Publications by authors named "Esteban Piccinini"

11 Publications

  • Page 1 of 1

Mass and charge transport in highly mesostructured polyelectrolyte/electroactive-surfactant multilayer films.

J Colloid Interface Sci 2021 Jan 24;581(Pt B):595-607. Epub 2020 Jul 24.

INQUIMAE, Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires - CONICET, Ciudad Universitaria, Pabellón 2 C1428EHA, Buenos Aires, Argentina. Electronic address:

Hypothesis: Dimensionally stable electroactive films displaying spatially addressed redox sites is still a challenging goal due to gel-like structure. Polyelectrolyte and surfactants can yield highly mesostructured films using simple buildup strategies as layer-by-layer. The use of redox modified surfactants is expected to introduce order and an electroactive response in thin films.

Experiments: The assembly of polyacrylic acid and different combinations of redox-modified and unmodified hexadecyltrimethylammonium bromide yields highly structured and electroactive thin films. The growth, viscoelastic properties, mass, and electron transport of these films were studied by combining electrochemical and quartz crystal balance with dissipation experiments.

Findings: Our results show that the films are highly rigid and poorly hydrated. The mass and charge transport reveal that the ingress (egress) of the counter ions during the electrochemical oxidation (reduction) is accompanied with a small amount of water, which is close to their hydration sphere. Thus, the generated mesostructured films present an efficient charge transport with negligible changes in their structures during the electron transfer process. The control over the meso-organization and its stability represents a promising tool in the construction of devices where the vectorial transfer of electrons, or ions, is required.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jcis.2020.07.060DOI Listing
January 2021

Mesostructured Electroactive Thin Films Through Layer-by-Layer Assembly of Redox Surfactants and Polyelectrolytes.

Chempluschem 2020 08 20;85(8):1616-1622. Epub 2020 May 20.

Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), CONICET, Diagonal 113 y 64, 1900, La Plata, Argentina.

Electroactive thin films are an important element in the devices devoted to energy conversion, actuators, and molecular electronics, among others. Their build-up by the layer-by-layer technique is an attractive choice since a fine control over the thickness and composition can be achieved. However, most of the assemblies described in the literature show a lack of internal order, and their thicknesses change upon oxidation-state alterations. In this work, we describe the formation of layer-by-layer assemblies of redox surfactants and polyelectrolytes that leads to the construction of mesoscale organized electroactive films. In contrast to thin films prepared with traditional redox polymers, here, the redox surfactant does not only allow the control of the film meso-organization (from 2D hexagonal to circular hexagonal phases) but it also allows the control of the number and position of the redox centers. Finally, these films show high stability and a negligible structural deformation under redox-state changes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cplu.202000358DOI Listing
August 2020

PEDOT-polyamine composite films for bioelectrochemical platforms - flexible and easy to derivatize.

Mater Sci Eng C Mater Biol Appl 2020 Apr 31;109:110575. Epub 2019 Dec 31.

Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CONICET, CC 16 Suc. 4, La Plata B1904DPI, Argentina; Austrian Institute of Technology - Donau-City-Strasse 1, 1220 Vienna, Austria; CEST-UNLP Partner Lab for Bioelectronics, Diagonal 64 y 113, La Plata 1900, Argentina. Electronic address:

We report a straightforward route for the preparation of flexible, electrochemically stable and easily functionalizable poly(3,4-ethylenedioxythiophene) (PEDOT) composite films deposited on PET foils as biosensing platforms. For this purpose, poly(allylamine) hydrochloride (PAH) was blended with PEDOT to provide amine-bearing sites for further biofunctionalization as well as to improve the mechanical properties of the films. The conducting PEDOT-PAH composite films were characterized by cyclic voltammetry, UV-vis and Raman spectroscopies. An exhaustive stability study was carried out from the mechanical, morphological and electrochemical viewpoint. Subsequent sugar functionalization of the available amine groups from PAH allowed for the specific recognition of lectins and the subsequent self-assembly of glycoenzymes (glucose oxidase and horseradish peroxidase) concomitant with the prevention of non-specific protein fouling. The platforms presented good bioelectrochemical performance (glucose oxidation and hydrogen peroxide reduction) in the presence of redox mediators. The developed composite films constitute a promising option for the construction of all-polymer biosensing platforms with great potential owing to their flexibility, high transmittance, electrochemical stability and the possibility of glycosylation, which provides a simple route for specific biofunctionalization as well as an effective antifouling strategy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.msec.2019.110575DOI Listing
April 2020

The effect of ionic strength and phosphate ions on the construction of redox polyelectrolyte-enzyme self-assemblies.

Phys Chem Chem Phys 2019 Oct;21(41):22947-22954

INQUIMAE (CONICET), Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina.

Layer by layer assembly of polyelectrolytes with proteins is a convenient tool for the development of functional biomaterials. Most of the studies presented in the literature are based on the electrostatic interaction between components of opposite charges, limiting the assembly possibilities. However, this process can be tuned by modifying the environment where the main constituents are dissolved. In this work, the electron transfer behavior between an electroactive polyelectrolyte (polyallylamine derivatized with an osmium complex) and a redox enzyme (glucose oxidase) is studied by assembling them in the presence of phosphate ions at different ionic strengths. Our results show that the environment from which the assembly is constructed has a significant effect on the electrochemical response. Notably, the polyelectrolyte dissolved in the presence of phosphate at high ionic strength presents a globular structure which is preserved after adsorption with substantial effects on the buildup of the multilayer system, improving the electron transfer process through the film.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9cp04037dDOI Listing
October 2019

Lectin-Recognizable MOF Glyconanoparticles: Supramolecular Glycosylation of ZIF-8 Nanocrystals by Sugar-Based Surfactants.

ACS Omega 2019 Jan 10;4(1):842-848. Epub 2019 Jan 10.

Dto. de Química, Fac. de Cs. Exactas, Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Universidad Nacional de La Plata, CONICET, Calle 64 y Diag. 113, 1900 La Plata, Argentina.

A strategy toward the integration of highly functional microporous materials, such as metal-organic frameworks (MOFs), in composites via biochemical recognition interactions is presented. Postsynthetic modification of zeolitic-imidazolate framework-8 MOF nanocrystals with a maltose-exposing biocompatible surfactant (the so-called "Glyco-MOFs") was performed to confer affinity toward lectin protein concanavalin A. The addition of small amounts of concanavalin A to the colloidal Glyco-MOF dispersion triggers the aggregation of these units into self-limited size supramolecular architectures directed by specific sugar-lectin binding interactions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsomega.8b03092DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6648402PMC
January 2019

Reversible Switching of the Dirac Point in Graphene Field-Effect Transistors Functionalized with Responsive Polymer Brushes.

Langmuir 2019 Jun 4;35(24):8038-8044. Epub 2019 Jun 4.

Departamento de Química, Facultad de Ciencias Exactas , Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Universidad Nacional de La Plata (UNLP), CONICET , Suc. 4-C.C.16, 1900 La Plata , Argentina.

The reversible control of the graphene Dirac point using external chemical stimuli is of major interest in the development of advanced electronic devices such as sensors and smart logic gates. Here, we report the coupling of chemoresponsive polymer brushes to reduced graphene oxide (rGO)-based field-effect transistors to modulate the graphene Dirac point in the presence of specific divalent cations. Poly[2-(methacryloyloxy)ethyl] phosphate (PMEP) brushes were grown on the transistor channel by atom transfer radical polymerization initiated from amine-pyrene linkers noncovalently attached to rGO surfaces. Our results show an increase in the Dirac point voltage due to electrostatic gating effects upon the specific binding of Ca and Mg to the PMEP brushes. We demonstrate that the electrostatic gating is reversibly controlled by the charge density of the polymer brushes, which depends on the divalent cation concentration. Moreover, a theoretical formalism based on the Grahame equation and a Langmuir-type binding isotherm is presented to obtain the PMEP-cation association constant from the experimental data.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.langmuir.9b00910DOI Listing
June 2019

Enzyme Multilayers on Graphene-Based FETs for Biosensing Applications.

Methods Enzymol 2018 20;609:23-46. Epub 2018 Aug 20.

INIFTA Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)-Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata-CONICET, La Plata, Argentina. Electronic address:

Electrochemical sensors represent a powerful tool for real-time measurement of a variety of analytes of much significance to different areas, ranging from clinical diagnostics to food technology. Point-of-care devices which can be used at patient bedside or for online monitoring of critical parameters are of great importance in clinical daily routine. In this work, portable, low-cost electrochemical sensors for a fast and reliable detection of the clinically relevant analyte urea have been developed. The intrinsic pH sensitivity of reduced graphene oxide (rGO)-based field-effect transistors (FETs) was exploited to monitor the enzymatic hydrolysis of urea. The functionalization of the sensor platform using the layer-by-layer technique is especially advantageous for the immobilization of the biorecognition element provided that this approach preserves the enzyme integrity as well as the rGO surface. The great selectivity of the enzyme (urease) combined with the high sensitivity of rGO-based FETs result in the construction of urea biosensors with a limit of detection (LOD) of 1μM and a linear range up to 1mM. Quantification of Cu with a LOD down to 10nM was performed by taking advantage of the specific inhibition of urease in the presence of heavy metals. These versatile biosensors offer great possibilities for further development of highly sensitive enzyme-based FETs for real-time, label-free detection of a wide variety of clinically relevant analytes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/bs.mie.2018.06.001DOI Listing
June 2019

Cascading reaction of arginase and urease on a graphene-based FET for ultrasensitive, real-time detection of arginine.

Biosens Bioelectron 2018 Sep 16;115:104-110. Epub 2018 May 16.

AIT Austrian Institute of Technology GmbH, Biosensor Technologies, Muthgasse 11, 1190 Vienna, Austria.

Herein, a biosensor based on a reduced graphene oxide field effect transistor (rGO-FET) functionalized with the cascading enzymes arginase and urease was developed for the detection of L-arginine. Arginase and urease were immobilized on the rGO-FET sensing surface via electrostatic layer-by-layer assembly using polyethylenimine (PEI) as cationic building block. The signal transduction mechanism is based on the ability of the cascading enzymes to selectively perform chemical transformations and prompt local pH changes, that are sensitively detected by the rGO-FET. In the presence of L-arginine, the transistors modified with (PEI/urease(arginase)) multilayers showed a shift in the Dirac point due to the change in the local pH close to the graphene surface, produced by the catalyzed urea hydrolysis. The transistors were able to monitor L-arginine in the 10-1000 μM linear range with a LOD of 10 μM, displaying a fast response and a good long-term stability. The sensor showed stereospecificity and high selectivity in the presence of non-target amino acids. Taking into account the label-free, real-time measurement capabilities and the easily quantifiable, electronic output signal, this biosensor offers advantages over state-of-the-art L-arginine detection methods.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bios.2018.05.027DOI Listing
September 2018

Surfactants as mesogenic agents in layer-by-layer assembled polyelectrolyte/surfactant multilayers: nanoarchitectured "soft" thin films displaying a tailored mesostructure.

Phys Chem Chem Phys 2018 Apr;20(14):9298-9308

Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA) - Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata - CONICET, Suc. 4, CC 16, La Plata, Argentina.

Interfacial supramolecular architectures displaying mesoscale organized components are of fundamental importance for developing materials with novel or optimized properties. Nevertheless, engineering the multilayer assembly of different building blocks onto a surface and exerting control over the internal mesostructure of the resulting film is still a challenging task in materials science. In the present work we demonstrate that the integration of surfactants (as mesogenic agents) into layer-by-layer (LbL) assembled polyelectrolyte multilayers offers a straightforward approach to control the internal film organization at the mesoscale level. The mesostructure of films constituted of hexadecyltrimethylammonium bromide, CTAB, and polyacrylic acid, PAA (of different molecular weights), was characterized as a function of the number of assembled layers. Structural characterization of the multilayered films by grazing-incidence small-angle X-ray scattering (GISAXS), showed the formation of mesostructured composite polyelectrolyte assemblies. Interestingly, the (PAA/CTA)n assemblies prepared with low PAA molecular weight presented different mesostructural regimes which were dependent on the number of assembled layers: a lamellar mesophase for the first bilayers, and a hexagonal circular mesophase for n ≥ 7. This interesting observation was explained in terms of the strong interaction between the substrate and the first layers leading to a particular mesophase. As the film increases its thickness, the prevalence of this strong interaction decreases and the supramolecular architecture exhibits a "bulk" mesophase. Finally, we demonstrated that the molecular weight of the polyelectrolyte has a considerable impact on the meso-organization for the (PAA/CTA)n assemblies. We consider that these studies open a path to new rational methodologies to construct "nanoarchitectured" polyelectrolyte multilayers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/C7CP08203GDOI Listing
April 2018

Enzyme-polyelectrolyte multilayer assemblies on reduced graphene oxide field-effect transistors for biosensing applications.

Biosens Bioelectron 2017 Jun 21;92:661-667. Epub 2016 Oct 21.

AIT Austrian Institute of Technology, Donau City Straße 1, 1220 Vienna, Austria.

We present the construction of layer-by-layer (LbL) assemblies of polyethylenimine and urease onto reduced-graphene-oxide based field-effect transistors (rGO FETs) for the detection of urea. This versatile biosensor platform simultaneously exploits the pH dependency of liquid-gated graphene-based transistors and the change in the local pH produced by the catalyzed hydrolysis of urea. The use of an interdigitated microchannel resulted in transistors displaying low noise, high pH sensitivity (20.3µA/pH) and transconductance values up to 800 µS. The modification of rGO FETs with a weak polyelectrolyte improved the pH response because of its transducing properties by electrostatic gating effects. In the presence of urea, the urease-modified rGO FETs showed a shift in the Dirac point due to the change in the local pH close to the graphene surface. Markedly, these devices operated at very low voltages (less than 500mV) and were able to monitor urea in the range of 1-1000µm, with a limit of detection (LOD) down to 1µm, fast response and good long-term stability. The urea-response of the transistors was enhanced by increasing the number of bilayers due to the increment of the enzyme surface coverage onto the channel. Moreover, quantification of the heavy metal Cu(with a LOD down to 10nM) was performed in aqueous solution by taking advantage of the urease specific inhibition.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bios.2016.10.035DOI Listing
June 2017

Recognition-driven assembly of self-limiting supramolecular protein nanoparticles displaying enzymatic activity.

Chem Commun (Camb) 2015 Oct 21;51(79):14754-7. Epub 2015 Aug 21.

Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA) - Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata - CONICET, Suc. 4, CC 16, 1900 La Plata, Argentina.

We report the recognition-driven assembly of self-limiting protein nanoparticles displaying enzymatic activity. Solution self-assembly of concanavalin A lectin and glycoenzyme glucose oxidase leads to the spontaneous formation of biocolloids with well-defined dimensions, narrow size distribution and remarkable stability. These biocolloids successfully recognize a glycosylated modified electrode retaining the enzyme activity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c5cc05837fDOI Listing
October 2015
-->