title: Magnetic actuator for the control and mixing of magnetic bead-based reactions on-chip.
abstract: While magnetic bead (MB)-based bioassays have been implemented in integrated devices, their handling on-chip is normally either not optimal--i.e. only trapping is achieved, with aggregation of the beads--or requires complex actuator systems. Herein, we describe a simple and low-cost magnetic actuator to trap and move MBs within a microfluidic chamber in order to enhance the mixing of a MB-based reaction. The magnetic actuator consists of a CD-shaped plastic unit with an arrangement of embedded magnets which, when rotating, generate the mixing. The magnetic actuator has been used to enhance the amplification reaction of an enzyme-linked fluorescence immunoassay to detect Escherichia coli O157:H7 whole cells, an enterohemorrhagic strain, which have caused several outbreaks in food and water samples. A 2.7-fold sensitivity enhancement was attained with a detection limit of 603 colony-forming units (CFU) /mL, when employing the magnetic actuator.
authors.affiliation: Group of Sensors and Biosensors (GSB), Department of Chemistry, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Berenguel-Alonso
authors.forename: Xavier
authors.initials: X
authors.lastname: Granados
authors.forename: Jordi
authors.initials: J
authors.lastname: Faraudo
authors.forename: Julián
authors.initials: J
authors.lastname: Alonso-Chamarro
authors.forename: Mar
authors.initials: M
authors.lastname: Puyol
mesh_terms: D004867:Equipment Design; D004927:Escherichia coli Infections / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D006801:Humans; D018189:Immunomagnetic Separation / Q000191:economics / Q000295:instrumentation*; D057230:Limit of Detection; D060328:Magnetic Phenomena; D046210:Microfluidic Analytical Techniques / Q000191:economics / Q000295:instrumentation*