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DNA self-assembled optical nano-antennas for single photon emitters. Directing and concentrating light for future diagnostic platforms

English title DNA self-assembled optical nano-antennas for single photon emitters. Directing and concentrating light for future diagnostic platforms
Applicant Acuna Guillermo Pedro
Number 184687
Funding scheme Project funding (Div. I-III)
Research institution Département de Physique Université de Fribourg
Institution of higher education University of Fribourg - FR
Main discipline Condensed Matter Physics
Start/End 01.10.2019 - 30.09.2023
Approved amount 1'053'869.00
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All Disciplines (2)

Discipline
Condensed Matter Physics
Physical Chemistry

Keywords (9)

Colloidal-nanoparticles; Enhanced-spectroscopy-techniques; high-index-dielectric nanoparticles; point-of-care-devices; Plasmonics; DNA-nanotechnology; DNA-origami; Optical-Antennas; Nanophotonics

Lay Summary (German)

Lead
Nanometergroße optische Antennen können analog zu ihren makroskopischen Vertretern in der Hochfrequenztechnik dazu verwendet werden, um elektromagnetische Signale im Nanometermaßstab zu manipulieren. Dies ermöglicht die gezielte Wechselwirkung zwischen Photonen und einzelnen Molekülen. Die Herstellung dieser Antennen wird gegenwärtig mittels aufwendiger Top-Down-Verfahren realisiert. Allerdings unterliegen diese Verfahren verschiedenen Beschränkungen wie zum Beispiel der Wahl des Substrats oder Materialkombinationen. Die gezielte räumliche und stöchiometrische Anordnung bspw. einzelner (Bio-)Moleküle ist dabei nahezu unmöglich.
Lay summary

Im Gegensatz dazu schlagen wir einen Bottom-Up-Ansatz basierend auf DNA-Nanotechnologie vor, der nicht nur die definierte räumliche Anordnung von Zielstrukturen, sondern auch, bedingt durch seine hochgradige Parallelisierung, die gleichzeitige Herstellung mehrerer Milliarden dieser Antennenstrukturen in nur einem Ansatz ermöglicht. Im Anschluss daran sollen diese aufgebauten optischen Antennen hinsichtlich folgender drei Aspekte charakterisiert und optimiert werden:

  1. Kontrolle der Emissionsrichtung der molekularen Fluoreszenz
  2. Einheitlichkeit der Leistung in Bezug auf die Fluoreszenzverstärkung
  3. Optimierung der Signalverstärkung und Richtwirkung des Fluoreszenzsignals

Im Vergleich mit theoretischen Betrachtungen tragen diese Arbeiten zu einem weiterführenden Verständnis hinsichtlich hoch gerichteter Einzelphotonenquellen bei, die auch Gegenstand der Untersuchungen im Bereich optischer Kommunikation sind. Darüber hinaus sollen die gewonnenen Erkenntnisse dazu verwendet werden, um hoch sensitive diagnostische Assays für Einzelmoleküluntersuchungen zu entwickeln und diese mit herkömmlichen Handheld-Geräten, wie zum Beispiel Smartphones, zu kombinieren.

Direct link to Lay Summary Last update: 08.04.2019

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Abstract

Radiofrequency and microwave antennas are extensively used to manipulate electromagnetic radiation of large wavelengths (cm to km) and couple it to smaller devices and circuits (cm to mm). Efficient interaction of light with molecules is challenging due to a similar size mismatch: 400-800 nm wavelength to ~1 nm molecular size. In analogy to their larger counterparts, optical nano-antennas (ONAs) have been developed to manipulate light at the nanoscale and thereby improve the interaction between photons and single molecules. So far, most ONAs have been fabricated using top-down nanofabrication as electron beam lithography or ion beam milling. Such an approach has been successful to test the fundamental working principles of ONAs but presents a number of limitations for certain applications. Fabrication is serial (slow) and requires costly equipment. It is limited to ONAson substrates. Combination of more than two materials is highly challenging, especially in 3D. Conjugation to (bio-)molecules on specific positions of the ONA with controlled stoichiometry is virtually impossible.Recently, we have pioneered a new approach that exploits DNA nanotechnology to produce ONAs that overcome all these limitations. In particular, we apply the DNA origami technique to organize metallic nanoparticles (NPs) and (bio-)molecules in well-defined nanometric geometries and stoichiometry ratios. In this way, zillions of ONAs self-assemble in parallel in one or a few simple steps.In this project, we will fabricate and characterize a variety of DNA self-assembled ONAs with three objectives: i) control the emission direction of molecular fluorescence; ii) obtain ensembles of ONA with uniform performance in terms of fluorescence enhancement; and iii) obtain a configuration of both strong enhancement and directionality of fluorescence signals into the detectors in order to develop extremely sensitive diagnostic assays that could be read-out in personal devices. Based on our previous work and preliminary numerical simulations, we expect to achieve unidirectional emission of single molecules (with a directivity of approximately four, which translates into four times more emitted power in its peak direction as compared to isotropic antennas), together with a fluorescence intensity enhancement of more than three orders of magnitude. These advancements will boost the detection sensitivity of personal devices, e.g. based on smartphones, to the ultimate detection level of single molecules enabling portable diagnostic kits.The main expected impact of this project resides on the potential of enhancing optical signals of bio-assays to the level of making personal portable devices equivalent to current high-end medical diagnostics machines. This in turn would signify a breakthrough for personalized medicine and point-of-care testing platforms for mobile healthcare.As an additional impact, we expect our ONAs, based on colloidal (and monocrystalline) NPs and single molecules self-assembled with nanometer precision and stoichiometric control, to exhibit a highly reproducible performance. This facilitates a faithful comparison to theoretical predictions which will deepen our understanding of nanophotonics in general and of highly directional on demand single photon sources for optical communication in particular.
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