Syu Mei-Jywan, Chang Yu-Sung
Department of Chemical Engineering, National Cheng Kung University, No. 1, Ta-Hseuh Rd., Tainan 70101, Taiwan.
Biosens Bioelectron. 2009 Apr 15;24(8):2671-7. doi: 10.1016/j.bios.2009.01.036. Epub 2009 Feb 2.
Potentio-dynamic polymerization of buffered urease and pyrrole monomer onto carbon papers was conducted to fabricate an immobilized urease electrode for measuring the urea concentration. To use carbon paper as the substrate for the electro-growth of polypyrrole matrix not only created sufficient adhesion of the conducting polymer layer but also provided superior entrapment of urease enzymes. The potentiometric response corresponding to ammonia, the product formed from the urease catalyzed urea reaction, was employed for the urea concentration measurement. Scanning electron microscopic photographs showed that the polypyrrole matrix deposited on the carbon papers appeared to be of a cylindrical nanotube shape. The charge density applied in the polymerization was found to affect the potentiometric response while the potential-scanning rate showed minor influence. The composite electrodes had high sensitivity in urea detection, showing a response linear to the logarithm of the urea concentration in the range of 10(-3) to 10 mM. The detection of urea solution prepared in water and buffer was also compared. Ionic effect on the sensing of urea solution was investigated. By comparing the data reported in literature, the urease/polypyrrole/carbon paper electrode developed in this work showed superior long-term stability and reusability. The detection of urea in serum was also well performed.
通过将缓冲脲酶和吡咯单体在碳纸上进行电位动态聚合，制备了一种用于测量尿素浓度的固定化脲酶电极。使用碳纸作为聚吡咯基质电生长的基底，不仅能使导电聚合物层有足够的附着力，还能更好地截留脲酶。由脲酶催化尿素反应生成的产物氨的电位响应被用于测量尿素浓度。扫描电子显微镜照片显示，沉积在碳纸上的聚吡咯基质呈圆柱形纳米管形状。发现聚合过程中施加的电荷密度会影响电位响应，而电位扫描速率的影响较小。复合电极在尿素检测中具有高灵敏度，在10(-3)至10 mM范围内，对尿素浓度的对数呈线性响应。还比较了在水和缓冲液中制备的尿素溶液的检测情况。研究了离子对尿素溶液传感的影响。通过与文献报道的数据比较，本工作中开发的脲酶/聚吡咯/碳纸电极显示出优异的长期稳定性和可重复使用性。血清中尿素的检测也表现良好。
