SiM20 Posters

23 Sensors in Medicine 2020 Assay principle magnetic bead liposome magnet capture probe target DNA reporter probe • Successful integration of ECL-based liposome assay into a simple microfluidic system • On-chip assay optimization with respect to volumes used, incubation times and detection modes will lead to lower LOD than the off-chip system • Application to analysis of DNA or RNA sequences generated by nucleic acid amplification methods such as PCR, NASBA or RPA Results Conclusion & Outlook • Stepwise incubation of streptavidin coated magnetic beads with: − biotinylated capture probe − target DNA (derived from C. parvum hsp70 mRNA) − Ru(bpy) 3 2+ encapsulating liposomes tagged with reporter probes • Injection of resulting sandwich complex into microfluidic chips → separation of bound and unbound liposomes by a magnet (1) • Transfer of the washed sandwich complex onto the working electrode by magnetic force (2) • Lysis of liposomes by surfactants (2) • Detection of releseased Ru(bpy) 3 2+ via ECL at 610 nm at 1.2 V (vs Ag/AgCl) (2) • Without optimization, on-chip assay performs as well as off-chip assay • 40x lower working electrode size in microfluidic system does not negatively affect assay 0 .001 0.01 0.1 1 10 100 0 0 2 4 6 8 10 off-chip ECL intensity integral / a.u. c (target DNA) / nmol∙L -1 LOD = 45 pmol∙L -1 0 .001 0.01 0.1 1 10 100 0 0 2 4 6 8 10 on-chip ECL intensity integral / a.u. c (target DNA) / nmol∙L -1 LOD = 133 pmol∙L -1 1) 2)