层层自组装技术制备PDDA-多壁碳纳米管-胆碱生物传感器

Amperometric Choline Biosensor Based on Dispersion of Multi-walled Carbon Nanotubes in Poly( diallyldimethylammonium chloride) via Layer-by-Layer Assembly Technique

以PDDA分散多壁碳纳米管(MWCNTs),制得PDDA-MWCNTs悬浮液,采用层层自组装技术将PDDA-MWCNTs与胆碱氧化酶(ChOx)交替组装在铂(Pt)电极上,最后滴加Nafion制备抗干扰膜,构建了电流型胆碱生物传感器。实验结果表明,构建的复合酶膜(PDDA-MWCNTs/ChOx)n对底物胆碱的催化电流随着组装层数增多而明显增大,酶膜组装6层时最优。此传感器在5×10-6～2.5×10-4mol/L浓度范围内对胆碱有良好线性范围,响应时间为6.6s;灵敏度为21.97μA/mmol;检出限为2×10-6mol/L(S/N=3),RSD<5%,且传感器抗干扰能力强、稳定性好。

Poly（ diallyldimethylammonium chloride） （ PDDA） was chosen to disperse multi-walled carbon nanotubes（ MWCNTs） to prepare the stable PDDA-MWCNTs aqueous dispersion. Then,the positively charged PDDA-MWCNTs composite and negatively charged choline oxidase（ ChOx） were employed to fabricate multi-layer films on platinum（ Pt） electrodes by layer-by-layer self-assembly technique,the anti-interferential film of Nafion was dropped at the end of the last multilayer films. The results showed that MWCNTs were evenly dispersed within the PDDA films and the multilayer films of （ PDDA-MWCNTs） n could improve the catalytic current response to choline significantly with the increased number of the multilayer films. The optimum assembly number was 6. The choline biosensor fabricated showed good linear correlation from 5 × 10-6-2. 5 × 10-4 mol/L with a detection limit of 2 × 10-6mol/L（ S/N = 3） ,and the sensitivity was 21. 97 mA/mol with a response time of 6. 6 s,the RSD was less than 5% （ n = 3） . Moreover,the biosensor exhibited an excellent anti-interferential property and a good stability.