Center for Nanoscience and Nanotechnology

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Jan 2025 • ACS nano

Photocatalytic Semiconductor–Metal Hybrid Nanoparticles: Single-Atom Catalyst Regime Surpasses Metal Tips

Shira Gigi, Tal Cohen, Diego Florio, Adar Levi, David Stone, Ofer Katoa, Junying Li, Jing Liu, Sergei Remennik, Franco VA Camargo, Giulio Cerullo, Anatoly I Frenkel, Uri Banin

Semiconductor–metal hybrid nanoparticles (HNPs) are promising materials for photocatalytic applications, such as water splitting for green hydrogen generation. While most studies have focused on Cd containing HNPs, the realization of actual applications will require environmentally compatible systems. Using heavy-metal free ZnSe-Au HNPs as a model, we investigate the dependence of their functionality and efficiency on the cocatalyst metal domain characteristics ranging from the single-atom catalyst (SAC) regime to metal-tipped systems. The SAC regime was achieved via the deposition of individual atomic cocatalysts on the semiconductor nanocrystals in solution. Utilizing a combination of electron microscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy, we established the presence of single Au atoms on the ZnSe nanorod surface. Upon increased Au concentration, this transitions …

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2025 • Journal of Materials Chemistry B, 2025

Self-assembled peptide-based nanofibers for cardiovascular tissue regeneration

Dhriti Shenoy, Sowmya Chivukula, Nursu Erdogan, Enrica Chiesa, Sara Pellegrino, Meital Reches, Ida Genta

Cardiovascular diseases are the leading cause of death worldwide, claiming millions of lives every year. Cardiac tissue engineering has emerged as a versatile option for repairing cardiac tissue and helping its regeneration. The use of nanomaterials, particularly nanofiber-based scaffolds combined with biomolecular cues like peptides, has significantly improved the compatibility and efficacy of the scaffolds for cardiac tissue regeneration. By utilising the self-assembly properties of peptides to create nanofiber scaffolds, we can achieve stability that closely mimics the natural components of cardiac tissue, making them perfect for cardiac tissue regeneration. In this review, we highlighted the dynamic process of self-assembly into nanofibers and the use of various self-assembled nanofibers for cardiovascular tissue regeneration, focusing on their roles in antithrombotic, angiogenic, differentiation, proliferation, and anti …

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Dec 2024 • Chemical Engineering Journal

A fluorine-free superhydrophobic coating fabricated by amino acids on soft electroadhesives

Tan Hu, Yixuan Jiang, Mohammad Taha, Adit Gupta, Qiuchun Lu, Edit Y Tshuva, Pooi See Lee, Meital Reches

Superhydrophobic surfaces are of high importance for generating self-cleaning surfaces that can also prevent corrosion, biofouling, fogging, and icing. Current superhydrophobic surfaces, often based on fluorinated compounds, pose environmental concerns, have high fabrication costs, and exhibit low stability. Herein, we designed fluorine-free amino acid-based nanoparticles (SiO2-Phe-Cbz NPs) to fabricate a superhydrophobic coating on elastomers that can be utilized in soft electroadhesive (EA) grippers. The synthesized SiO2-Phe-Cbz NPs are spherical with a diameter of ∼100 nm. Importantly, the synthesized NPs are non-toxic to mammalian cells. The SiO2-Phe-Cbz coating is achieved by spray-coating resulting in a water contact angle of ∼160° and a sliding angle of ∼1°. Notably, the SiO2-Phe-Cbz superhydrophobic coating presents high stability and self-cleaning properties. Furthermore, the coating …

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Dec 2024 • ACS nano

Collective Interactions of Quantum-Confined Excitons in Halide Perovskite Nanocrystal Superlattices

Shai Levy, Orr Be’er, Saar Shaek, Alexey Gorlach, Einav Scharf, Yonatan Ossia, Rotem Liran, Kobi Cohen, Rotem Strassberg, Ido Kaminer, Uri Banin, Yehonadav Bekenstein

Collective optical properties can emerge from an ordered ensemble of emitters due to interactions between the individual units. Superlattices of halide perovskite nanocrystals exhibit collective light emission, influenced by dipole–dipole interactions between simultaneously excited nanocrystals. This coupling changes both the emission energy and rate compared to the emission of uncoupled nanocrystals. We demonstrate how quantum confinement governs the nature of the coupling between the nanocrystals in the ensemble. The extent of confinement is modified by controlling the nanocrystal size or by compositional control over the Bohr radius. In superlattices made of weakly confined nanocrystals, the collective emission is red-shifted with a faster emission rate, showing the key characteristics of superfluorescence. In contrast, the collective emission of stronger quantum-confined nanocrystals is blue-shifted with a …

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Nov 2024 • arXiv preprint arXiv:2411.04937

Tunable transmissive metasurface based on thin-film lithium niobate

Zetian Chen, Noa Mazurski, Jacob Engelberg, Uriel Levy

Active metasurfaces hold great promise for spatial light modulation, and electro-optic tuning using lithium niobate is particularly attractive due to its high transparency and well-established thin-film platform. In this work, we present a free-space transmissive light modulator based on a seemingly un-patterned thin-film lithium niobate-on-insulator platform, integrated with a transparent conductive oxide meta-grating fabricated through a single lithography process. Guided mode resonance in the near-infrared region is induced with high mode confinement within lithium niobate layer, which directly in contact with the electrodes. A notable resonance shift of 0.38 nm is observed for the fundamental mode under +-10 V bias, while a maximum modulation amplitude of 4.6% is achieved for another higher-order mode. Incident angle is further exploited as another tuning parameter to split and sensitively shift the resonances. These results demonstrate the potential of this design for applications in compact, scalable, and tunable spatial light modulation devices.

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Nov 2024 • Journal of Colloid and Interface Science

A self-standing superhydrophobic material formed by the self-assembly of an individual amino acid

Tan Hu, Zhuo Zhang, Meital Reches

HypothesisThere is a growing interest in designing superhydrophobic materials for many applications including self-clean surfaces, separation systems, and antifouling solutions. Peptides and amino acids offer attractive building blocks for these materials since they are biocompatible and biodegradable and can self-assemble into complex ordered structures.Experiments and SimulationsWe designed a self-standing superhydrophobic material through the self-assembly of an individual functionalized aromatic amino acid, Cbz-Phe(4F). The self-assembly of Cbz-Phe(4F) was investigated by experimental and computational methods. Moreover, when drop-casted three times on a solid support, it formed a self-standing superhydrophobic material. The mechanical properties and chemical stability of this self-standing superhydrophobic material were demonstrated.FindingsThe designed Cbz-Phe(4F) self-assembled into …

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Nov 2024 • ACS Energy Letters

Size-Dependent Photocatalysis by Wurtzite InP Quantum Dots Utilizing the Red Spectral Region

David Stone, Shira Gigi, Tom Naor, Xiang Li, Uri Banin

Photocatalytic hydrogen generation offers a sustainable method for generating solar fuels. Indium phosphide (InP) nanocrystal quantum dots (QDs), with their adjustable band gaps and versatile surface properties, present an eco-friendly alternative to heavy-metal-based semiconductor NCs as photocatalysts. We report the synthesis of wurtzite InP (w-InP) QDs and their performance as photocatalysts for hydrogen generation from water by using the red part of the solar spectrum. Size-controlled w-InP QDs with absorption edges extending to 750 nm were synthesized via a cation exchange route. Stabilized in water with sulfides, these QDs demonstrated higher hydrogen generation efficiencies compared with other narrow-band-gap QDs. The overall hydrogen generation efficiency sharply decreases with the size. A mixed-size approach combining the high efficiency of small QDs with the broad absorption range of …

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Oct 2024 • ACS Photonics

Enhancing Broad Band Photoresponse of 2D Transition-Metal Dichalcogenide Materials Integrated with Hyperbolic Metamaterial Nanocavities

Sakal Singla, Christian Frydendahl, Pragya Joshi, Noa Mazurski, SRK Chaitanya Indukuri, Biswanath Chakraborty, Uriel Levy

Transition-metal dichalcogenides (TMDCs) are becoming an important material platform for constructing atomically thin optoelectronic devices, mostly due to their direct-to-indirect band gap tunability depending on their thickness and their ease of integration with various material platforms. One of the most challenging applications of TMDCs is their utilization as efficient photodetectors, mostly due to their nanoscale thickness, which limits their light absorption. To enhance the photodetection capabilities of TMDCs, one needs to adopt schemes for light–matter interaction enhancement. In this regard, the platform of hyperbolic metamaterial (HMM) nanocavities with indefinite dispersion and localized electromagnetic fields holds a great promise to enhance light–matter interactions. Motivated by the need for improving the performance of atomically thin photodetectors and considering the capabilities of HMMs, we hereby …

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Oct 2024 • Nanophotonics

Silicon rich nitride: a platform for controllable structural colors

Oren Goldberg, Noa Mazurski, Uriel Levy

High refractive index dielectric materials like silicon rich nitride (SRN) are critical for constructing advanced dielectric metasurfaces but are limited by transparency and complementary metal oxide semiconductor (CMOS) process compatibility. SRN’s refractive index can be adjusted by varying the silicon to nitride ratio, although this increases absorption, particularly in the blue spectrum. Dielectric metasurfaces, which utilize the material’s high dielectric constant and nano-resonator geometry, experience loss amplification due to resonance, affecting light reflection, light transmission, and quality factor. This study explores the impact of varying the silicon ratio on structural color applications in metasurfaces, using metrics such as gamut coverage, saturation, and reflection amplitude. We found that a higher SRN ratio enhances these metrics, making it ideal for producing vivid structural colors. Our results show that SRN …

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Oct 2024 • Chemosensors

Quantitative Chemical Sensing Using Genetically Engineered Bacterial Bioreporters

Yonatan Uziel, Yossef Kabessa, Benjamin Shemer, Etai Shpigel, Shimshon Belkin, Aharon J Agranat

We present a generic quantitative chemical sensing methodology for assessing the concentration of a target material (TM) in an aqueous solution by using bioluminescent microbial bioreporters as the core sensing elements. Such bioreporters, genetically engineered to respond to the presence of a TM in their microenvironment by emitting bioluminescence, have previously been mostly designed to report the presence or absence of the TM in the sample. We extend this methodology to also assess the TM concentration, by exploiting the dose-dependency of the TM-induced luminescence. To overcome luminescence intensity variations due to bacterial batch differences and the ambient temperature, simultaneous measurements were carried out on sample solutions containing known concentrations of the TM. A “standard ratio” parameter, defined as the ratio between the two measurements, is shown to be independent of the bacterial batch and the temperature, and hence provides the conceptual basis for a generic quantitative chemical sensing methodology. Assessment of 2,4-dinitrotoluene (DNT) concentration in solutions is demonstrated with an accuracy of 2.5% over a wide dynamic range.

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Oct 2024 • arXiv preprint arXiv:2410.07310

Field‐Induced Antiferromagnetic Correlations in a Nanopatterned Van der Waals Ferromagnet: A Potential Artificial Spin Ice

Avia Noah, Nofar Fridman, Yishay Zur, Maya Markman, Yotam Katz King, Maya Klang, Ricardo Rama-Eiroa, Harshvardhan Solanki, Michael L Reichenberg Ashby, Tamar Levin, Edwin Herrera, Martin E Huber, Snir Gazit, Elton JG Santos, Hermann Suderow, Hadar Steinberg, Oded Millo, Yonathan Anahory

Nano-patterned magnetic materials have opened new venues on the investigation of strongly correlated phenomena including artificial spin-ice systems, geometric frustration, magnetic monopoles, for technologically important applications such as reconfigurable ferromagnetism. With the advent of atomically thin two-dimensional (2D) van der Waals (vdW) magnets a pertinent question is whether such compounds could make their way into this realm where interactions can be tailored so that unconventional states of matter could be assessed. Here we show that square islands of CrGeTe3 vdW ferromagnets distributed in a grid manifest antiferromagnetic correlations, essential to enable frustration resulting in an artificial spin-ice. By using a combination of SQUID-on-tip microscopy, focused ion beam lithography, and atomistic spin dynamic simulations, we show that pristine, isolated CGT flakes as small as 150*150*60 nm3 have tunable dipole-dipole interactions, which can be precisely controlled by their lateral spacing. There is a crossover between non-interacting islands and significant inter-island anticorrelation depending how they are spatially distributed allowing the creation of complex magnetic patterns not observable at the isolated flakes. Our findings suggest that the cross-talk between the nano-patterned magnets can be explored in the generation of even more complex spin configurations where exotic interactions may be manipulated in an unprecedent way.

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Oct 2024 • Quantum Nanophotonic Materials, Devices, and Systems 2024, PC131200A, 2024

Chip scale configurations for light-vapor interactions

Uriel Levy, Arie Grosman, Noa Mazurski, Roy Maman, Ilan Sher

We hereby present our recent work related to the interaction of light with vapor and 2-D materials, enhanced by metasurfaces. Both free space and guided wave configurations will be discussed. We will show how Rubidium vapor and other species can modulate the phase and amplitude of the local field, benefiting from the strong enhancement of the light-matter interactions.

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Oct 2024 • Metamaterials, Metadevices, and Metasystems 2024, PC1310917, 2024

Dielectric metasurfaces: expanding the horizons

Uriel Levy, Roy Maman, Oren Goldberg, Jacob Engelberg, Arieh Grosman, Adi Shlezinger, Noa Mazurski

In this talk we will present our recent results related to metasurfaces. This includes new CMOS compatible platforms for structural colors, overcoming chromatic aberrations in metalenses, the fusion of atomic physics and metasurfaces, and metasurface real time control.

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Oct 2024 • Sensors

A Microbial Cocaine Bioreporter

Anne-Kathrin Grimm, Dor Rozanes, Etai Shpigel, Liat Moscovici, Shimshon Belkin

The continuous emergence of new illegal compounds, particularly psychoactive chemicals, poses significant challenges for current drug detection methods. Developing new protocols and kits for each new drug requires substantial time, effort, and dedicated manpower. Whole-cell bacterial bioreporters have been proven capable of detecting diverse hazardous compounds in both laboratory and field settings, identifying not only single compounds but also chemical families. We present the development of a microbial bioreporter for the detection of cocaine, the nervous system stimulant that is the second-most widely used illegal drug in the US. Escherichia coli was transformed with a plasmid containing a bacterial luxCDABEG bioluminescence gene cassette, activated by a cocaine-responsive signaling cascade. The engineered bioreporter is demonstrated to be a sensitive and specific first-generation detection system for cocaine, with detection thresholds of 17 ± 8 μg/L and 130 ± 50 μg/L in a buffer solution and in urine, respectively. Further improvement of the sensor’s performance was achieved by altering the nucleotide sequence of the PBen gene promoter, the construct’s sensing element, using accelerated site-directed evolution. The applicability of ready-to-use paper strips with immobilized bioreporter cells was demonstrated for cocaine detection in aqueous solutions.

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Aug 2024 • arXiv preprint arXiv:2408.02188

The Role of Superlattice Phonons in Charge Localization Across Quantum Dot Arrays

Bokang Hou, Matthew Coley-O'Rourke, Uri Banin, Michael Thoss, Eran Rabani

Semiconductor quantum dot (QD) assemblies are utilized in solar cells and light-harvesting devices because of their distinct physical and optical properties. Recent experiments have successfully synthesized QD molecules, arrays, and assemblies with precision by directly attaching QDs. These systems demonstrate high carrier mobility while preserving the optical properties of the individual QD components. However, despite advancements in fabricating these superstructures, a comprehensive understanding of the charge transfer process at the microscopic level is still lacking. Here, we theoretically investigated the electron transfer dynamics across finite 1-dimensional CdSe-CdS core-shell QD arrays, with QDs. The electronic and vibronic properties of the QD arrays were calculated using a semiempirical pseudopotential method and the electron transfer dynamics were studied using a mixed quantum-classical mapping approach. We find that as increases, the superlattice bending and the symmetric stretch modes can significantly localize electron transfer in the nonadiabatic regime, particularly when the connecting neck between the QDs is narrow, resulting in charge localization for large values of . This behavior is quite different in the adiabatic limit when the neck connecting the QDs is wide, where such modes can facilitate electron transfer, partially governed by decoherence times. The interplay between electronic and super-lattice couplings is thus crucial for designing high-mobility devices based on QD superlattices and avoiding charge localization.

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Jul 2024 • ACS Applied Materials & Interfaces

NC Meets CN: Porous Photoanodes with Polymeric Carbon Nitride/ZnSe Nanocrystal Heterojunctions for Photoelectrochemical Applications

Sanjit Mondal, Tom Naor, Michael Volokh, David Stone, Josep Albero, Adar Levi, Atzmon Vakahi, Hermenegildo García, Uri Banin, Menny Shalom

The utilization of photoelectrochemical cells (PEC) for converting solar energy into fuels (e.g., hydrogen) is a promising method for sustainable energy generation. We demonstrate a strategy to enhance the performance of PEC devices by integrating surface-functionalized zinc selenide (ZnSe) semiconductor nanocrystals (NCs) into porous polymeric carbon nitride (CN) matrices to form a uniformly distributed blend of NCs within the CN layer via electrophoretic deposition (EPD). The achieved type II heterojunction at the CN/NC interface exhibits intimate contact between the NCs and the CN backbone since it does not contain insulating binders. This configuration promotes efficient charge separation and suppresses carrier recombination. The reported CN/NC composite structure serves as a photoanode, demonstrating a photocurrent density of 160 ± 8 μA cm–2 at 1.23 V vs a reversible hydrogen electrode (RHE), 75 …

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Jul 2024 • ACS Applied Materials & Interfaces

NC Meets CN: Porous Photoanodes with Polymeric Carbon Nitride/ZnSe Nanocrystal Heterojunctions for Photoelectrochemical Applications

Sanjit Mondal, Tom Naor, Michael Volokh, David Stone, Josep Albero, Adar Levi, Atzmon Vakahi, Hermenegildo García, Uri Banin, Menny Shalom

The utilization of photoelectrochemical cells (PEC) for converting solar energy into fuels (e.g., hydrogen) is a promising method for sustainable energy generation. We demonstrate a strategy to enhance the performance of PEC devices by integrating surface-functionalized zinc selenide (ZnSe) semiconductor nanocrystals (NCs) into porous polymeric carbon nitride (CN) matrices to form a uniformly distributed blend of NCs within the CN layer via electrophoretic deposition (EPD). The achieved type II heterojunction at the CN/NC interface exhibits intimate contact between the NCs and the CN backbone since it does not contain insulating binders. This configuration promotes efficient charge separation and suppresses carrier recombination. The reported CN/NC composite structure serves as a photoanode, demonstrating a photocurrent density of 160 ± 8 μA cm–2 at 1.23 V vs a reversible hydrogen electrode (RHE), 75 …

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Jul 2024 • Nano Research

Mechanisms for electric field induced color change in coupled colloidal quantum dot molecules revealed by low temperatures single particle spectroscopy

Yossef E Panfil, Adar Levi, Somnath Koley, Einav Scharf, Yonatan Ossia, Uri Banin

Colloidal quantum dots (QDs), the building blocks of modern displays and optoelectronic devices, have reached the highest level of size and shape control, and stability during the last 30 years. However, full utilization of their potential requires integration or assembly of more than one nanocrystal as in the case of coupled quantum dots molecules (CQDM), where two core–shell QDs are fused to form two emission centers in close proximity. These CQDMs were recently shown to switch color under an applied electric field at room temperature. Here we use cryogenic single particle spectroscopy of single CQDMs under an electric field to show that various mechanisms can contribute to the spectrum change under an applied electric field at cryogenic temperatures. The first mechanism is the control of the delocalized electron wave function when the electric field is applied along the dimer axis. The electric field bends …

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Jun 2024 • Nano Research

Mechanisms for electric field induced color change in coupled colloidal quantum dot molecules revealed by low temperatures single particle spectroscopy

Yossef E Panfil, Adar Levi, Somnath Koley, Einav Scharf, Yonatan Ossia, Uri Banin

Mechanisms for Electric Field Induced Color Change in Coupled Colloidal Quantum Dot Molecules Revealed by Low Temperatures Single Particle Spectroscopy EN LOGIN REGISTER All data generated by the account on the platform will be deleted after logout. Close Save Journal Home > Just Accepted Nano Research Research Article | Just accepted | Available online: 21 June 2024 Mechanisms for Electric Field Induced Color Change in Coupled Colloidal Quantum Dot Molecules Revealed by Low Temperatures Single Particle Spectroscopy Show Author's Information Hide Author's Information Yossef E. Panfil 1 , † , Adar Levi 1 , Somnath Koley 1 , †† , Einav Scharf 1 , Yonatan Ossia 1 , Uri Banin 1 ( ) 1 Institute of Chemistry and the center for nanoscience and nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel † Present address: Quantum Engineering Laboratory, the Department of …

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Jun 2024 • Integrated Photonics Platforms III 13012, 176-178, 2024

CMOS-compatible electro-optical SRAM cavity device based on negative differential resistance

Rivka Gherabli, Roy Zektzer, Meir Grajower, Joseph Shappir, Christian Frydendahl, Uriel Levy

We experimentally demonstrate a new electro-optic SRAM element fully CMOS compatible. Inspired by the Esaki diode, presenting negative differential resistance (NDR), we designed a new type of NDR diode based on a horizontal PN junction and a region with higher acceptor concentration, P+, in silicon. We embedded the new NDR into a photonic micro-ring resonator to enable a bistable device with electrical and optical readout capabilities. Our device is remarkable for its simplicity, CMOS compatibility and its low power consumption around the nanowatt, but it’s also an important steppingstone on the way to new nonlinear electro-optic and neuromorphic computing structures.

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Jun 2024 • German-Israeli Cooperation in Water Technology Research

PFASense: A Bio-Electrochemical Detection Array for PerfluoroAlkyl Acids

Meghna KHADKA, Chetan Prakash SHARMA, Alexander SNEZHKO, Ruth REVACH, Liat MOSCOVIC, Marius DANHAUSEN, Shimshon BELKIN, Sebastian BUCHINGER, Avner RONEN, Miriam AMIRAM, Hadar BEN-YOAV

Industrial pollutants, including perfluoroalkyl and polyfluoroalkyl substances (PFASs), pose serious health and environmental risks. Time-consuming and expensive traditional detection techniques, including liquid chromatography-mass spectrometry, impede prompt field examination. PFASense attempts to address this problem by the development of cost-effective, dependable, and sustainable electrochemical techniques for continuous PFAS evaluation in contaminated aquatic environments. The proposed approach combines a pretreatment phase employing nanofiltration membranes to remove interfering impurities, chemometric arraybased analysis, as well as bacteria-and yeast-based whole cell biosensors. The sensors are examined in complex aqueous matrices, such as contaminated ground water, and mathematical models are employed for perfluorooctane sulfonic acid (PFOS) quantification. To date, we have demonstrated preliminary limits of PFOS detection in buffer of 151±53 nM and 53.1±19.0 nM, employing fluorinated and hydrophobic modified electrodes, respectively. We plan to eventually integrate the complementary PFASense technologies into a portable fluidic device for continuous PFAS monitoring.

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