title: Development of an electrochemical Limulus amebocyte lysate assay technique for portable and highly sensitive endotoxin sensor.
abstract: Here, we report the development of an electrochemical detection method for endotoxin based on the Limulus amebocyte lysate (LAL) assay. A mixture of LAL reagent and endotoxin sample solution was incubated for 1 h. The endotoxin activated a cascade reaction of zymogens contained in the LAL to generate p-nitroaniline (pNA) which was then electrochemically detected by differential pulse voltammetry (DPV). The generated pNA gave a clear peak at -0.75 V vs. silver/silver chloride (Ag/AgCl), which increased with the concentration of endotoxin in the LAL assay solution. This DPV detection was performed using an electrode chip device fabricated from a diamond-like carbon-coated glass substrate. This chip device could detect as low as 10 endotoxin units l(-1) at room temperature within 1 h. This novel electrochemical method for the detection of endotoxin appears promising for the development of compact, low-cost and easy-to-use sensors for on-site monitoring of potentially contaminated medical supplies, including dialysis fluid, transplanted tissue and culture medium for assisted reproduction.
authors.affiliation: R&D Center of Excellence of Integrated Microsystems, Tohoku University, Aramaki, Aoba, Sendai, Japan. inoue@bioinfo.che.tohoku.ac.jp
authors.forename: Kumi Y
authors.initials: KY
authors.lastname: Inoue
authors.forename: Satoko
authors.initials: S
authors.lastname: Takahashi
authors.forename: Kosuke
authors.initials: K
authors.lastname: Ino
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Shiku
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Matsue
mesh_terms: D000465:Algorithms; D000814:Aniline Compounds / Q000737:chemistry; D000818:Animals; D060829:Arthropod Proteins / Q000378:metabolism; D015374:Biosensing Techniques; D004563:Electrochemistry; D004566:Electrodes; D004731:Endotoxins / Q000032:analysis*; D004792:Enzyme Precursors / Q000378:metabolism; D004867:Equipment Design; D007202:Indicators and Reagents; D056656:Lab-On-A-Chip Devices; D008033:Limulus Test / Q000295:instrumentation* / Q000379:methods*; D009842:Oligopeptides / Q000737:chemistry; D010100:Oxygen / Q000097:blood; D012697:Serine Endopeptidases / Q000378:metabolism; D012815:Signal Processing, Computer-Assisted; D018030:Silver Compounds / Q000737:chemistry
chemical_list: D000814:Aniline Compounds; D060829:Arthropod Proteins; D004731:Endotoxins; D004792:Enzyme Precursors; D007202:Indicators and Reagents; D009842:Oligopeptides; D018030:Silver Compounds; C019498:4-nitroaniline; C035732:butyloxycarbonyl-leucyl-glycyl-arginine-4-nitroanilide; D012697:Serine Endopeptidases; C057151:Limulus clotting factor C; C037548:silver chloride; D010100:Oxygen