High‐Yield Assembly of Plasmon‐Coupled Nanodiamonds Using DNA Origami for Tuned Emission
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2025-09-27 |
| Journal | Small Structures |
| Authors | Niklas Hansen, Jakub Čopák, Marek Kindermann, David Roesel, Federica Scollo |
| Institutions | University of Chemistry and Technology, Prague, Czech Academy of Sciences, Institute of Organic Chemistry and Biochemistry |
| Citations | 2 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled “Executive Summary”This research presents a robust, high-yield strategy for assembling plasmon-coupled nanodiamonds (NDs) containing nitrogen-vacancy (NV) centers onto DNA origami platforms, enabling precise control over quantum emitter properties.
- Core Innovation: A scalable, covalent DNA functionalization method for fluorescent nanodiamonds (FNDs) was developed, ensuring robust binding and colloidal stability in high-ionic-strength electrolytes necessary for DNA origami assembly.
- High Assembly Yield: Optimized binding site design (“extended” configuration) achieved assembly yields exceeding 50% for FND-DNA origami hybrids, overcoming limitations of previous non-specific binding methods.
- Plasmonic Tuning Demonstrated: Successful integration of FNDs and gold nanoparticles (AuNPs) into hybrid structures allowed systematic investigation of distance-dependent plasmon-NV coupling.
- Lifetime Modulation: The NV center photoluminescence (PL) intensity-weighted average lifetime (Tavg) was significantly reduced from 27.0 ns (bare FND) down to 15.0 ns in the closest configuration (35 nm center-to-center spacing).
- Purcell Enhancement: A maximum Purcell factor (FP) enhancement of 1.8 was achieved, indicating efficient coupling between the NV excited states and localized surface plasmons.
- Selective Decay Enhancement: Analysis revealed a substantial increase in the contribution of the fastest decay component (T3), suggesting selective enhancement of specific decay pathways crucial for fast light-matter interactions.
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value | Unit | Context |
|---|---|---|---|
| ND Average Diameter (davg) | 40 | nm | Starting material for FND preparation. |
| DNA Origami Structure | 12-helix bundle (12HB) | - | Length approx. 200 nm; diameter approx. 10 nm. |
| NV Center Fabrication (Electron Beam) | 6.6 | MeV | Electron beam energy used for NV creation. |
| NV Center Annealing Temperature | 900 | °C | Annealing performed under Argon atmosphere. |
| FND DNA Loading Density | 198 ± 6 | Oligonucleotides/FND | Achieved via covalent SPAAC conjugation. |
| AuNP Diameter (Tested) | 20, 40 | nm | Used for plasmonic coupling. |
| Interparticle Spacing (Center-to-Center) | 35, 70, 140 | nm | Precisely controlled by DNA origami design. |
| Maximum Assembly Yield | 58 | % | Achieved for FND-origami using “extended” binding sites. |
| Bare FND Average Lifetime (Tavg) | 27.0 ± 0.5 | ns | DNA-coated NDs reference value. |
| Closest Assembly Tavg (40 nm AuNP, 35 nm) | 15.0 ± 0.1 | ns | Maximum observed PL lifetime reduction. |
| Maximum Purcell Factor (FP) | 1.8 | - | Calculated for 35 nm interparticle distance. |
| Fastest Decay Component (T3) Contribution | ~40 | % | Observed in the 35 nm close assembly configuration. |
| Electrolyte Concentration (Assembly) | 1x TAE, 10 | mM | MgCl2 concentration for DNA origami stability. |
Key Methodologies
Section titled “Key Methodologies”The assembly relies on a three-step FND functionalization process followed by sequential hybridization onto the DNA origami platform.
- DNA Origami Synthesis: 12-helix bundles (12HB) were synthesized by mixing M13mp18 scaffold with staple strands (1:10 molar ratio). Hybridization involved incubation for approximately 25 h in 1x TAE buffer containing 15 mM MgCl2, followed by purification using 100 kDa MWCO centrifugal filters.
- AuNP Functionalization: Citrate-capped AuNPs (20 nm and 40 nm) were treated with bis(p-sulfonatophenyl)phenylphosphine (BSPP) and subsequently conjugated with monothiolated ssDNA (T21 sequence). A salt-aging procedure (up to 0.75 M NaCl) was used to ensure dense oligonucleotide coverage and stability.
- FND Surface Modification (Silication): FNDs were coated with an ultrathin silica layer using tetraethylorthosilicate (TEOS) and (trimethoxysilyl)propyl methacrylate (TMSPMC) in the presence of polyvinylpyrrolidone (PVP).
- FND Surface Modification (Polymer Coating): Silicated FNDs were coated with an azide-functionalized copolymer layer consisting of N-(2-hydroxypropyl)methacrylamide (HPMA) and N-(3-azidopropyl)methacrylamide (AzMA) via “grafting through” polymerization at 55 °C under an Argon atmosphere for 72 h.
- FND DNA Conjugation (SPAAC): DBCO-modified DNA strands were covalently attached to the azide groups on the FND surface via Strain-Promoted Azide-Alkyne Cycloaddition (SPAAC). The reaction was run for 21 days at 45 °C to ensure high conjugation yield.
- Hybrid Assembly: FNDs were first hybridized to the 12HB origami (1:2 molar ratio) by annealing from 48 °C down to RT. Freshly purified AuNPs were then added (1:1 molar ratio relative to origami) and incubated at RT for 90 min.
- Purification and Analysis: Assemblies were purified using 0.7% agarose gel electrophoresis. Successful structures were identified and analyzed by correlating Atomic Force Microscopy (AFM) images with Fluorescence Lifetime Imaging (FLIM) measurements on a composite mica/glass substrate.
Commercial Applications
Section titled “Commercial Applications”This technology enables the creation of precisely structured nanoscale hybrid devices, advancing fields that rely on controlled light-matter interaction and quantum properties.
- Quantum Sensing: Development of highly sensitive, spatially resolved sensors for magnetic, electric, and thermal phenomena, utilizing the enhanced spin-state readout rates enabled by plasmonic coupling.
- Quantum Computing and Photonics: Fabrication of solid-state qubits and nanoscale photonic circuits where NV centers are integrated with plasmonic waveguides for controlled energy transfer and optical signal routing.
- Nanoscale Probes: Creation of robust, photostable local probes for dynamic live cell imaging and sensing of molecular interactions in heterogeneous environments.
- Plasmon-Enhanced Spectroscopy: Devices designed to maximize the Purcell effect for tailored emission properties, potentially leading to enhanced single-photon emission rates and ultrafast radiative decay.
- Biomedical Diagnostics: The DNA origami platform can be extended to incorporate biomolecules, enabling targeted biosensing applications using the NV center as a highly sensitive reporter.
View Original Abstract
Controlling the spatial arrangement of optically active elements is crucial for the advancement of engineered photonic systems. Color centers in nanodiamonds (NDs) offer unique advantages for quantum sensing and information processing; however, their integration into complex optical architectures is limited by challenges in precise and reproducible positioning, as well as efficient coupling. DNA origami provides an elegant solution, as demonstrated by recent studies that showcase the nanoscale positioning of fluorescent NDs and plasmonic gold nanoparticles (NPs). A scalable and robust method is presented for covalently functionalizing NDs with DNA, enabling a high‐yield and spatially controlled assembly of diamond and gold NPs onto DNA origami. By precisely controlling the interparticle spacing, this approach reveals the distance‐dependent modulation of a nitrogen‐vacancy (NV) center photoluminescence (PL). These findings indicate selective plasmon‐driven effects. This work overcomes key limitations in current nanodiamond assembly strategies and provides insights into engineering NV PL by plasmonic coupling. These advancements bring closer to quantum photonic and sensing applications.