Université de Fribourg

DNA origami as emerging technology for the engineering of fluorescent and plasmonic-based biosensors

Loretan, Morgane ; Domljanovic, Ivana ; Lakatos, Mathias ; Rüegg, Curzio ; Acuna, Guillermo P.

In: Materials, 2020, vol. 13, no. 9, p. 2185

DNA nanotechnology is a powerful and promising tool for the development of nanoscale devices for numerous and diverse applications. One of the greatest potential fields of application for DNA nanotechnology is in biomedicine, in particular biosensing. Thanks to the control over their size, shape, and fabrication, DNA origami represents a unique opportunity to assemble dynamic and complex...

Université de Fribourg

Directing single-molecule emission with dna origami-assembled optical antennas

Hübner, Kristina ; Pilo-Pais, Mauricio ; Selbach, Florian ; Liedl, Tim ; Tinnefeld, Philip ; Stefani, Fernando D. ; Acuna, Guillermo P.

In: Nano Letters, 2019, vol. 19, no. 9, p. 6629–6634

We demonstrate the capability of DNA self-assembled optical antennas to direct the emission of an individual fluorophore, which is free to rotate. DNA origami is used to fabricate optical antennas composed of two colloidal gold nanoparticles separated by a predefined gap and to place a single Cy5 fluorophore near the gap center. Although the fluorophore is able to rotate, its excitation and...

Université de Fribourg

DNA‐mediated self‐assembly of plasmonic antennas with a single quantum dot in the hot spot

Nicoli, Francesca ; Zhang, Tao ; Hübner, Kristina ; Jin, Boyuan ; Selbach, Florian ; Acuna, Guillermo P. ; Argyropoulos, Christos ; Liedl, Tim ; Pilo-Pais, and Mauricio

In: Small, 2019, vol. 15, no. 26, p. 1804418

DNA self‐assembly is a powerful tool to arrange optically active components with high accuracy in a large parallel manner. A facile approach to assemble plasmonic antennas consisting of two metallic nanoparticles (40 nm) with a single colloidal quantum dot positioned at the hot spot is presented here. The design approach is based on DNA complementarity, stoichiometry, and steric hindrance...

Université de Fribourg

Distance dependence of single-molecule energy transfer to graphene measured with DNA origami nanopositioners

Kaminska, I. ; Bohlen, J. ; Rocchetti, S. ; Selbach, F. ; Acuna, Guillermo P. ; Tinnefeld, P.

In: Nano Letters, 2019, vol. 19, no. 7, p. 4257–4262

Despite the thorough investigation of graphene since 2004, altering its surface chemistry and reproducible functionalization remain challenging. This hinders fabrication of more complex hybrid materials with controlled architectures, and as a consequence the development of sensitive and reliable sensors and biological assays. In this contribution, we introduce DNA origami structures as...

Université de Fribourg

Plasmon-assisted Förster resonance energy transfer at the single-molecule level in the moderate quenching regime

Bohlen, J. ; Cuartero-González, Á. ; Pibiri, E. ; Ruhlandt, D. ; Fernández-Domínguez, A. I. ; Tinnefeld, P. ; Acuna, Guillermo P.

In: Nanoscale, 2019, vol. 11, no. 16, p. 7674–7681

Metallic nanoparticles were shown to affect Förster energy transfer between fluorophore pairs. However, to date, the net plasmonic effect on FRET is still under dispute, with experiments showing efficiency enhancement and reduction. This controversy is due to the challenges involved in the precise positioning of FRET pairs in the near field of a metallic nanostructure, as well as in the...

Université de Fribourg

Benchmarking smartphone fluorescence-based microscopy with DNA origami nanobeads: reducing the gap toward single-molecule sensitivity

Vietz, Carolin ; Schütte, Max L. ; Wei, Qingshan ; Richter, Lars ; Lalkens, Birka ; Aydogan Ozcan ; Tinnefeld, Philip ; Acuna, Guillermo P.

In: ACS Omega, 2019, vol. 4, no. 1, p. 637–642

Smartphone-based fluorescence microscopy has been rapidly developing over the last few years, enabling point-of-need detection of cells, bacteria, viruses, and biomarkers. These mobile microscopy devices are cost-effective, field-portable, and easy to use, and benefit from economies of scale. Recent developments in smartphone camera technology have improved their performance, getting closer...