title: Microfluidic conductimetric bioreactor.
abstract: 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 0.09 mM and linearity in the range of 0.1-10 mM (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<0.05). After prolong use the immobilized enzyme could be removed from the PDMS microchannel chip enabling new active enzyme to be immobilized and the chip to be reused.
authors.affiliation: Biophysics Research Unit of Biosensors and Biocurrents, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand.
authors.forename: Warakorn
authors.initials: W
authors.lastname: Limbut
authors.forename: Suchera
authors.initials: S
authors.lastname: Loyprasert
authors.forename: Chongdee
authors.initials: C
authors.lastname: Thammakhet
authors.forename: Panote
authors.initials: P
authors.lastname: Thavarungkul
authors.forename: Adisorn
authors.initials: A
authors.lastname: Tuantranont
authors.forename: Punnee
authors.initials: P
authors.lastname: Asawatreratanakul
authors.forename: Chusak
authors.initials: C
authors.lastname: Limsakul
authors.forename: Booncharoen
authors.initials: B
authors.lastname: Wongkittisuksa
authors.forename: Proespichaya
authors.initials: P
authors.lastname: Kanatharana
mesh_terms: D019149:Bioreactors; D004800:Enzymes, Immobilized / Q000737:chemistry*; D006801:Humans; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods; D014508:Urea / Q000097:blood*; D014510:Urease / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; D014508:Urea; D014510:Urease