The project “DeDNAed” intends to develop a novel, innovative biosensing platform whose advantages and benefits are in terms of sensitivity, versatility and being ultrafast by an optical approach. Our platform will be based on the assembly and integration of sensing elements (transducer and bioreceptor) by DNA origami. The DNA origami will serve as a “nano-breadboard” in order to precisely control the position of these elements and thus the sensor architecture at the nanometer scale.
Figure 1: Schematic formation of fluorescent DNA-hosted Au-nanoclusters and the hairpin DNAs,
single-stranded DNAs and fully matched DNAs.
Metallic atomic clusters (ACs) are integrated into a biological marker molecule (DNA or antibody) and thus represent the biological sensor element (Fig. 1). This is specifically integrated into a nanoarray, made of additional metallic nanoparticles, precisely controlled by a DNA origami template and will lead to a significant increase in signal. The DNA origami serves as an individually, inter- and intramolecularly programmable “nano-breadboard”. A DNA origami consists of a single strand of DNA, folded by a thermal treatment and certain staple strands into any shapes (2D as well as 3D, dimensions of approx. 100 nanometers). So-called “sticky ends” on the surface of the DNA origami offer the possibility of an individual implementation of the sensing elements and nanoparticles, by means of correspondingly complementary oligonucleotides with a resolution of approx. 2 nm. When the analyte is connected to the sensor element, a change in the Raman signal can thus be detected without major delay using surface-enhanced Raman spectroscopy (SERS), as depicted in Fig.2.
Figure 2: Schematic sketch of the change in the SERS signal upon binding of the analyte to the biological marker molecule (e.g. DNA aptamer).
This sensor method is not bound to a specific biomarker molecule for the sensor element, but can be transferred to different marker molecules. This results in a high degree of flexibility in the area of application, from medical technology to food monitoring. In addition, a transfer of the DNA origami-based sensor platform to flexible, textile substrates is carried out using lipid bi-layers and the Langmuir-Blodgett method for later use as a wipe test or medical wearable (Fig. 3).
Figure 3: Schematic sketch of the large scale arrangement of DNA origami based sensor array on supporting lipid-bilayers (SLB) anchored by cholesterol units and the transfer mechanism to flexible substrate by LB.