title: Electrokinetic effect for molecular recognition: A label-free approach for real-time biosensing.
abstract: We present a simple and inexpensive method for label-free detection of biomolecules. The method monitors the changes in streaming current in a fused silica capillary as target biomolecules bind to immobilized receptors on the inner surface of the capillary. To validate the concept, we show detection and time response of different protein-ligand and protein-protein systems: biotin-avidin and biotin-streptavidin, barstar-dibarnase and Z domain-immunoglobulin G (IgG). We show that specific binding of these biomolecules can be reliably monitored using a very simple setup. Using sequential injections of various proteins at a diverse concentration range and as well as diluted human serum we further investigate the capacity of the proposed technique to perform specific target detection from a complex sample. We also investigate the time for the signal to reach equilibrium and its dependence on analyte concentration and demonstrate that the current setup can be used to detect biomolecules at a concentration as low as 100pM without requiring any advanced device fabrication procedures. Finally, an analytical model based on diffusion theory has been presented to explain the dependence of the saturation time on the analyte concentration and capillary dimensions and how reducing length and inner diameter of the capillary is predicted to give faster detection and in practice also lower limit of detection.
authors.affiliation: Department of Materials and Nano Physics, School of Information and Communication Technology, KTH Royal Institute of Technology, 16440 Kista, Sweden; Solid-State Electronics, The Ångström Laboratory, Uppsala University, Uppsala Box 534, SE-751 21, Sweden. Electronic address: apurbad@kth.se.
authors.forename: Apurba
authors.initials: A
authors.lastname: Dev
authors.affiliation: Division of Protein Technology, School of Biotechnology, KTH Royal Institute of Technology, AlbaNova University Center, 10691 Stockholm, Sweden.
authors.forename: Josef
authors.initials: J
authors.lastname: Horak
authors.affiliation: Division of Protein Technology, School of Biotechnology, KTH Royal Institute of Technology, AlbaNova University Center, 10691 Stockholm, Sweden.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kaiser
authors.affiliation: Institut de Nanotechnologies de Lyon (INL), UMR 5270 CNRS-UCBL-INSA-ECL Bât. Léon Brillouin Université Claude Bernard - Lyon 1, 69622 Villeurbanne Cedex, France.
authors.forename: Xichen
authors.initials: X
authors.lastname: Yuan
authors.affiliation: Division of Protein Technology, School of Biotechnology, KTH Royal Institute of Technology, AlbaNova University Center, 10691 Stockholm, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Perols
authors.affiliation: Swedish ICT Acreo AB, SE-164 40 Stockholm, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Björk
authors.affiliation: Division of Protein Technology, School of Biotechnology, KTH Royal Institute of Technology, AlbaNova University Center, 10691 Stockholm, Sweden.
authors.forename: Amelie Eriksson
authors.initials: AE
authors.lastname: Karlström
authors.affiliation: Institut de Nanotechnologies de Lyon (INL), UMR 5270 CNRS-UCBL-INSA-ECL Bât. Léon Brillouin Université Claude Bernard - Lyon 1, 69622 Villeurbanne Cedex, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Kleimann
authors.affiliation: Department of Materials and Nano Physics, School of Information and Communication Technology, KTH Royal Institute of Technology, 16440 Kista, Sweden.
authors.lastname: Jan Linnros
mesh_terms: D001360:Avidin / Q000032:analysis; D000069977:Bacillus amyloliquefaciens / Q000201:enzymology; D001426:Bacterial Proteins / Q000032:analysis; D015374:Biosensing Techniques / Q000295:instrumentation*; D001710:Biotin / Q000032:analysis; D004867:Equipment Design; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D008024:Ligands; D011506:Proteins / Q000032:analysis*; D012260:Ribonucleases / Q000032:analysis; D013205:Staphylococcal Protein A / Q000032:analysis; D013211:Staphylococcus aureus / Q000737:chemistry; D019809:Streptavidin / Q000032:analysis; D013302:Streptomyces / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D007074:Immunoglobulin G; D008024:Ligands; D011506:Proteins; D013205:Staphylococcal Protein A; D001360:Avidin; C057438:barstar protein, Bacillus amyloliquefaciens; D001710:Biotin; D019809:Streptavidin; D012260:Ribonucleases; C019760:Bacillus amyloliquefaciens ribonuclease
keywords: Diffusion model; Electrokinetic effect; Human serum analysis; Immunosensor; Label-free detection; Real-time biodetection