Microfluidic conductimetric bioreactor

• Published in: Biosensors & bioelectronics 2007-06, Vol.22 (12), p.3064-3071
• Main Authors: Limbut, Warakorn, Loyprasert, Suchera, Thammakhet, Chongdee, Thavarungkul, Panote, Tuantranont, Adisorn, Asawatreratanakul, Punnee, Limsakul, Chusak, Wongkittisuksa, Booncharoen, Kanatharana, Proespichaya
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Bioreactor; Bioreactors; Biotechnology; Conductimetric; Enzymes, Immobilized - chemistry; Fundamental and applied biological sciences. Psychology; Humans; Immobilization; Microfluidic; Microfluidic Analytical Techniques - instrumentation; Microfluidic Analytical Techniques - methods; Urea; Urea - blood; Urease; Urease - chemistry
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2007.01.001

A microfluidic conductimetric bioreactor has been developed. Enzyme was immobilized in the microfluidic channel on poly-dimethylsiloxane (PDMS) surface via covalent binding method. The detection unit consisted of two gold electrodes and a laboratory-built conductimetric transducer to monitor the increase in the conductivity of the solution due to the change of the charges generated by the enzyme-substrate catalytic reaction. Urea–urease was used as a representative analyte-enzyme system. Under optimum conditions urea could be determined with a detection limit of 0.09mM and linearity in the range of 0.1–10mM (r=0.9944). The immobilized urease on the microchannel chip provided good stability (>30 days of operation time) and good repeatability with an R.S.D. lower than 2.3%. Good agreement was obtained when urea concentrations of human serum samples determined by the microfluidic flow injection conductimetric bioreactor system were compared to those obtained using the Berthelot reaction (P