On-chip electrochemical measurement of β-galactosidase expression using a microbial chip

β-Galactosidase expression in a small number of Escherichia coli cells has been measured in real time with an electrochemical sensor chip. E. coli cells were embedded using collagen gel within a micropore which was microfabricated onto a chip. The activity of the expressed β-galactosidase was determined using p-aminophenyl β-d-galactopyranoside (PAPG) as a substrate.