title: Anionic conjugated polymer with aptamer-functionalized silica nanoparticle for label-free naked-eye detection of lysozyme in protein mixtures.
abstract: An assay triggered by recognition-induced charge switching is developed for protein detection and quantification. Aptamer-functionalized silica nanoparticles (NPs) have been synthesized to capture lysozyme, resulting in an alternation of the surface charge from negative to partially positive. The binding event is then translated and monitored by the fluorescence signal of a highly fluorescent anionic poly(fluorene-alt-vinylene) (PFVSO(3)), which "stains" on protein/aptamer-NP complexes via electrostatic interaction. Blue-greenish fluorescence of PFVSO(3) is observed in the presence of lysozyme by the naked eye, while no fluorescence is obtained for NPs upon treatment with a mixture of foreign proteins. A linear relationship between NP fluorescence and lysozyme is observed in the concentration range of 0-22.5 microg/mL, which gives a limit of detection as approximately 0.36 microg/mL. This work demonstrates a convenient label-free conjugated polyelectrolyte (CPE)-based protein detection with high specificity and sensitivity, which has potential applications in medical diagnosis.
authors.affiliation: Department of Chemical and Biomolecular Engineering, 4 Engineering Drive 4, National University of Singapore, 117576 Singapore.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Wang
authors.forename: Kan-Yi
authors.initials: KY
authors.lastname: Pu
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
mesh_terms: D052158:Aptamers, Peptide; D009113:Muramidase / Q000032:analysis*; D053758:Nanoparticles / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011506:Proteins; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide
chemical_list: D052158:Aptamers, Peptide; D011108:Polymers; D011506:Proteins; D012822:Silicon Dioxide; D009113:Muramidase