AI news: Illuminating the Nano World: Tracking Molecule Dynamics in Nanofluidic Structures

In a groundbreaking collaboration, researchers from the University of Manchester and the École polytechnique fédérale de Lausanne (EPFL) in Switzerland have unveiled a pioneering method to monitor the dynamics of individual molecules within nanofluidic structures. This innovative approach sheds light on how molecules respond in nanoscale environments, providing insights that were previously inaccessible.

Nanofluidics: A World of Miniature Fluids

Nanofluidics is the study of fluids confined within ultra-small spaces, offering a unique window into the behavior of liquids on a nanometer scale. However, investigating the movement of individual molecules within such tiny confines has long been a scientific challenge due to the limitations of conventional microscopy techniques. This limitation has hindered real-time sensing and imaging, leaving significant gaps in our understanding of molecular properties in confined spaces.

Thin Channels for Molecular Insight

Led by Professor Radha Boya in the Department of Physics at The University of Manchester, the research team devised an ingenious method to overcome these limitations. They created nanochannels that are only one to a few atoms thin using two-dimensional materials as building blocks.

Professor Boya explained, "Seeing is believing, but it is not easy to see confinement effects at this scale. We make these extremely thin slit-like channels, and the current study shows an elegant way to visualize them by super-resolution microscopy."

The results of this study were published in the prestigious journal Nature Materials.

Boron Nitride's Illuminating Secret

The collaboration with the EPFL team brought an unexpected breakthrough. It was the unique properties of boron nitride, a two-dimensional material similar to graphene, that held the key. Boron nitride has the remarkable ability to emit light when in contact with liquids, and this property allowed researchers at EPFL's Laboratory of Nanoscale Biology (LBEN) to directly observe and track individual molecules within nanofluidic structures.

This discovery has opened doors to a deeper understanding of how ions and molecules behave in conditions that mimic biological systems. Professor Aleksandra Radenovic, head of LBEN, emphasized, "Advancements in fabrication and material science have empowered us to control fluidic and ionic transport on the nanoscale. Yet, our understanding of nanofluidic systems remained limited, as conventional light microscopy couldn't penetrate structures below the diffraction limit. Our research now shines a light on nanofluidics, offering insights into a realm that was largely uncharted until now."

Applications and Future Prospects

The newfound understanding of molecular properties within nanofluidic structures has promising applications. It enables the direct imaging of emerging nanofluidic systems, where liquids exhibit unconventional behaviors under pressure or voltage stimuli.

The core of this research lies in the fluorescence originating from single-photon emitters at the surface of hexagonal boron nitride. Doctoral student Nathan Ronceray from LBEN commented on this unexpected fluorescence activation, stating, "This fluorescence activation came unexpected as neither hexagonal boron nitride (hBN) nor the liquid exhibit visible-range fluorescence on their own. It most likely arises from molecules interacting with surface defects on the hBN crystal, but we are still not certain of the exact mechanism."

Dr. Yi You, a post-doc from The University of Manchester, engineered the nanochannels in a way that positioned confining liquids just nanometers from the hBN surface with some defects. Surface defects, which represent missing atoms in the crystalline structure, possess unique properties that enable them to emit light when they interact with certain molecules.

The researchers observed that when a defect turns off, a neighboring one lights up, indicating the movement of molecules from one site to another. This sequential process allows for the reconstruction of entire molecular trajectories.

By using a combination of microscopy techniques, the team could monitor color changes, demonstrating that these light emitters release photons one at a time, providing precise information about their immediate surroundings within approximately one nanometer. This breakthrough transforms these emitters into nanoscale probes, offering insights into the arrangement of molecules within confined nanoscale spaces.

Nathan Ronceray envisions diverse applications beyond passive sensing, suggesting, "We have primarily been watching the behavior of molecules with hBN without actively interacting with them, but we think it could be used to visualize nanoscale flows caused by pressure or electric fields. This could lead to more dynamic applications in the future for optical imaging and sensing, providing unprecedented insights into the intricate behaviors of molecules within these confined spaces."

This groundbreaking project received funding from several prestigious sources, including the European Research Council, Royal Society University Research Fellowship, Royal Society International Exchanges Award, and EPSRC New Horizons grant.

In conclusion, the collaborative research by the University of Manchester and EPFL has illuminated the hidden world of nanofluidics. By employing innovative materials and microscopy techniques, scientists have unlocked the ability to track individual molecules within nanoscale channels. This breakthrough promises far-reaching applications in fields ranging from materials science to biotechnology, offering unprecedented insights into molecular behavior at the smallest scales.