous recordings from cell populations either in primary cell cultures or in intact tissues.
authors.affiliation: Istituto Nazionale di Fisica Nucleare (INFN) , 10125 Torino, Italy.|Physics Department, University of Torino , 10125 Torino, Italy.|"Nanostructured Interfaces and Surfaces" Inter-departmental Centre, University of Torino , 10125 Torino, Italy.|Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM) , Torino Unit, 10125 Torino, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Picollo
authors.affiliation: Istituto Nazionale di Fisica Nucleare (INFN) , 10125 Torino, Italy.|Physics Department, University of Torino , 10125 Torino, Italy.|"Nanostructured Interfaces and Surfaces" Inter-departmental Centre, University of Torino , 10125 Torino, Italy.|Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM) , Torino Unit, 10125 Torino, Italy.
authors.forename: Alfio
authors.initials: A
authors.lastname: Battiato
authors.affiliation: Istituto Nazionale di Fisica Nucleare (INFN) , 10125 Torino, Italy.|Physics Department, University of Torino , 10125 Torino, Italy.|"Nanostructured Interfaces and Surfaces" Inter-departmental Centre, University of Torino , 10125 Torino, Italy.|Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM) , Torino Unit, 10125 Torino, Italy.
authors.forename: Ettore
authors.initials: E
authors.lastname: Bernardi
authors.affiliation: "Nanostructured Interfaces and Surfaces" Inter-departmental Centre, University of Torino , 10125 Torino, Italy.|Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM) , Torino Unit, 10125 Torino, Italy.|Department of Drug Science and Technology, University of Torino , 10125 Torino, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Marcantoni
authors.affiliation: Institute of Electron Devices and Circuits, Ulm University , 89081 Ulm, Germany.
authors.forename: Alberto
authors.initials: A
authors.lastname: Pasquarelli
authors.affiliation: "Nanostructured Interfaces and Surfaces" Inter-departmental Centre, University of Torino , 10125 Torino, Italy.|Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM) , Torino Unit, 10125 Torino, Italy.|Department of Drug Science and Technology, University of Torino , 10125 Torino, Italy.
authors.forename: Emilio
authors.initials: E
authors.lastname: Carbone
authors.affiliation: Istituto Nazionale di Fisica Nucleare (INFN) , 10125 Torino, Italy.|Physics Department, University of Torino , 10125 Torino, Italy.|"Nanostructured Interfaces and Surfaces" Inter-departmental Centre, University of Torino , 10125 Torino, Italy.|Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM) , Torino Unit, 10125 Torino, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Olivero
authors.affiliation: "Nanostructured Interfaces and Surfaces" Inter-departmental Centre, University of Torino , 10125 Torino, Italy.|Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM) , Torino Unit, 10125 Torino, Italy.|Department of Drug Science and Technology, University of Torino , 10125 Torino, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Carabelli
mesh_terms: D000311:Adrenal Glands / Q000378:metabolism*; D000818:Animals; D015374:Biosensing Techniques / Q000379:methods; D002395:Catecholamines / Q000032:analysis; D002417:Cattle; D002478:Cells, Cultured; D019439:Chromaffin Cells / Q000378:metabolism*; D018130:Diamond / Q000737:chemistry*; D005089:Exocytosis; D006108:Graphite / Q000737:chemistry*; D056656:Lab-On-A-Chip Devices; D051379:Mice; D008839:Microelectrodes
chemical_list: D002395:Catecholamines; D018130:Diamond; D006108:Graphite