Fabrication of amperometric biosensor for the detection of gram-negative bacteria

• Main Authors: Chang, Heng-Yi, 張恒毅
• Other Authors: Yuan, Chiun-Jye
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/13347029865595026383

碩士 === 國立交通大學 === 分子醫學與生物工程研究所 === 98 === An amperometric biosensor was developed in this study for the rapid and sensitive detection of gram-negative bacteria This amperometric biosensor (GM(-)-bacterial biosensor) was fabricated by immobilizing a gram-negative bacteria-sensitive glycoprotein on the screen-printed carbon paste electrode (SPCE) with chitosan. Escherichia coli was used a model of gram-negative bacteria to investigate the availability of the fabricated biosensor. The attached E. coli cells on the SPCE were then detected by the ferrocene and mannose-conjugated gold nanoparticle (f/m-GNP), ferrocene and mannosyl groups. Studies show that the developed f/m-GNP is water-dispersible with a diameter of around 31 nm and contains an average of 910 ferrocenes per f/m-GNP. The capability of f/m-GNPs to bind E. coli was demonstrated by cyclic voltammetry and its ability to aggregate with ConA. The reagentless detection of E. coli was performed by chronoamperometry. The results show that the faradaic anodic current (Fe2+ to Fe3+) is linearly proportional to the E. coli concentration between 2.92×104 and 2.92×108 CFU/mL (R2 = 0.9737). The lowest detection limit of GM(-)-bacterial biosensor was approximately 2.92×104 CFU/ml. The developed GM(-)-bacterial biosensor exhibits a extreme high specificity to gram-negative bacteria.