A fibre-optic biosensor for detection of microbial contamination

摘要

A firbre-optic biosensor is desensor is described for detercion of genomic targe sequences from Escherichia coli A small portion of the LazZ DNA sequence is the basis for selection of DNA probe molecules that are produced by automated mucleic acid synthessi on the surface of ptical fibres Fluorescent intercalation agents are used to report the presence of hybridization events with target strands This work veviess the fundamental design criteria for development of uncleic acid biosensore and reports a preliminary exploratin of the use of the biosensor for detecton of sequeces that mark the presence of E coli The research work includes consideration of the length of the strands and non-selective binding interaction that can potentially block the selective chemistry of create background signals The biosensors were able to detect genomic tragest from E coli at a picomole level on a time of a few minutes and dozens of cycles of use have been demonstated In a step towards the preparation of a completely self-contined sensor technology a new intercalating dye known as SYBR 101 (Molecular Prodbes Inc) has been end-labelled to the LacZ nucleic acid probe to esamine whether dye techered onto an olignucleotide terminus could fluorimetrically transduce the formation of hybrids The results obtined from experiments on solution indicate that the use of tethered dye provides fluorescence signals that are due to hybgridizatinand that this process is functional even in hte presence of a high concentration of non-selcective background DNA obtained from sonicated salmon sperm.