Wilanee Chunglok, Dyah Kinasih Wuragil, Sukunya Oaew, Mithran Somasundrum, Werasak Surareungchai
Among the methods used to detect pathogenic bacteria, enzyme linked immunosorbent assay (ELISA) is one of the most widely used techniques in routine sample analysis. For Salmonella enterica serovar Typhimurium detection, a typical ELISA yields a sensitivity of 106-107CFU/ml. To enhance the detection sensitivity, single-walled carbon nanotubes (SWCNTs) was employed in this study as a labelling platform for antibody and horseradish peroxidase (HRP) co-immobilizing. With high proteins recovery after the coupling process, the resulting Ab/SWCNTs/HRP bioconjugate was used in the proof-of-concept ELISA experiments. Limit of detection (LOD) was found to be 103 and 104CFU/ml for direct and sandwich ELISA, respectively, when Ab/HRP at 1:400 ratio was used. This figure accounts for 1000-time greater in detection sensitivity when compared to a commercial Ab-HRP conjugate. The Ab/SWCNTs/HRP bioconjugate was tested further in real samples and found a superior activity over the commercial Ab-HRP by showing 100-time greater detection limit. © 2011 Elsevier B.V.
School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bang Khun Thian, Bangkok 10150, Bang Khun Thian Chai Thale Road, Thailand; Faculty of Agricultural Technology, Brawijaya University, Malang 65145, East Java, Jl. Veteran, Indonesia; Biochemical Engineering and Pilot Plant Research and Development Unit, National Center for Genetic Engineering and Biotechnology, National Sciences and Technology Development Agency at King Mongkut's Univ. of Technology, Bangkok 10150, Thonburi (Bangkhuntien), Thailand; Biological Engineering Program, King Mongkut's University of Technology Thonburi, Bangkok 10140, Thung Khru, Pracha Uthit Road, Thailand
