title: Real-time label-free affinity biosensors for enumeration of total bacteria based on immobilized concanavalin A.
abstract: This work presents the results of the use of flow injection surface plasmon resonance and impedimetric affinity biosensors for detecting and enumerating total bacteria based on the binding between E. coli and Con A, immobilized on a modified gold electrode. The single analysis time for both techniques was less than 20 min. Dissociation between the immobilized Con A and the E. coli using 200 mM of glucose in HCl at pH of 2.00 enabling the sensor to be reused for between 29-35 times. Impedimetric detection provided a much lower limit of detection (12 CFU mL(-1)) than the surface plasmon resonance method (6.1 × 10(7) CFU mL(-1)). Using the impedimetric system, real sample analysis was performed and the results were compared to the plate count agar method. Cell concentrations obtained by the biosensor were only slightly different from the result obtained from the plate count agar. The proposed system offers a rapid and useful tool for screening detection and enumeration of total bacteria.
authors.affiliation: Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
authors.forename: Jongjit
authors.initials: J
authors.lastname: Jantra
authors.forename: Proespichaya
authors.initials: P
authors.lastname: Kanatharana
authors.forename: Punnee
authors.initials: P
authors.lastname: Asawatreratanakul
authors.forename: Martin
authors.initials: M
authors.lastname: Hedström
authors.forename: Bo
authors.initials: B
authors.lastname: Mattiasson
authors.forename: Panote
authors.initials: P
authors.lastname: Thavarungkul
mesh_terms: D058491:Bacterial Load / Q000379:methods*; D015374:Biosensing Techniques; D003208:Concanavalin A / Q000378:metabolism*; D017097:Electric Impedance; D004566:Electrodes; D004926:Escherichia coli / Q000378:metabolism*; D006046:Gold; D055767:Immobilized Proteins / Q000378:metabolism; D020349:Surface Plasmon Resonance
chemical_list: D055767:Immobilized Proteins; D003208:Concanavalin A; D006046:Gold