Limbut Warakorn, Loyprasert Suchera, Thammakhet Chongdee, Thavarungkul Panote, Tuantranont Adisorn, Asawatreratanakul Punnee, Limsakul Chusak, Wongkittisuksa Booncharoen, Kanatharana Proespichaya
Biophysics Research Unit of Biosensors and Biocurrents, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand.
Biosens Bioelectron. 2007 Jun 15;22(12):3064-71. doi: 10.1016/j.bios.2007.01.001. Epub 2007 Jan 16.
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.
一种微流控电导生物反应器已被开发出来。通过共价结合法将酶固定在聚二甲基硅氧烷（PDMS）表面的微流控通道中。检测单元由两个金电极和一个实验室自制的电导传感器组成，用于监测由于酶-底物催化反应产生的电荷变化而导致的溶液电导率增加。尿素-脲酶被用作代表性的分析物-酶系统。在最佳条件下，尿素的检测限为0.09 mM，线性范围为0.1-10 mM（r=0.9944）。微通道芯片上固定化的脲酶具有良好的稳定性（操作时间>30天）和良好的重复性，相对标准偏差低于2.3%。当将微流控流动注射电导生物反应器系统测定的人血清样品中的尿素浓度与使用贝托洛反应获得的浓度进行比较时，得到了良好的一致性（P<0.05）。长时间使用后，固定化酶可以从PDMS微通道芯片上去除，从而能够固定新的活性酶并使芯片得以重复使用。
