Fig. 5

Remazol Brilliant Blue Nanotrap particles show the highest affinity for OspA among the tested dyes. a Nanotrap particles Lyme antigen (1 ng) was spiked in 500 µL of human urine from healthy volunteers and incubated with Nanotrap particles functionalized with different dyes. After Nanotrap particles processing, Lyme antigen is successfully depleted from supernatants (S) and easily detectable in the eluate (E). Lanes 1 ladder; 2 Lyme antigen 0.1 ng; 3 Supernatant Remazol Brilliant Blue Nanotrap 1; 4 Eluate Remazol Brilliant Blue Nanotrap 1; 5 Supernatant Remazol Brilliant Blue Nanotrap 2; 6 Eluate Remazol Brilliant Blue Nanotrap 2; 7 Supernatant Reactive Blue 4 Nanotrap; 8 Eluate Reactive Blue 4 Nanotrap; 9 Supernatant Diamine Green Nanotrap; 10 Eluate Diamine Green Nanotrap. b Nanotrap particles without dye bait can volume sequester some antigen but not concentrate the analyte from the surrounding solvent volume, in absence of affinity capture. The amount of OspA in the dye free particles is approximately 10 % of the control solution reflecting the urine solution/Nanotrap particle volumetric ratio (10:1). Lanes 1 ladder; 2 Lyme antigen 1 ng; 3 Negative control = urine without Bb antigen, 4 Supernatant vinyl phenyl boronic acid Nanotrap 1; 5 Eluate vinyl phenyl boronic acid Nanotrap 2; 6 Supernatant acrylic acid Nanotrap; 7 Eluate acrylic acid Nanotrap; 8 Supernatant allylamine Nanotrap; 9 Eluate allylamine Nanotrap; 10 Supernatant Remazol Brilliant Blue Nanotrap; and 11 Eluate Remazol Brilliant Blue Nanotrap. c Relationship between the Remazol Brilliant Blue in the particles and depletion of the antigen in the supernatant: 100 % antigen depletion from the solution phase and saturation of binding. Lane 1 ladder, lane 2 initial solution, lanes 3–7 supernatants after incubation of a urine solution containing 0.6 ng of Bb antigen with Nanotrap particles functionalized with increasing concentration of Remazol Briliant blue: 34, 68, 171, 343, 686 n moles, respectively. d ImageJ quantification of the optical density in (c). Y axis: Antigen sequestered in the Nanotrap particles obtained as difference between the initial solution (lane 2) and the supernatants (lanes 3–7) in (c). X axis: μ moles of Remazol Brilliant blue in the Nanotrap particles