Objective   To study the efficiency of concentration and capture of enterohemorrhagic Escherichia coli (EHEC) O157∶H7 by a self-made microfluidic chip based on microbead.     Methods   The anti-EHEC O157∶H7 antibody was first attached on the microbeads by direct covalent linkage

then the microbeads were filled into microfluidic chip. Thus

the bacteria capture chip was set up. Totally 1.6×10

9

CFU fluorescence labeled bacteria flowed into the chip at a sampling speed of 1

2 and 5 μl/min respectively

and the elution speed of 0.5

2

5

10 and 20 μl/min. The specific capture efficiency of the chip was strengthened through the optimization of sampling speed

elution speed and time.    Results   The best sampling speed

elution speed and time were 5

μl/min

10 μl/min and 5 min respectively. There was significant difference between the test group and the control group (P0.01).    Conclusion   Our self-made bacteria capture chip is of high catching efficiency

which lay a good base for the construction of rapid detection microfluidic system of bacteria.