“…Many examples of the former type have been reported since the 1990s. Microfluidic systems with integrated microbio/chemical sensors have been fabricated for ion sensing [108,109], the determination of an enzyme substrate [24,25,46,[110][111][112][113][114][115][116][117][118][119], the analysis of enzyme [120,121], and immunoassay [122]. Various detection principles have been used based on amperometry [24,25,46,110,111,[113][114][115][116][117][118][119][120][121], potentiometry [109], and conductometry [46].…”