A screen-printed microband glucose bioensor system for real-time monitoring of toxicity in cell culture
Pemberton, R., Xu, J., Pittson, R., Drago, G. A., Griffiths, J., Jackson, S. K. and Hart, J. P. (2011) A screen-printed microband glucose bioensor system for real-time monitoring of toxicity in cell culture. Biosensors and Bioelectronics, 26 (5). pp. 2448-2453. ISSN 0956-5663 Available from: http://eprints.uwe.ac.uk/13709
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Publisher's URL: http://dx.doi.org/10.1016/j.bios.2010.10.030
Microband biosensors, screen-printed from a water-based carbon ink containing cobalt phthalocyanine redox mediator and glucose oxidase (GOD) enzyme, were used to monitor glucose levels continuously in buffer and culture medium. Five biosensors were operated amperometrically (Eapp of +0.4 V), in a 12-well tissue culture plate system at 37 oC, using a multipotentiostat. After 24h, a linear calibration plot was obtained from steady-state current responses for glucose concentrations up to 10 mM (dynamic range 30 mM). Within the linear region, a correlation coefficient (R2) of 0.981 was obtained between biosensor and spectrophotometric assays. Over 24 h, an estimated 0.15% (89 nanomoles) of the starting glucose concentration (24 mM) was consumed by the microbiosensor. The sensitivity of the biosensor response in full culture medium was stable between pHs 7.3 and 8.4. Amperometric responses for HepG2 monolayer cultures decreased with time in inverse proportionality to cell number (for 0 to 1 million cell/ml), as glucose was being metabolised. HepG2 3D cultures (spheroids) were also shown to metabolise glucose, at a rate which was independent of spheroid age (between 6 and 15 days). Spheroids were used to assay the effect of a typical hepatotoxin, paracetamol. At 1 mM paracetamol, glucose uptake was inhibited by 95% after 6 h in culture; at 500 microM, around 15% inhibition was observed after 16 h. This microband biosensor culture system could form the basis for an in-vitro toxicity testing system.