Nanofluidics: Exploring New Frontiers

Abstract

In this talk, I will describe a novel single-molecule method where we engineer precise spatial and temporal control into the single-molecule experiment. We use a glass nanopore mounted on a 3D nanopositioner to spatially select molecules, deterministically tethered on a glass surface, for controlled translocations. By controlling the distance between the nanopore and the glass surface, we can actively select the region of interest on the molecule and scan it a controlled number of times and at a controlled velocity. Decreasing the velocity and averaging thousands of consecutive readings of the same molecule increases the signal-to-noise ratio (SNR) by two orders of magnitude compared to free translocations. We applied our method to various DNA constructs, achieving down to single nucleotide gap resolution. The spatial multiplexing combined with the sub-nanometer resolution could be used in conjunction with micro-array technologies to enable the screening of DNA, improve point-of-care devices, or enable high-density, addressable DNA data storage.

In the second part of the talk I will introduce two novel types of nanofluidic platforms. The geometry of the first nanofluidic platform combines the benefits of reduced sensing regions typically seen in 2D material nanopores with the asymmetric geometry of capillaries, resulting in ionic selectivity, stability, and scalability. The proposed nature-inspired growing method provides a flexible nanopore platform for various nanofluidic research applications, such as biosensing, energy science, and filtration technologies.

The second nanofluidic platform with a large entrance asymmetry is designed for in-memory processing, which can be mass-produced. Our fabrication process is scalable while the device operates at the second timescale with a conductance ratio in the range 10-60. In-operando optical microscopy unveils the origin of memory, arising from the reversible formation of liquid blisters modulating the device conductance. The combination of features of these mechano-ionic memristive switches permits assembling logic circuits composed of two interactive devices and an ohmic resistor. These results open the way to design multi-component ionic machinery, such as nanofluidic neural networks, and implementing brain-inspired ionic computations.

Om Professor Aleksandra Radenovic

Alexandra is a full professor of biological engineering at the École Polytechnique Fédérale de Lausanne (EPFL) and head of the Laboratory of Nanoscale Biology. Her lab works in the research field that can be termed single-molecule biophysics. She has received her Ph.D. in Biophysics from the University of Lausanne (Switzerland.) in 2003 and a Msc. in Physics from the University of Zagreb (Croatia) in 2000. In 2010. she received a European Research Council (ERC) Starting Grant in 2010 and SNF Backup scheme Consolidator Grant (2015). She is also the recipient of the CCMX materials challenge award in 2016 and the Advanced ERC (2020) grant. 

She develops techniques and methodologies based on optical imaging, bio-sensing and single-molecule manipulation with the aim to monitor the behavior of individual biological molecules and complexes in vitro and in live cells.