title: Development of an array of ion-selective microelectrodes aimed for the monitoring of extracellular ionic activities.
abstract: In this study, we present the development and the characterization of a generic platform for cell culture able to monitor extracellular ionic activities (K+, NH4+) for real-time monitoring of cell-based responses, such as necrosis, apoptosis, or differentiation. The platform for cell culture is equipped with an array of 16 silicon nitride micropipet-based ion-selective microelectrodes with a diameter of either 2 or 6 microm. This array is located at the bottom of a 200-microm-wide and 350-microm-deep microwell where the cells are cultured. The characterization of the ion-selective microelectrode arrays in different standard and physiological solutions is presented. Near-Nernstian slopes were obtained for potassium- (58.6 +/- 0.8 mV/pK, n = 15) and ammonium-selective microelectrodes (59.4 +/- 3.9 mV/pNH4, n = 13). The calibration curves were highly reproducible and showed an average drift of 4.4 +/- 2.3 mV/h (n = 10). Long-term behavior and response after immersion in physiological solutions are also presented. The lifetime of the sensors was found to be extremely long with a high recovery rate.
authors.affiliation: Center for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA. olivier.guenat@ unine.ch
authors.forename: Olivier T
authors.initials: OT
authors.lastname: Guenat
authors.forename: Silvia
authors.initials: S
authors.lastname: Generelli
authors.forename: Nicolaas F
authors.initials: NF
authors.lastname: de Rooij
authors.forename: Milena
authors.initials: M
authors.lastname: Koudelka-Hep
authors.forename: François
authors.initials: F
authors.lastname: Berthiaume
authors.forename: Martin L
authors.initials: ML
authors.lastname: Yarmush
mesh_terms: D017736:Ion-Selective Electrodes; D008839:Microelectrodes; D008855:Microscopy, Electron, Scanning; D012680:Sensitivity and Specificity