Analytical Sciences


Abstract − Analytical Sciences, 19(8), 1183 (2003).

Cationic Liposomes Enhanced FireflyBioluminescent Assay of Bacterial ATP in the Presence of an ATPExtractant
Naohiro NAKATA, Akihiko ISHIDA, HirofumiTANI, and Tamio KAMIDATE 
Graduate School of Engineering, HokkaidoUniversity, Kita-13, Nishi-8, Kita-ku, Sapporo 060-8628,Japan
Cationic liposomes composed of twocomponents, diethylaminoethyl-carbamoyl cholesterol andphosphatidylcholine, were applied to an enhancer for a fireflybioluminescent (BL) assay of bacterial ATP in the presence of an ATPextractant. Trichloroacetic acid (TCA), which inhibits the activity ofluciferase, was used as an ATP extractant. Cationic liposomes enhanced theBL intensity as long as luciferase was active. The detection limits forcell numbers of Escherichia coli extracts in the presence ofcationic liposomes and in water alone were 199 and 897 colony forming unitsml-1, respectively. The sensitivity for bacterial ATP in thepresence of cationic liposomes was improved by a factor of 2.5 timescompared to that in the presence of diethylaminoethyl-dextran.