Continuous monitoring of ascorbate transport through neuroblastoma cells with a ruthenium oxide hexacyanoferrate modified microelectrode

Author(s)

Paixaeo, Thiago R. L. C. ^[1] ; Barbosa, Livea F. ^[1] ; Carri, Maria T. ^{[2, 3]} ; Medeiros, Marisa H. G. ^[1] ; Bertotti, Mauro ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Quim, BR-05508900 Sao Paulo - Brazil

^[2] Univ Roma Tor Vergata, Dept Biol, I-00133 Rome - Italy

^[3] Fdn Santa Lucia IRRCS, Rome - Italy

• Document type: Journal article
• Source: ANALYST; v. 133, n. 11, p. 1605-1610, 2008.
• Web of Science Citations: 11

Abstract

The uptake of ascorbate by neuroblastoma cells using a ruthenium oxide hexacyanoferrate (RuOHCF)-modified carbon fiber disc (CFD) microelectrode (r = 14.5 mu m) was investigated. By use of the proposed electrochemical sensor the amperometric determination of ascorbate was performed at 0.0 V in minimum essential medium (MEM, pH = 7.2) with a limit of detection of 25 mu mol L(-1). Under the optimum experimental conditions, no interference from MEM constituents and reduced glutathione (used to prevent the oxidation of ascorbate during the experiments) was noticed. The stability of the RuOHCF-modified electrode response was studied by measuring the sensitivity over an extended period of time (120 h), a decrease of around 10% being noticed at the end of the experiment. The rate of ascorbate uptake by control human neuroblastoma SH-SY5Y cells, and cells transfected with wild-type Cu,Zn-superoxide dismutase (SOD WT) or with a mutant typical of familial amyotrophic lateral sclerosis (SOD G93A), was in agreement with the level of oxidative stress in these cells. The usefulness of the RuOHCF-modified microelectrode for in vivo monitoring of ascorbate inside neuroblastoma cells was also demonstrated. (AU)