This paper describes a rapid and highly sensitive chemiluminescence detection scheme for E. coli O157:H7 bacteria by using a microfluidic filter chip. The stepped configuration design of the filter chip enables the formation of a monolayer of beads-bacteria-peroxidase labeled antibodies sandwich complex inside the microchamber. The addition of Luminol to the sandwich complex produces a chemiluminescence signal proportional to the concentration of E. coli. The chemiluminescence signal is captured by a fiber optic light guide connected to a luminometer. The monolayer maximizes the optical accessibility of the E. coli cells to the detecting light guide and high chemiluminescence signal strength is achieved. A multi-sampling technique is used to enhance the E. coli capture efficiency by 180%. Due to the combination of the filter chip and the sampling technique, no enrichment scheme is used for detecting extremely low cell concentrations, which is difficult to accomplish with other rapid detection methods.

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