title: Label-free biomolecular detection at electrically displaced liquid interfaces using interfacial electrokinetic transduction (IET).
abstract: Biosensors require a biorecognition element that specifically binds to a target analyte, and a signal transducer, which converts this targeted binding event into a measurable signal. While current biosensing methods are capable of sensitively detecting a variety of target analytes in a laboratory setting, there are inherent difficulties in developing low-cost portable biosensors for point-of-care diagnostics using traditional optical, mass, or electroanalytical-based signal transducers. It is therefore important to develop new biosensing transducer elements for recognizing binding events at low cost and in portable environments. Here, we demonstrate a novel electrokinetic liquid biosensing method for the sensitive label-free detection of a model biomolecule against a background of serum protein. The biosensor is based on the motion of a microfluidic-generated electrical liquid interface when subjected to an external alternating current electrical field. We demonstrate that the electric field-induced motion of the interface can be used as a sensitive and specific transducer for the detection of avidin at femtomolar concentrations in solution. This new detection strategy does not require surface functionalization or fluorescent labels, and has the potential to serve as a sensitive low-cost method for portable biomarker detection.
authors.affiliation: Johns Hopkins University, 3400 North Charles Street, Maryland Hall 221C, Baltimore, MD 21218, United States of America.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Mavrogiannis
authors.affiliation: Johns Hopkins University, 3400 North Charles Street, Maryland Hall 221C, Baltimore, MD 21218, United States of America.
authors.forename: Francesca
authors.initials: F
authors.lastname: Crivellari
authors.affiliation: Johns Hopkins University, 3400 North Charles Street, Maryland Hall 220A, Baltimore, MD 21218, United States of America.
authors.forename: Zachary R
authors.initials: ZR
authors.lastname: Gagnon
mesh_terms: D001360:Avidin / Q000097:blood*; D001797:Blood Protein Electrophoresis / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation*; D056656:Lab-On-A-Chip Devices; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013194:Staining and Labeling
chemical_list: D001360:Avidin
keywords: Biosensing; Dielectrophoresis; Electrokinetics; Interfacial polarization; Microfluidics