Fig. 2: DNA origami and LFIA test design.

a A schematic presentation of the design of a DNA origami 6HB with an adjustable number of binding domains (dark blue) and one amplification domain (light blue). For LFIAs, antibodies are attached to the binding domains. DNA-conjugated labels, such as gold nanoparticles or fluorophores, bind to the amplification domain. b Transmission electron microscopy (TEM) image of a detection antibody-6HB conjugate (Ab-6HB) after incubation of 6HBs with a 6-fold molar excess of DNA-conjugated detection antibodies (Ab-DNA) and gel purification. The bound antibodies are indicated by arrows (scale: 100 nm). c Decoration of the 6HBs with labels. The TEM image in the left panel shows a 6HB after incubation with DNA-labeled gold nanoparticles; here, 20-nm particles for the purpose of demonstration (scale: 100 nm). The right panel shows an agarose gel electrophoresis (AGE) analysis of SYBR Safe DNA stain and Alexa Fluor 647 (A647) fluorescence of 6HBs after incubation with a 200-fold molar excess of A647-labeled oligonucleotides. d A general design of a LFIA test used for the integration of DNA origami signal amplification. e LFIA running protocol. The amplified signal is generated when the sample-DNA origami mixture interacts with both the labels and the immobilized antibodies on the test (T) and control (C) lines. Source data for panels b and c are provided as a Source Data file.