A combined magnetophoresis/dielectrophoresis based microbead array as high-throughput biomolecular tweezers

In this paper we describe a combined magnetophoresis (MAP) and dielectrophoresis (DEP) based platform for high throughput characterization of specific biomolecular interactions. The magnetic manipulation enables parallel loading of individual magnetic beads onto a magnetic pad array, while the combination of tightly controlled opposing magnetic and dielectrophoretic (DEP) forces is employed to produce characteristic out-of-plane (z-axial) bead displacement. We optimized design parameters to evenly load 2.8 μm biomolecule functionalized paramagnetic beads onto magnetic pads, and demonstrate the ability of our tweezers to discriminate between specific antibody-antigen bond from non-specific bond formed between bead and pad surface.

Evaluation of Influenza-Specific Humoral Response by Microbead Array Analysis

RATIONALE: Quantitation and determination of antigen specificity of systemic and mucosal immune responses to influenza vaccination is beneficial for future vaccine development. Previous methods to acquire this information were costly, time consuming and sample exhaustive. The benefits of suspension microbead array (MBA) analysis are numerous. The multiplex capabilities of the system conserve time, money and sample, while generating statistically powerful data.OBJECTIVE: To demonstrate the use of the assay by comparing the humoral influenza-specific responses of two cohorts from two countries that differed in circulating influenza strains and rates of influenza vaccination.METHODS: Influenza hemagglutinin (HA) from different strains were coated on microbeads and incubated with serum samples to capture immunoglobulin (Ig) A1and IgG1host antibodies.RESULTS: Statistically significant differences in IgA1and IgG1exist between the serum samples from Winnipeg (Manitoba) donors and those from Kenyan (Africa) donors. Data were compared using Mann-Whitney nonparametric tests. The Winnipeg donors had higher mean fluorescence intensity values, with significant P values for anti-HA IgA1to A/Wyoming/3/2003 (P=0.044), A/Vietnam/1203/2004 (P=0.0179), A/New Caledonia/20/99 (P<0.0001) and B/Tokyo/53/99 (P=0.0002). No differences were seen between the groups in their response to B/Jilin/20/2003. The Winnipeg donors had higher mean fluorescence intensity values, with significant P values for anti-HA IgG1to A/Wyoming/3/2003 (P=0.0135), B/Tokyo/53/99 (P=0.006) and B/Jilin20/2003 (P=0.026).CONCLUSION: Influenza-specific IgA1and IgG1antibodies were successfully detected using MBA technology. A significant difference in antibody response was observed between Winnipeg and Kenyan donor serums. MBA analysis is a relatively quick and cost-effective method for serum antibody analysis. The potential to simultaneously assay small sample volumes for a multitude of antigens makes this method invaluable for future vaccine response monitoring.