Dielectric Nanoantennas Enhance Fluorescence in Single-Molecule Spectroscopy.

The study investigates dielectric nanoantennas as an alternative to metallic ones, addressing their high ohmic losses. Using DNA origami, silicon nanoparticles were positioned near organic fluorophores at the single molecule level across visible wavelengths. Fluorescence intensity and lifetime measurements revealed significant decay rate modifications with minimal quenching and high yield even at short distances. This demonstrates dielectric nanoantennas’ advantages over metallic counterparts, highlighting their potential for single-molecule spectroscopy applications.

The study of optical nanoantennas has revolutionized our understanding of light-matter interactions at the nanoscale. While metallic nanostructures have traditionally dominated this field due to their exceptional electric field enhancement capabilities, they are constrained by significant ohmic losses. In response, researchers have turned to high-refractive-index dielectrics as a promising alternative, offering negligible ohmic losses and supporting both electric and magnetic resonances in the visible and near-infrared range.

A collaborative effort led by Nicole Siegel from the University of Fribourg, along with María Sanz-Paz from Sorbonne Université and colleagues from various institutions including the University of Cantabria, CONICET, and Kobe University, explores this innovative approach. Their research employs DNA origami to investigate the interaction between silicon nanoparticles and organic fluorophores at the single molecule level. This method allows for precise control over geometries and spectral ranges within the visible spectrum.

The findings reveal significant modifications in fluorescence decay rates with minimal quenching and a high fluorescence yield, even at short distances from the dielectric nanoparticle. Titled Distance dependent interaction between a single emitter and a single dielectric nanoparticle using DNA origami, this study underscores the advantages of dielectric nanoantennas over metallic counterparts, opening new avenues for applications in single-molecule spectroscopy.

This research not only highlights the potential of dielectric materials but also demonstrates the effectiveness of DNA origami as a tool for precise nanoscale studies. The collaborative work represents a significant step forward in advancing our understanding and application of optical nanoantennas.

Proximity to SiNPs enhances fluorescence in dye interactions.

The article investigates the interaction between fluorescent emitters (ATTO 542 and ATTO 647N dyes) and silicon nanoparticles (SiNPs) using DNA origami structures. The setup involves placing these emitters at varying distances from a SiNP with a radius of 70 nm on a glass substrate functionalized with neutravidin, which binds biotinylated DNA staples. These staples are part of the DNA origami structures that include fluorescent emitters and PolyA handles for capturing SiNPs.

The study measures electric field enhancement at two excitation wavelengths (532 nm and 635 nm), showing varying enhancement values depending on the distance from the SiNP. For instance, at 532 nm, enhancement ranges from 0.88 to 1.63. Collection efficiency, which assesses how well emitted light is collected, varies between dyes: ATTO 542 has an efficiency range of 0.82 to 0.93, while ATTO 647N ranges from 0.91 to 0.94.

Quantum yield analysis reveals that proximity to the SiNP increases emission efficiency, suggesting enhanced energy transfer or radiative decay. The study also examines radiative (k_r) and non-radiative (k_nr) decay rates, highlighting the impact of distance on these processes.

The DNA staples used are detailed in Table S3, with sequences modified for fluorescent emitters and PolyA handles. Additional sequence details are provided in Table S4. Key findings include significant fluorescence enhancement near SiNPs due to electric field effects, with dipole orientation (in-plane vs. out-of-plane) affecting results. Increased quantum yield with proximity indicates efficient energy transfer.

The research builds on prior work referenced in Table S4, contributing to existing knowledge on DNA origami and nanoparticle interactions. This study underscores the importance of distance and orientation in fluorescence enhancement, with implications for applications like sensing and imaging.

DNA origami positions fluorescent dyes near SiNPs for enhanced fluorescence.

The research integrates DNA origami structures with silicon nanoparticles (SiNPs) to enhance fluorescence by strategically positioning fluorescent dyes near the SiNPs, which act as optical antennas. The study demonstrates that the placement of the dye relative to the SiNP significantly impacts fluorescence efficiency, with optimal positions yielding higher enhancement values. This precise control over dye placement is achieved through a DNA origami design that uses specific staples and PolyA sequences to attach the dyes at designated locations (P1-P3) near the SiNP.

The research also highlights the importance of collection efficiency, which remains robust (0.82-0.94) across various distances from the SiNP, indicating that fluorescence enhancement is relatively insensitive to minor positional variations. Simulation validation confirms the accuracy of the experimental results by comparing them with modeled quantum yield and decay rates, showing good agreement and supporting the reliability of the approach.

The mechanism behind the enhanced fluorescence involves increased local electric field strength at the dye’s location, which amplifies both excitation and emission efficiency. This innovation enables applications such as improved sensing with low concentration detection and reduced background noise through directional signal discrimination. The combination of nanotechnology and DNA engineering allows for precise manipulation of light at the nanoscale, offering practical implications in fields like sensing and imaging.

DNA origami modifications enhance functionality with fluorescent markers and PolyA extensions.

The study investigates modifications to DNA staple sequences for enhanced functionality in origami structures. Specifically, the research introduces fluorescent molecules (ATTO 647N and ATTO 542) at positions P1, P2, and P3 to enable precise tracking of these staples within the structure. Additionally, biotinylated staples are utilized to facilitate binding to a neutravidin-functionalized glass surface, enhancing the stability and anchoring capabilities of the origami framework.

Furthermore, the study extends DNA staple sequences with PolyA segments (varying in length) to serve as handles for capturing single PolyT-functionalized silicon nanoparticles (SiNPs). This modification allows for targeted integration of SiNPs into the origami structure, potentially enabling applications in nanotechnology and material science.

The findings demonstrate that these modifications effectively enhance both the functionality and versatility of DNA origami structures. Future research could explore optimizing the efficiency of SiNP capture or investigating alternative DNA extensions to further expand the potential applications of this technology.

DNA origami enhances fluorescence for biosensing and imaging.

The study demonstrates that DNA origami structures effectively position dye molecules relative to silicon nanoparticles (SiNPs), enhancing fluorescence through directional antenna effects. Key findings include optimal positioning at specific distances (d2 and d3) for maximum electric field enhancement at wavelengths 532 nm and 635 nm, respectively. Higher collection efficiency was observed when emitters were positioned farther from the SiNP, with slight variations depending on dye type. The experimental results align well with simulations, confirming the reliability of their model.

The research highlights potential applications in biosensing for improved sensitivity in low-concentration scenarios and enhanced imaging techniques for clearer target visualization. Additionally, surface immobilization via biotin-neutravidin suggests broader applicability in device integration.

Future work could explore alternative nanoparticles or configurations to further optimize fluorescence enhancement. Testing under physiological conditions would also be valuable for advancing biomedical applications.