Poster De Conférence Année : 2025

Dark-Field Interferometric Scattering Microscopy: A Label-Free Imaging Platform for Ultrafast Visualization of Nanoscopic Biological and Synthetic Entities

Résumé

Dark-field interferometric scattering (DF-iSCAT) microscopy represents a paradigm shift in ultrafast, label-free optical imaging, extending the capabilities of conventional iSCAT by integrating the contrast enhancement of dark-field microscopy with the sub-nanometric sensitivity of interferometric detection. Building upon the foundational principles of iSCAT—which leverages coherent interference between scattered and reference light to achieve single-molecule sensitivity —DF-iSCAT enables high-speed imaging of dynamic biological processes without the need for fluorescent labels. This distinguishes it, fundamentally from fluorescence-based methodologies, which suffer from photobleaching, cytotoxicity, and perturbation of native biological states. The combination of spatially coherent laser illumination, microsecond-scale temporal resolution, and advanced background suppression algorithms positions DF-iSCAT as a powerful tool for real-time interrogation of nanoscale biological systems.¹⁻⁴ These capabilities have facilitated the direct observation of rapid, transient molecular events, such as microtubule disassembly, with exquisite temporal and spatial resolution.² Expanding upon such seminal studies, we propose to further enhancement of DF-iSCAT sensitivity by optimizing the optical separation between scattered and excitation fields. This refinement improves contrast, minimizes coherent noise, and lowers the detection threshold to sub-2 nm scatterers, encompassing small proteins, extracellular vesicles, and engineered nanoparticles.⁶ In parallel, we aim to address current technical limitations—including speckle artifacts, interferometric instability, and sensitivity to refractive index heterogeneity—through the integration of adapted optics and thin-film metallic coatings for background suppression.⁵ Prospective extensions include hybrid imaging configurations coupling DF-iSCAT with optical tweezers or cryogenic modalities, as well as multimodal integration with stimulated Raman scattering, quantitative phase imaging, and plasmonic-enhanced scattering techniques.⁹⁻¹¹ These advances are expected to extend DF-iSCAT’s utility across heterogeneous biological environments while preserving molecular specificity and biophysical fidelity. Moreover, the intrinsic quantitative nature of the iSCAT signal enables extraction of molecular mass, conformational dynamics, and interaction kinetics with high precision, offering a non-invasive window into molecular behavior in its native context. By unlocking access to spatiotemporal regimes and biomolecular systems previously beyond reach, this methodological advancement stands to catalyze transformative breakthroughs in the life sciences, particularly in proteomics, structural biology, drug discovery, and nanomedicine. References 1. Robert et al., Nat. Commun. 2021, 12, 2921. 2. Vala et al., Small Methods 2021, 5, 2000985. 3. Cheng et al., J. Phys. D: Appl. Phys. 2021, 54, 364001. 4. Mazaheri et al., Optica 2024, 11, 1030–1038. 5. Küppers et al., Nat. Commun. 2023, 14, 1962. 6. Holanová et al., Opt. Laser Technol. 2019, 109, 323–327. 7. Radosevic et al., Nano Lett. 2023, 23, 4110–4118. 8. Sandoghdar et al., J. Microsc. 2012, 246, 223–232. 9. Maier, Plasmonics: Fundamentals and Applications, Springer, 2008. 10. Zhang et al., ACS Nano 2020, 14, 9631–9643. 11. Dastjerdi et al., Nano Lett. 2020, 20, 7485–7493.

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hal-05497384 , version 1 (06-02-2026)

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  • HAL Id : hal-05497384 , version 1

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Sreyash Sarkar, Yue Xu, Laurence W Fitzpatrick, Marek Piliarik. Dark-Field Interferometric Scattering Microscopy: A Label-Free Imaging Platform for Ultrafast Visualization of Nanoscopic Biological and Synthetic Entities. Nanophotonics and Micro/Nano Optics International Conference 2025, Oct 2025, Paris, France. ⟨hal-05497384⟩
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