Dioscuri Centre of Single-Molecule Optics

Summary

Life's most vital processes take place on the nanometer scale, a billion times smaller than the size of a human body, where molecules orchestrate its complex functions. Yet, current microscopy tools face limitations in peering into this realm, which leaves us with a myriad of unanswered questions related to the fundamental understanding of molecular processes pervading life.

Text

The Dioscuri Centre for Single-Molecule Optics (DC) will open in summer 2024 and focus on developing a unique life-science toolbox based on the principles of nanooptics and nanofluidics.

This innovation will allow us to dive into a biological nano-universe and study it in ways that were not possible until today – in its natural state, in real time, and at the level of single molecules. The research will provide a rich pool of information that is currently lacking, catalyze new strategies for early diagnosis and therapeutic intervention, as well as inspire the invention of new biotechnologies mimicking nature.

Imaging of a single biomolecule in its natural state has long presented a critical challenge. The light scattering efficiency of a biomolecule is very small, and the fast Brownian motion only permits the accumulation of the scattered light for an extremely short time which the biomolecule spends in a diffraction-limited spot. These combined factors prevent direct detection of the biomolecule. To bypass these limitations, a novel optical method -Nanofluidic Scattering Microscopy (NSM) [1] – has been recently introduced. Its unique underlying principle enabled the imaging of individual biomolecules in free motion without any label. It operates in physiologically relevant conditions, in real time, without the need for immobilisation onto a surface. Moreover, this method can provide continuous measurement of weight, (hydrodynamic) size, and conformation of every single molecule imaged. Monitoring of individual biomolecules diffusing in solution represents a yet unexplored opportunity for studies of molecular transport, interactions between individual biomolecules, or analysis of complex biofluids. Further development of NSM and its applications in bioanalysis will be the core of the DC’s research programme.

The principle of NSM. (A) The experimental configuration where visible light is irradiated onto a nanochannel with a biomolecule inside, and where the light scattered from the system is collected in the dark-field configuration. (B) Selection of NSM images containing a freely moving single protein (thyroglobulin). The dark spot indicates the position of the biomolecule. The trajectory is depicted between the images. (C) Kymograph of a freely moving single protein – time-sequence of NSM images, where each vertical line corresponds to the image averaged across the short axis of the nanochannel. Adapted from [1].

 

[1] Špačková B, Klein Moberg H, Fritzsche J, et al. Label-free nanofluidic scattering microscopy of size and mass of single diffusing molecules and nanoparticles. Nat Methods. 2022;19(6):751-758. doi:10.1038/s41592-022-01491-6