A high-efficiency capillary or microfluidic bio-separator/reactor comprises the heart of this technology. The bio-separator/reactor captures target pathogens from a sample and hosts the immunological and enzymatic reaction, which is followed by an optical or electrochemical measurement. Both the optical and electrochemical modes can detect Escherichia coli O157:H7 down to 10-100 cells/ml in 1-2 hours without any sample pre-enrichment .

Typical output (left) and calibration graph (right) of optical microfluidic biosensor for detection of E. coli O157:H7.

Typical output (left) and calibration graph (right) of electrochemical microfluidic biosensor for detection of E. coli O157:H7.

Y. Liu, Y. Li. 2001. An antibody-immobilized capillary column as a bioseparator/bioreactor for detection of E. coli O157:H7 with absorbance measurement. Anal. Chem. 73 (21), 5180-5183.

Z. Zhang, C. Ruan, Y. Li. 2002. Capillary column-based bioseparator/bioreactor coupled with an electrochemical biosensor for detection of Escherichia coli O157:H7. ASAE Paper No. 027015. The American Society of Agricultural Engineers, St. Joseph , MI.

X.-L. Su, Z. Zhang, B. Kim, Y. Li. 2003. Capillary immunosensing system for rapid detection of Salmonella Typhimurium. ASAE Paper No. 037061. The American Society of Agricultural Engineers, St. Joseph , MI.

B. Kim, X.-L. Su, Y. Li. 2005. Evaluation of a capillary immunoassay system for detection of Salmonella Typhimurium in poultry products. J. Food Prot. (in press).