Sprecher
Beschreibung
We develop a colorimetric sensing platform compatible with single-molecule detection by assembling gold-nanosphere dimers on a Y-shaped DNA origami that acts as a nanoscale actuator (Fig.1-a). DNA origamis are a highly programmable and flexible platform that can be precisely engineered to undergo controlled conformational changes in response to specific molecular targets, such as DNA/RNA strands, proteins, or specific cations [1]. To translate such conformational changes in colorimetric information, we exploit the nanoscale dependence of plasmon coupling between two gold nanospheres [2,3].
The scaffold of our DNA origami features an active site with a conformation that can be tuned by hybridizing specific DNA single strands (Fig. 1-b). One-step digital colorimetric sensing of DNA single strands is achieved using a strand displacement reaction. These measurements are carried out both by performing single-nanostructure scattering spectroscopy (Fig.1-c) and by analyzing the hue of single dimers in dark-field images (Fig.1-d), obtaining similar statistical responses. The kinetics of these single DNA sensing events are monitored as a function of the concentration of the target strands (Fig. 1-e) and by introducing one or two base mismatches in the DNA sequence to characterize the sensitivity and specificity of these hybrid nanosensors. These results highlight the versatility of DNA origamis for colorimetric sensing, in particular to monitor single DNA or RNA strands on a simple color camera.
[1] Y. Ke et al., Nat. Commun, 7:10935, 2016
[2] L. Lermusiaux et al., ACS Nano, 9:978, 2015
[3] L. Lermusiaux et al., Langmuir, 34:14946, 2018
