Organic Electrochemical Transistors (OECTs) are suitable for developing ultra-sensitive bioelectronic sensors. In the organic electrochemical transistors architecture, the source-drain channel is made of a conductive polymer film either cast from a formulated dispersion or electrodeposited from a monomer solution. The commercial poly(3,4-ethylenedioxidethiophene)/poly(styrene sulfonate) (PEDOT:PSS) water dispersion is the workhorse of organic bioelectronics for its high conductance, low impact and ease of processability. In this study, a hybrid organic electrochemical transistors channel fabrication strategy is presented, where electrochemical deposition of a PEDOT/X (with X indicating the counterion) is performed on a dispersion-cast PEDOT:PSS film. Six different counterions where used: X = PSS, Nafion, Hyaluronate, Dextran sulfate, Dexamethasone phosphate and tauroursodeoxycholic acid, each potentially endowing organic electrochemical transistors with additional functions such as ion exchange and pharmacological activity upon release of X. The PEDOT/X-PEDOT:PSS bilayers were characterized by means of electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and focused ion beam tomography combined with scanning electron microscopy (FIB-SEM). In addition, their respective organic electrochemical transistorss were characterized and compared to PEDOT:PSS organic electrochemical transistors. Our results show that the hybrid bilayer strategy is viable to fabricate multifunctional organic electrochemical transistorss with biologically-relevant function, thereby retaining the outstanding figures of merit of commercial PEDOT:PSS.

Poly(N-isopropylacrylamide)

10.3389/fmats.2022.1063763

Cite

Citations (10)

Gold Dimer Nanoantenna with Slanted Gap for Tunable LSPR and Improved SERS

The Journal of Physical Chemistry C (2014)

Sameh Kessentini Dominique Barchiesi Cristiano D’Andrea Andréa Toma Nicolas Guillot

We focus on improving the surface-enhanced Raman scattering (SERS) of dimer nanoantenna by tailoring the shape of the coupled nanoantennas extremities from rounded to straight or slanted ones. A numerical model based on the discrete dipole approximation method—taking into account periodicity, adhesion layer, and roughness—is first validated by comparison with localized surface plasmon resonance (LSPR) and SERS experiments on round-edged dimer nanoantennas and then used to investigate the effect of the straight or slanted gap in the dimer antenna. Simulations show that both LSPR and SERS can be tuned by changing the gap slanting angle. The SERS enhancement factor can also be improved by 2 orders of magnitude compared to the one reached using a rounded gap. Therefore, the slanting angle can be used as a new control parameter in the design of SERS substrates to guarantee stronger field confinement and higher sensitivity, especially as its feasibility is demonstrated.

Discrete dipole approximation

10.1021/jp409844y

Cite

Citations (97)

Nanoscale Fluid Mechanics

Springer eBooks (2012)

Minami Yoda Jean‐Luc Garden Olivier Bourgeois Aeraj Haque Aloke Kumar

10.1007/978-90-481-9751-4_100551

Cite

Citations (0)

Surface-Enhanced Infrared Spectroscopy Using Nanometer-Sized Gaps

ACS Nano (2014)

Christian Huck Frank Neubrech Jochen Vogt Andréa Toma David Gerbert

We report on the near-field coupling of individual gold nanoantennas arranged in tip-to-tip dimer configuration, leading to strong electromagnetic field enhancements in the infrared, which is of great interest for sensing applications such as surface-enhanced infrared spectroscopy. We quantitatively evaluated the enhancement of vibrational excitations of a 5 nm thick test layer of 4,4'-bis(N-carbazolyl)-1,1'-biphenyl as a function of different gap sizes. The dimers with the smallest gaps under investigation (∼3 nm) lead to more than 1 order of magnitude higher signal enhancement with respect to gaps of 50 nm width. The comparison of experimental data and finite-difference time-domain simulations reveals a nonperfect filling of the gaps with sizes below 10 nm, which means that morphological information on the nanoscale is obtained additionally to chemical information.

Nanometre

Biphenyl

10.1021/nn500903v

Cite

Citations (207)

Hot‐Spot Engineering in 3D Multi‐Branched Nanostructures: Ultrasensitive Substrates for Surface‐Enhanced Raman Spectroscopy

Advanced Optical Materials (2017)

Manohar Chirumamilla Anisha Chirumamilla Alexander S. Roberts Remo Proietti Zaccaria Francesco De Angelis

The detection of probe molecules at ultralow concentrations, even at the single‐molecule level, can be addressed with the breakthrough concept of plasmonic hot‐spot engineering. In view of that, the fabrication of nanostructures endowed with sub‐10 nm gaps and extremely large near‐field enhancement has gained increasing attention, becoming a key‐condition for improved sensitivity. The present work demonstrates a new perspective in ultrasensitive detection by engineering every individual plasmonic nanostructure with a giant electric field confinement and superior hot‐spot densities, thus eliminating the need for extremely narrow interparticle separations.

Surface-Enhanced Raman Spectroscopy

10.1002/adom.201600836

Cite

Citations (37)

Plasmonics and Super-Hydrophobicity: A New Class of Nano-Bio-Devices

Challenges and advances in computational chemistry and physics (2013)

Francesco Gentile Maria Laura Coluccio Andréa Toma Alessandro Alabastri Remo Proietti Zaccaria

SIGNAL (programming language)

10.1007/978-94-007-7805-4_14

Cite

Citations (2)

Steering and Encoding the Polarization of the Second Harmonic in the Visible with a Monolithic LiNbO₃ Metasurface

ACS Photonics (2021)

Luca Carletti Attilio Zilli F. Moia Andréa Toma Marco Finazzi

Nonlinear metasurfaces constitute a key asset in meta-optics, given their ability to scale down nonlinear optics to sub-micrometer thicknesses. To date, nonlinear metasurfaces have been mainly realized using narrow band gap semiconductors, with operation limited to the near-infrared range. Nonlinear meta-optics in the visible range can be realized using transparent materials with high refractive index, such as lithium niobate (LiNbO3). Yet, efficient operation in this strategic spectral window has been so far prevented by the nanofabrication challenges associated with LiNbO3, which considerably limit the aspect ratio and minimum size of the nanostructures (i.e., meta-atoms). Here we demonstrate the first monolithic nonlinear periodic metasurface based on LiNbO3 and operating in the visible range. Realized through ion beam milling, our metasurface features a second-harmonic (SH) conversion efficiency of 2.40 × 10–8 at a pump intensity as low as 0.5 GW/cm2. By tuning the pump polarization, we demonstrate efficient steering and polarization encoding into narrow SH diffraction orders, opening novel opportunities for polarization-encoded nonlinear meta-optics.

10.1021/acsphotonics.1c00026

Cite

Citations (95)

Pneumocystis jirovecii pneumonia prophylaxis in allogeneic hematopoietic cell transplant recipients: can we always follow the guidelines?

Bone Marrow Transplantation (2018)

Rabah Redjoul Christine Robin F. Foulet Mathieu Leclerc Florence Beckerich

Regimen

Atovaquone

Trimethoprim

Pneumocystis pneumonia

Sulfamethoxazole

Pre-exposure prophylaxis

10.1038/s41409-018-0391-2

Cite

Citations (16)

Bound States in the Continuum and Long-Range Coupling of Polaritons in Hexagonal Boron Nitride Nanoresonators

ACS Photonics (2024)

Harsh Gupta Giacomo Venturi Tatiana Contino Eli Janzen James H. Edgar

Bound states in the continuum (BICs) garnered significant interest for their potential to create new types of nanophotonic devices. Most prior demonstrations were based on arrays of dielectric resonators, which cannot be miniaturized beyond the diffraction limit, reducing the applicability of BICs for advanced functions. Here, we demonstrate BICs and quasi-BICs based on high-quality factor phonon-polariton resonances in isotopically pure h

Hexagonal boron nitride

Nanophotonics

10.1021/acsphotonics.4c00358

Cite

Citations (1)

3D X-Ray imaging of bone tissue from micro to nano scale and associated inverse problems

HAL (Le Centre pour la Communication Scientifique Directe) (2015)

Françoise Peyrin Andréa Toma Bruno Sixou Laurent Denis L. Wang

Imaging bone tissue from the organ to the cellular level is a major goal in bone research to understand, diagnose and predict bone fragility associated to bone disease such as osteoporosis. In this presentation, we show that X-ray CT is particularly well adapted to image bone in 3D up to the nanometer scale. After recalling the principles of 3D CT, we describe advances in bone CT imaging and the needs in associated inverse problems. Clinical X-ray CT is daily used to image skeletal tissue at the organ scale with a spatial resolution of about 0.5mm. However such systems do not permit to image bone micro-architecture made of a complex network of thin trabeculae (thickness about 150 µm). Imaging trabecular bone has been a driving application in the development of X-ray micro-Computerized Tomography (CT) ex-vivo. New High Resolution peripheral Quantitative CT (HR pQCT) systems provide images at voxel size around 100 µm, permitting the investigation of bone micro-structure in vivo [1]. Synchrotron X-ray CT, in addition to an accurate analysis of bone microarchitecture, provides quantitative information about the degree of mineralization of bone [2]. Finally, exploiting X-ray phase contrast has permit to reach 3D imaging of bone samples up to 50nm by using the magnified phase nano CT setup developed at the ESRF [3]. Basic CT reconstruction relies on the inversion of the Radon Transform, which is conventionally done using the Filtered Back Projection algorithm. Recently compressive sensing (CS) methods have raised increasing interest in CT imaging [4]. These algorithms are generally based on the minimization of a functional including a prior term promoting some form of sparsity. While many progresses have been made in the development of methods and algorithms, their practical uses in applications still requires developments. We describe current works and perspective in this field concerning bone imaging.

Bone tissue

Source

Cite

Citations (0)