title: A novel magnetic bead bioassay platform using a microchip-based sensor for infectious disease diagnosis.
abstract: New technologies are greatly needed to improve laboratory tests that can be used in point-of-care clinical settings. Here, a biosensor was used to detect micron-scale paramagnetic beads in order to replace the conventional enzymatic label used in ELISAs. This novel biosensor was fabricated through standard complementary metal oxide semiconductor (CMOS) manufacturing and was used to quantify magnetic beads bound to the sensor surface by immunological recognition, analogous to ELISA. CMOS technology can integrate multiple laboratory functions into the sensor chip, potentially enabling inexpensive, compact and sophisticated diagnostic systems for a number of diseases. We present results for two immunological assays: antigen capture of purified mouse IgG and detection of human anti-dengue virus IgG in clinical serum samples. The sensitivity of detecting purified protein with magnetic beads was comparable to ELISA. We found a high correlation between the ELISA optical density and the biosensor output in the clinical assay. We also demonstrate the use of a controlled magnetic field to remove non-specifically bound magnetic beads from the sensor surface, effectively washing the sensor surface. This novel sensor can be mass-produced at low cost and can detect magnetic beads bound to the surface through specific antibody-antigen interactions, making it a potential platform for new simplified and rapid point-of-care diagnostic tests.
authors.affiliation: Department of Electrical Engineering and Computer Sciences, University of California at Berkeley, CA 94720-3200, USA.
authors.forename: Turgut
authors.initials: T
authors.lastname: Aytur
authors.forename: Jonathan
authors.initials: J
authors.lastname: Foley
authors.forename: Mekhail
authors.initials: M
authors.lastname: Anwar
authors.forename: Bernhard
authors.initials: B
authors.lastname: Boser
authors.forename: Eva
authors.initials: E
authors.lastname: Harris
authors.forename: P Robert
authors.initials: PR
authors.lastname: Beatty
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D001681:Biological Assay / Q000295:instrumentation / Q000379:methods; D015374:Biosensing Techniques; D003141:Communicable Diseases / Q000175:diagnosis*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D017979:Gold Colloid; D006801:Humans; D008280:Magnetics; D051379:Mice; D040081:Protein Array Analysis / Q000295:instrumentation / Q000379:methods*; D012680:Sensitivity and Specificity; D020349:Surface Plasmon Resonance
chemical_list: D017979:Gold Colloid