title: Digital microfluidic platform for the detection of rubella infection and immunity: a proof of concept.
abstract: BACKGROUND
  Whereas disease surveillance for infectious diseases such as rubella is important, it is critical to identify pregnant women at risk of passing rubella to their offspring, which can be fatal and can result in congenital rubella syndrome (CRS). The traditional centralized model for diagnosing rubella is cost-prohibitive in resource-limited settings, representing a major obstacle to the prevention of CRS. As a step toward decentralized diagnostic systems, we developed a proof-of-concept digital microfluidic (DMF) diagnostic platform that possesses the flexibility and performance of automated immunoassay platforms used in central facilities, but with a form factor the size of a shoebox.
  
  
  METHODS
  DMF immunoassays were developed with integrated sample preparation for the detection of rubella virus (RV) IgG and IgM. The performance (sensitivity and specificity) of the assays was evaluated with serum and plasma samples from a commercial antirubella mixed-titer performance panel.
  
  
  RESULTS
  The new platform performed the essential processing steps, including sample aliquoting for 4 parallel assays, sample dilution, and IgG blocking. Testing of performance panel samples yielded diagnostic sensitivity and specificity of 100% and 100% for both RV IgG and RV IgM. With 1.8 μL sample per assay, 4 parallel assays were performed in approximately 30 min with <10% mean CV.
  
  
  CONCLUSIONS
  This proof of concept establishes DMF-powered immunoassays as being potentially useful for the diagnosis of infectious disease.
authors.affiliation: Institute of Biomaterials and Biomedical Engineering, Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada;
authors.forename: Alphonsus H C
authors.initials: AH
authors.lastname: Ng
authors.affiliation: Innis College, and Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada;
authors.forename: Misan
authors.initials: M
authors.lastname: Lee
authors.affiliation: Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada; Department of Chemistry, University of Toronto, Toronto, ON, Canada;
authors.forename: Kihwan
authors.initials: K
authors.lastname: Choi
authors.affiliation: Abbott Diagnostics, Irving, TX;
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Fischer
authors.affiliation: Abbott Diagnostics, Abbott Park, IL.
authors.forename: John M
authors.initials: JM
authors.lastname: Robinson
authors.affiliation: Institute of Biomaterials and Biomedical Engineering, Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada; Department of Chemistry, University of Toronto, Toronto, ON, Canada; aaron.wheeler@utoronto.ca.
authors.forename: Aaron R
authors.initials: AR
authors.lastname: Wheeler
mesh_terms: D000914:Antibodies, Viral / Q000097:blood* / Q000276:immunology; D004867:Equipment Design; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D007074:Immunoglobulin G / Q000097:blood* / Q000276:immunology; D007075:Immunoglobulin M / Q000097:blood* / Q000276:immunology; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D011247:Pregnancy; D012409:Rubella / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D012412:Rubella virus / Q000276:immunology* / Q000302:isolation & purification; D012680:Sensitivity and Specificity
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G; D007075:Immunoglobulin M