About

Dr. Zuzanna S. Siwy received her PhD in 1997 from the Silesian University of Technology, Gliwice, Poland, and completed her habilitation in 2004. She was a Fellow of the Foundation for Polish Science from 2000 to 2003 and a Fellow of the Alexander von Humboldt Foundation at the Institute for Heavy Ions Research (GSI) in Darmstadt, Germany. After conducting postdoctoral research at the University of Florida, Gainesville, in July 2005, Dr. Siwy joined the Department of Physics and Astronomy at the University of California, Irvine. Her current research interests focus on using synthetic nanopores as templates for biomimetic channels, ionic diodes, and ionic transistors. She has been recognized with several awards, including becoming a Fellow of the Alfred von Sloan Foundation in 2007, receiving the Presidential Early Career Award for Scientists and Engineers in 2009, and the Bessel Award from the Alexander von Humboldt Foundation.

Research topics

• Nanotechnology
• Chemistry
• Physical chemistry

Selected publications

• Reservoir computing with a heterogeneous distribution of ionic nanofluidic memristors

  Neuromorphic Computing and Engineering · 2026-02-11

  articleOpen access

  Abstract Nanofluidic memristive systems exhibit the nonlinear behavior and the short-time plasticity needed for reservoir computing (RC) networks. They use ions as information carriers and operate in an electrochemical environment, in resemblance to the biological synapses. Here we present simulation results of an RC model implementation using a parallel array of memristive nanopores as reservoir. Each nanopore of the array is simulated under distinct chemical conditions using an experimentally justified theoretical model. We demonstrate the potential of the proposed network by performing three different RC tasks: sine wave nonlinear transformation, waveform classification, and forecasting of the Mackey–Glass chaotic time series.

  PublisherOA PDFDOI

• Nanopores with dynamic pore opening diameter

  Faraday Discussions · 2026-01-01

  articleSenior authorCorresponding

  Solid state nanopores have emerged as model systems for understanding transport properties on the nanoscale. They serve as templates for both preparing mimics of biological channels and designing biological sensors. Unlike their biological inspirations, the majority of nanopores prepared thus far, however, have been structurally static devices such that the pore opening diameter is fixed. If we could prepare nanopores whose opening diameter fluctuated in time with controlled amplitude at known locations in the pore, we could create ionic memristors as well as achieve new transport modes. Here we present ∼10 nm diameter single nanopores drilled through a 10 nm thick gold layer positioned on top of a 30 nm thick silicon nitride film. Two types of devices were prepared; one containing single stranded DNA and the other containing hairpin DNA attached to the discrete layer of gold using thiol chemistry. When an external electric field was applied across a nanopore with single stranded DNA, the nanoconfined DNA molecules exhibited steric and electrical constraints that led to memristor-like behavior in the current-voltage curves. The degree of hysteresis was controlled by salt concentration, magnitude of voltage and pore diameter. In contrast, nanopores containing DNA hairpins conducted similar currents in forward and reverse bias in agreement with the rigidity of the hairpin molecule. The experiments are explained by Brownian dynamics simulations that reveal voltage and salt concentration induced changes in DNA extension. The degree of DNA extension was also found to be dependent on the location of the molecules along the pore axis. The nanopores presented here provide the first steps towards preparation of non-equilibrium nanopore systems.

  PublisherDOI

• Boosting the performance of bioelectrocatalytic electrodes by modulating the permeability of buckypapers

  Electrochemistry Communications · 2026-03-30

  articleOpen access

  Enzymatic fuel cells (EFCs) are bioelectrochemical devices used to convert chemical energy from organic fuels into electricity. Recently, a novel enzyme immobilization technique has been introduced through the use of microcavity electrodes sandwiching enzymes and redox mediators between two sheets of carbon nanotubes (CNTs), commonly referred to as buckypaper (BP) electrodes. This study evaluates how the choice of CNTs affects the performance of EFCs. Three types of BPs made from CNTs of different lengths (1.5–800 μm), diameters (9.5–60 nm) and defects were studied in terms of wettability, porosity, and permeation efficiency using methylene blue. BPs were then formed into a microcavity electrode architecture trapping bilirubin oxidase (BOx) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) as redox mediators. The highest catalytic activity noted for mixed CNT BP trapping BOx (I max = −1.46 mA/cm 2 at 0.41 V) highlights the importance of tailored BP design for optimizing the performance of EFCs. • Microcavity electrodes advance enzymatic fuel cell design. • Enzyme and mediator are sandwiched between two sheets of CNT buckypaper. • Physical properties of CNT govern O₂ transport, permeability, and enzyme retention. • Optimized CNT length and BP pore structure improve EFC performance and stability.

  PublisherDOI

• Self-grown mycelium in confined geometries as nanofluidic devices

  Nature Communications · 2026-05-15

  articleOpen access

  Abstract Precise control of ion and molecular transport at the nanoscale underpins next-generation nanofluidic technologies. However, current approaches such as top-down fabrication and bottom-up assembly remain constrained by cost, scalability, or limited programmability. Fungal mycelium—the largest natural ion transport network in soil—offers a living bio-derived route to nanofluidics. Here, we harness mycelium’s self-growth and hyphal anastomosis to construct nanofluidic structures that autonomously conform to confined geometries. With interconnected fibrous networks, nanoscale porosity, and negatively charged surfaces (−2.8 to −4.1 mC m −2 ), multispecies mycelium generates in situ adaptive pathways through channels, gaps, and open volumes. Specifically, a mycelium-integrated microchannel achieves a pH-gating switch ratio of up to 3.0 and a 55-fold enrichment for dilute cation detection. These results establish the principle that nanofluidic functionality can be biologically grown rather than fabricated, introducing a scalable, sustainable, and geometrically adaptable platform. By bypassing lithography and energy-intensive processing, this bio-derived strategy may enable living and self-organizing ion transport networks with potential applications in sensing, ionic computing, and energy conversion.

  PublisherOA PDFDOI

• Electrostatic Gating of Ionic Conductance Through Heterogeneous van der Waals Nanopores

  arXiv (Cornell University) · 2026-02-24

  articleOpen accessSenior author

  Nanofluidic ionic transistors typically require gate voltages above 1 V and operate only at sub millimolar ionic strengths, limiting their biocompatible applications. We demonstrate ionic transistors consisting of single sub 10 nm nanopores drilled in van der Waals (vdW) heterostructures with internal gate electrodes made of few layer graphene. These devices deliver up to 10fold current modulation at gate voltages as low as 0.3 V in 10 mM KCl, and 2fold modulation at near physiological 100 mM KCl. Baseline conductance with no gate shows surface charge dominated transport below 100 mM KCl consistent with negatively charged hBN walls and 5 nm opening of the pores. The surface charge and the electrochemical asymmetry introduced by the three electrode configuration govern the device behavior: negative gate voltage (VG) enriches ionic concentrations and enhances current, whereas positive VG induces a local depletion zone that suppresses transport. The current modulation by VG is dependent on the polarity of the transmembrane potential and leads to ion current rectification. Molecular dynamics simulations of a nanopore in a hBN graphene hBN stack reveal confinement and surface charge dependent suppression of relative permittivity of interfacial water. Continuum modeling with radially varying interfacial water permittivity reproduces the asymmetric IV characteristics and explains how the embedded gate sculpts local potential and ion concentrations. By enabling sub 0.5 V control of ionic transport at up to 100 mM salt concentrations, these devices address a key barrier in nanofluidics and open the pathway to low power ionic circuits and biosensing.

  PublisherOA PDF

• Electrostatic Gating of Ionic Conductance Through Heterogeneous van der Waals Nanopores

  Open MIND · 2026-02-24

  preprintSenior author

  Nanofluidic ionic transistors typically require gate voltages above 1 V and operate only at sub millimolar ionic strengths, limiting their biocompatible applications. We demonstrate ionic transistors consisting of single sub 10 nm nanopores drilled in van der Waals (vdW) heterostructures with internal gate electrodes made of few layer graphene. These devices deliver up to 10fold current modulation at gate voltages as low as 0.3 V in 10 mM KCl, and 2fold modulation at near physiological 100 mM KCl. Baseline conductance with no gate shows surface charge dominated transport below 100 mM KCl consistent with negatively charged hBN walls and 5 nm opening of the pores. The surface charge and the electrochemical asymmetry introduced by the three electrode configuration govern the device behavior: negative gate voltage (VG) enriches ionic concentrations and enhances current, whereas positive VG induces a local depletion zone that suppresses transport. The current modulation by VG is dependent on the polarity of the transmembrane potential and leads to ion current rectification. Molecular dynamics simulations of a nanopore in a hBN graphene hBN stack reveal confinement and surface charge dependent suppression of relative permittivity of interfacial water. Continuum modeling with radially varying interfacial water permittivity reproduces the asymmetric IV characteristics and explains how the embedded gate sculpts local potential and ion concentrations. By enabling sub 0.5 V control of ionic transport at up to 100 mM salt concentrations, these devices address a key barrier in nanofluidics and open the pathway to low power ionic circuits and biosensing.

  DOI

• Modulation of ionic current rectification in short unipolar nanopores

  Journal of Colloid and Interface Science · 2025-10-17 · 2 citations

  articleOpen access
  PublisherOA PDFDOI

• Systems nanoelectrochemistry from single entity to ensemble: general discussion

  Faraday Discussions · 2025-01-01

  article

  Kim McKelvey opened discussion of the paper by Paolo Actis: Can you expand on why you see enhanced signals for nanoparticle translocations when you have a large concentration of polyethylene glycol (PEG) present? Paolo Actis answered: We have discussed the mechanism in detail in

  PublisherDOI

• High-Dimension Ionic Memory in Oscillating Ion Current Signals

  Research Square · 2025-07-04

  preprintOpen access1st authorCorresponding
  PublisherOA PDFDOI

• Ion Transport through Differently Charged Nanoporous Membranes: From a Single Nanopore to Multinanopores

  Analytical Chemistry · 2025-08-25 · 14 citations

  articleOpen access

  Nanoporous membranes, leveraging their high-throughput characteristics, have been widely applied in fields such as molecular separation and energy conversion. Due to interpore interactions, besides the applied voltage and solution environment, the ion transport properties in porous membranes are influenced by the pore number and spacing. Here, to understand and control the transport properties of nanopore arrays, we systematically investigate the ion transport characteristics through membranes with different charge properties, pore numbers, and interpore distances. Using numerical simulations, we analyzed local ionic concentrations and electric potential in nanopore arrays containing nanopores with uniformly charged walls as well as unipolar diodes, i.e., pores containing a junction between a charged zone and a neutral zone and showed significant ion concentration polarization (ICP) for all studied cases. As the number of pores increased and the interpore spacing decreased, the enhanced interpore interactions through ICP led to a greater deviation of the total ionic current from the linear superposition of single-pore currents. Conversely, in bipolar nanopores whose walls contain a junction between positively and negatively charged zones, ICP becomes negligible, and interpore interactions are substantially reduced. Furthermore, for membranes with various charge properties, the total current through nanopore arrays presents different quantitative dependence on the pore number under varying pore spacings. Our findings clarify the mechanism of interpore interactions in modulating ion transport through porous membranes, providing critical insights for designing nanofluidic devices based on nanopore arrays, such as nanopore-array sensors.

  PublisherOA PDFDOI

Recent grants

• Nanoporous ionic circuits and ionic mimic of a neuron

  NSF · $450k · 2013–2017

• Collaborative Research: Ionic Amplifiers for Biosensing

  NSF · $295k · 2018–2023

• Nanopore Arrays with Tunable Chemistry for Mimicking Feedback Loops

  NSF · $910k · 2022–2027

• CAREER: Nanoporous Ionic Diodes and Ionic Transistors

  NSF · $588k · 2008–2014

Frequent coauthors

• Ivan Vlassiouk

  Oak Ridge National Laboratory

  59 shared

• Charles R. Martin

  University of Florida

  36 shared

• N. R. Aluru

  Walker (United States)

  32 shared

• Yinghua Qiu

  Soochow University

  31 shared

• John T. Fourkas

  University of Maryland, College Park

  31 shared

• Lane A. Baker

  Texas A&M University

  29 shared

• Stefan Howorka

  Institute of Structural and Molecular Biology

  24 shared

• Steven F. Buchsbaum

  Lawrence Livermore National Laboratory

  21 shared

Awards & honors

• Fellow of the Foundation for Polish Science (2000–2003)
• Fellow of the Alexander von Humboldt Foundation (2000–2003)
• Fellow of the Alfred von Sloan Foundation (2007)
• Presidential Early Career Award for Scientists and Engineers…
• Bessel Award from the Alexander von Humboldt Foundation (200…