DNA Self-Assembled Plasmonic Nanodiamonds for Biological Sensing

Abstract

Nitrogen-vacancy (NV) centers in diamonds are promising solid-state quantum emitters for developing superior biological imaging modalities. They possess desired bio-compatibility, photostability and electronic spin-related photophysical properties that are optically accessible at room temperature. Yet, bare nanodiamond-based imaging modalities are limited by the brightness and temporal resolution due to the intrinsically long lifetime of NV centers. Moreover, it remains a technological challenge using top-down fabrication to create freestanding hybrid nanodiamond imaging probes with enhanced performance. In this study, we leverage the bottom-up DNA self-assembly to develop a hybrid plasmonic nanodiamond construct, which we coin as the plasmon-enhanced nanodiamond (PEN), for biological imaging. The PEN nano-assembly features a closed plasmonic nanocavity that completely encapsulates a single nanodiamond, thus enabling the largest possible plasmonic enhancement to accelerate the emission dynamics of NV centers. Creation of the PEN nano-assembly is size-independent, so is its broadband scattering spectrum that is optimally overlapped with the emission spectrum of NV centers. Study of the structure-property correlation reveals that the optimal condition for emission dynamics modification is causally linked to that for a plasmonic nanocavity. The cellular internalization and cytotoxicity studies further confirm the delivery efficiency and biological safety of PEN nano-assemblies. Collectively, the PEN nano-assembly provides a promising approach for manipulating photophysical properties of solid-state quantum emitters and could serve as a versatile platform to uncover non-trivial quantum effects in biological systems.

Recent Development of Fluorescent Nanodiamonds for Optical Biosensing and Disease Diagnosis

“…The sensing spin protocols were optimized to achieve the maximum NMR sensitivity to sufficiently detect chemical shifts ( 1 H and 19 F) in a 20-zeptoliter volume [ 65 ]. A plasmon-enhanced FND nano-assembly has also been introduced for imaging and biosensing in HeLa cells [ 66 ]. When subject to a proper sensing methodology, functionalized nanodiamonds allow controlled intracellular heating (photothermal therapy) and thermometry in the HeLa cell line [ 67 ].…”

DNA-Patched Nanoparticles for the Self-Assembly of Colloidal Metamaterials

“…Colloidal materials, as exemplified by metallic nanoparticles, solid-state quantum emitters, and polymeric nanoparticles, possess unique optical, magnetic, and electronic properties with a wide array of applications in biomedicine, optics, and catalytic reactions. − While tunable by manipulating the size, shape, or surface chemistry at the single nanoparticle level, their achievable functionalities are typically limited by the finite behaviors intrinsic to a given nanoparticle. − To enrich the properties of colloidal materials and extend their applicability, there is a growing demand for rational design and judicious assembly of nanoparticles bearing distinct functionalities. − This is because structurally diverse and compositionally heterogeneous nanoassemblies, also called colloidal metamaterials, exhibit many coveted properties derived from the synergistic effects of the constituent nanoparticles, which are rarely or never seen at the single nanoparticle level. ,,, In particular, small clusters of colloidal metamaterials with a low coordination number that recapitulate the structure of simple molecules permit customizing and fine-tuning of the material attributes conferred by the organization of and the specific interaction among constituent nanoparticles. − Harvesting such exquisite material attributes for potential applications, thus, necessitates establishing precise control over their structural configuration with high fidelity. − Yet, it remains profoundly challenging to fabricate molecule-like small clusters of colloidal metamaterials with desired architecture, as a lack of regioselectively encoded surface chemical heterogeneity prevents specific recognition and interactions among constituent nanoparticles, a prerequisite for programmable colloidal self-assembly. − …”

“… 12 − 16 This is because structurally diverse and compositionally heterogeneous nanoassemblies, also called colloidal metamaterials, exhibit many coveted properties derived from the synergistic effects of the constituent nanoparticles, which are rarely or never seen at the single nanoparticle level. 1 , 4 , 17 , 18 In particular, small clusters of colloidal metamaterials with a low coordination number that recapitulate the structure of simple molecules permit customizing and fine-tuning of the material attributes conferred by the organization of and the specific interaction among constituent nanoparticles. 19 − 21 Harvesting such exquisite material attributes for potential applications, thus, necessitates establishing precise control over their structural configuration with high fidelity.…”