A curved top-wall flow cell for improvement of response consistency in surface plasmon resonance array detection

• A curved top-wall flow cell is proposed to improve the response consistency in SPR array detection.
• A universal mathematical relation between the mass transport rate and the flow cell height was established and the optimal flow cell geometry for analyte distribution uniformity was derived.
• The actual flow regimes within the novel flow cell were confirmed by micro-PIV experiments and results agreed with expectations.
• Goat-anti-rabbit IgG and rabbit IgG interaction experiments were performed on a SPR imaging system using both the novel and conventional flow cells.
• The novel flow cell significantly reduced the coefficient of variance of association rate across the sensing surface.

High spatially consistent responses are desired for the array-based biomolecular interaction analysis. The response consistency is dependent on the uniformity of mass transport rate. Based on theoretical analysis, we established a universal mathematical relation between the mass transport rate and the flow cell height. The optimal flow cell geometry for analyte distribution uniformity, H(l) = 1/3 · l−1/2, was derived from the mathematical relation. Using Poly(dimethylsiloxane) elastomer replica molding methods, the flow cell was fabricated. The actual flow regimes within the flow cell were confirmed by micro-PIV experiments and results agreed with expectations. To demonstrate the capability of this flow cell in improving spatial consistency of responses, goat-anti-rabbit IgG and rabbit IgG interaction experiments were performed on a home-built SPR imaging system. Results showed that the curved top-wall flow cell significantly reduced the coefficient of variance of association rate across the sensing surface.