title: A fluorogenic heterogeneous immunoassay for cardiac muscle troponin cTnI on a digital microfluidic device.
abstract: We describe a fluorogenic two-site noncompetitive heterogeneous immunoassay with magnetic beads on a low-voltage digital microfluidic platform using closed electrowetting-on-dielectric (EWOD). All the steps of an enzyme-linked immunosorbent assay (ELISA) were performed on the device using 9H-(1, 3-dichloro-9, 9-dimethylacridin-2-one-7-yl) phosphate as the fluorogenic substrate for the enzyme alkaline phosphatase. The performance of the system was demonstrated with cardiac marker Troponin I (cTnI) as a model analyte in phosphate-buffered saline samples. cTnI was detected within the diagnostically relevant range with a limit of detection of 2.0 ng/mL (CV = 6.47 %). Washing of magnetic beads was achieved by movement through a narrow region of buffer bridging one drop to another with minimal fluid transfer. More than 90 % of the unbound reagents were removed after five washes. Further experiments testing human blood serum on the same platform demonstrated a sample-to-answer time at ∼18.5 min detecting 6.79 ng/mL cTnI.
authors: Electronics and Computer Science and Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK, m.tsaloglou@soton.ac.uk.
authors: Maria-Nefeli
authors: MN
authors: Tsaloglou
authors: Adrian
authors: A
authors: Jacobs
authors: Hywel
authors: H
authors: Morgan
mesh_terms: D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D044085:Microfluidics / Q000295:instrumentation / Q000379:methods*; D009206:Myocardium / Q000737:chemistry* / Q000378:metabolism; D019210:Troponin I / Q000032:analysis* / Q000378:metabolism
chemical_list: D019210:Troponin I