Parallel mapping of optical near-field interactions by molecular motor-driven quantum dots

Abstract

In the vicinity of metallic nanostructures, absorption and emission rates of optical emitters can be modulated by several orders of magnitude. Control of such near-field light-matter interaction is essential for applications in biosensing, light harvesting and quantum communication and requires precise mapping of optical near-field interactions, for which single-emitter probes are promising candidates. However, currently available techniques are limited in terms of throughput, resolution and/or non-invasiveness. Here, we present an approach for the parallel mapping of optical near-field interactions with a resolution of <5 nm using surface-bound motor proteins to transport microtubules carrying single emitters (quantum dots). The deterministic motion of the quantum dots allows for the interpolation of their tracked positions, resulting in an increased spatial resolution and a suppression of localization artefacts. We apply this method to map the near-field distribution of nanoslits engraved into gold layers and find an excellent agreement with finite-difference time-domain simulations. Our technique can be readily applied to a variety of surfaces for scalable, nanometre-resolved and artefact-free near-field mapping using conventional wide-field microscopes.

Super-resolution imaging: when biophysics meets nanophotonics

“…With a completely different approach, using molecular motors or microfluidic chambers allows having deterministic information about the position of a single emitter in close proximity of a nanostructure [129,130]. Such approaches, that benefit from an a priori knowledge of the emitter's position, will be described in Section 4.4.…”

“…The results [130] show mean fluorophore brightness Ī and the quantum dot decay rate as function of position next to a plasmonic nanowire (photons are collected from the nanowire ends). The approach of Groß et al [129] leverages the fact that quantum dots constrained to 1D trajectories, defined by randomly deposited microtubules, can be accurately tracked. The sample in this work consisted of 1D slits in a metal film, illuminated from below and imaged from above.…”

Revealing and Attenuating the Electrostatic Properties of Tubulin and Its Polymers

“…[ 1–4 ] Microtubule mechanical properties (Young's modulus ≈1 GPa; persistence length 1–10 mm [ 5–8 ] ) and ability to generate forces of up to 5 pN due to polymerization [ 9 ] are key features that enable such roles, and have led to utilization within engineered nano‐ and microelectromechanical systems (NEMS/MEMS). In tandem with molecular motors, microtubules have been employed within high efficiency rectifiers, [ 10,11 ] biosensors, [ 12–14 ] direction‐specific sorters and transporters, [ 15–18 ] force‐meters, [ 19 ] as nanopatterning agents, [ 20–22 ] and even for parallel nanocomputing. [ 23 ] Interestingly, in addition to such mechanical roles, microtubule‐based systems can also exploit the highly negative charge (47 e − ) that tubulin dimers exhibit at physiological pH values.…”

From isolated structures to continuous networks: A categorization of cytoskeleton‐based motile engineered biological microstructures

“…The hybrid and isolated nature of these structures show promise in lab-on-a-chip devices, as electrical interfaces with cells, and for generating electromagnetic fields at the micron scale, to name a few. The size and hybrid nature of these structures are particularly advantageous for the precise mapping of optical near-field interactions between nanostructured materials and optical emitters in biosensing, light harvesting and quantum communication applications (Groß et al, 2018). Additionally, researchers will continue to use them as a foundational technology behind the single-molecule biophysical scientific enterprise.…”