REASSESSMENT OF A GANGLIOSIDE-LIPOSOME BIOSENSOR

Botulism, the disease caused by the introduction of botulinum toxin (BT) into the body, is a rare but severe ailment that frequently results in death from respiratory failure. Cholera, the disease caused by the introduction of cholera toxin (CT) into the body, is a much more common problem in third world countries, causing severe diarrhea and dehydration. In this study, the design of previously developed sensitive biosensors for the detection of BT and CT has been scrutinized, with the intention of improving upon the detection limit the BT assay. This biosensor is a test strip assay which utilizes ganglioside-incorporated liposomes, and toxin antibodies which are immobilized on an analytical zone of a plastic-backed nitrocellulose membrane strip to form a sandwich-type detection mechanism. The intensity of the band could be visually estimated or measured by densitometry, using computer software. Previous studies with this design obtained a limit of detection (LoD) of 15 pg/mL and 10 fg/mL in 20 minutes for BT and CT, respectively. Difficulties in obtaining any concentration gradient in the detection of BT, converted this study into a reassessment of this prior design. All attempts to obtain a BT biosensor similar to that developed in the previous study failed to obtain a LoD greater than 10 ?g/mL, and took at least 35 minutes to complete. A similar attempt to recreate the CT biosensor design yielded a LoD no greater than 0.64 ng/mL, but took only 15-20 minutes to complete. The results from this study suggest that the design of the bioassay developed for BT should be reconsidered, and that further studies should be undertaken to consider alternative approaches to this assay