Tkac Jan, Whittaker James W, Ruzgas Tautgirdas
Department of Analytical Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
Biosens Bioelectron. 2007 Mar 15;22(8):1820-4. doi: 10.1016/j.bios.2006.08.014. Epub 2006 Sep 12.
Chitosan was chosen as a natural polymer for dispersion of single walled carbon nanotubes (SWNT) based on its ability to efficiently solubilize SWNTs to form a stable dispersion. Moreover, chitosan films deposited on a surface of a glassy carbon (GC) electrode are mechanically stable. Further stabilisation of the chitosan film containing SWNT (CHIT-SWNT) was done by chemical crosslinking with glutaraldehyde and free aldehyde groups produced a substrate used for covalent immobilisation of galactose oxidase (GalOD). Different galactose biosensor configurations were tested with optimisation of composition of inner and outer membrane; and enzyme immobilisation procedure, as well. Detection of oxygen uptake by GalOD on CHIT-SWNT layer at -400 mV is robust and, when flow injection analysis (FIA) was applied for assays, a low detection limit (25 microM) and very high assay throughput rate (150 h-1) was achieved. This new galactose biosensor offers highly reliable detection of galactose with R.S.D. well below 2% and it has been successfully applied to assaying galactose in a blood sample with recovery index between 101.2 and 102.7%.
基于壳聚糖能够有效溶解单壁碳纳米管（SWNT）以形成稳定分散体的能力，它被选作一种用于分散单壁碳纳米管的天然聚合物。此外，沉积在玻碳（GC）电极表面的壳聚糖膜具有机械稳定性。通过与戊二醛进行化学交联对含单壁碳纳米管的壳聚糖膜（CHIT-SWNT）进一步稳定化处理，产生的游离醛基形成了用于半乳糖氧化酶（GalOD）共价固定的底物。对不同的半乳糖生物传感器配置进行了测试，并对内、外膜的组成以及酶固定化程序进行了优化。在 -400 mV 下，通过半乳糖氧化酶对 CHIT-SWNT 层上氧气摄取的检测是可靠的，并且当应用流动注射分析（FIA）进行检测时，实现了低检测限（25 μM）和非常高的检测通量率（150 h-1）。这种新型半乳糖生物传感器对半乳糖的检测高度可靠，相对标准偏差（R.S.D.）远低于 2%，并且已成功应用于血液样本中半乳糖的检测，回收率在 101.2% 至 102.7% 之间。
