Search

Multiphase aqueous-organic systems where a bicontinuous phase is in equilibrium with an excess organic and aqueous phase find various applications in industry. These systems─also known as Winsor III─are complex not only for the different phases that develop therein but also because they are multicomponent systems. In this work, we explore for the first time the use of a benchtop low-field single-sided NMR to determine the species distribution in Winsor III systems. The proposed methodology provides information at macroscopic and microscopic levels. In particular, we show the use of single-sided NMR to determine the phases' dimensions and the species distribution in a polymer-based bicontinuous system. The phases' dimensions and limits can be resolved with micrometric precision and are indicative of the bicontinuous phase stability. The species distribution is determined by means of spatially resolved NMR relaxation and diffusion experiments. It was observed that the salinity of the aqueous phase also impacts the species distribution in the bicontinuous system. Experiments show that the additive and the polymer are mainly located in the bicontinuous phase. As the salinity of the aqueous phase increases, the amount of organic components in the bicontinuous phase decreases as a consequence of the species distribution in the system. This influences the total amount of recovered organic liquid from the organic phase. The information is obtained in a relatively fast experiment and is relevant to the system's possible applications, such as enhanced oil recovery (EOR). This methodology is not only circumscribed to its application in EOR but can also be applied to the study of any emulsion or microemulsion systems without sample size or geometry constraints.

The interaction between polyamines and phosphate species is found in a wide range of biological and abiotic systems, yielding crucial consequences that range from the formation of supramolecular colloids to structure determination. In this work, the occurrence of phosphate-amino interactions is evidenced from changes in the electronic response of graphene field effect transistors (gFETs). First, the surface of the transistors is modified with poly(allylamine), and the effect of phosphate binding on the transfer characteristics is interpreted in terms of its impact on the surface charge density. The electronic response of the polyamine-functionalized gFETs is shown to be sensitive to the presence of different phosphate anions, such as orthophosphate, adenosine triphosphate, and tripolyphosphate, and a simple binding model is developed to explain the dependence of the shift of the Dirac point potential on the phosphate species concentration. Afterward, the impact of phosphate-amino interactions on the immobilization of enzymes to polyamine-modified graphene surfaces is investigated, and a decrease in the amount of anchored enzyme as the phosphate concentration increases is found. Finally, multilayer polyamine-urease biosensors are fabricated while increasing the phosphate concentration in the enzyme solution, and the sensing properties of the gFETs toward urea are evaluated. It is found that the presence of simple phosphate anions alters the nanoarchitecture of the polyelectrolyte-urease assemblies, with direct implications on urea sensing.

We hereby report on the thermodynamic and kinetic aspects of ZIF-8 MOF synthesis when performed using methanolic solutions of precursors and 3-mercaptopropionic acid (MPA) acting as a chemical modifying agent. MPA is of great interest as it allows us to gain control over the surface chemistry, shape, and size of colloidal porous nanounits formed. In particular, small and wide-angle X-ray scattering (SAXS/WAXS), and electron microscopy were employed for determination of suitable MPA : MeImH modification molar ratios for two different approaches: post-synthesis modification (PSM) and coordination modulation (CM). Using the CM approach, in situ time-resolved SAXS/WAXS experiments and dynamic light scattering (DLS) experiments were carried out for a detailed characterization of the MPA influence on the early stages of nucleation and growth processes. Complementary X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption experiments showed that MPA remains mainly surface confined and adds mesoporosity to the synthesized MOF, thus it can be used for positioning thiol moieties without compromising structural integrity. Moreover, isothermal titration calorimetry (ITC) experiments carried out using the PSM strategy allowed us to determine an enthalpy value of similar to 7 kJ mol(-1) associated with the coordination between Zn2+ and MPA for the first time to our knowledge.

We introduce a new approach for glucose oxidase (GOx) immobilization on graphene field-effect transistors (gFETs) to fabricate highly sensitive glucose sensors. The strategy relies on the electropolymerization of a layer of the copolymer poly(3-amino-benzylamine-co-aniline) (PABA) on graphene-based transistors. The synthesized polymer film provides the suitable electrostatic charge and non-denaturing environment for enzyme immobilization without the need of any chemical primer. Then, the local pH changes triggered by the enzyme-catalyzed oxidation produce a shift in the Dirac potential of the gFETs to more negative values, which is evidenced by the differences in the graphene channel conductivity and constitutes the signal transduction mechanism of the sensing devices. The assembled biosensors revealed a low LOD of 4.1 μM and were capable of detecting glucose in the range from 10 to 1000 μM in a flow configuration. Moreover, they showed sensitivity of −24.9 μA per decade of glucose concentration and a fast response time, with an average value of 190 seconds, while allowing the operation at small gate-source and drain-source voltages. Finally, the biosensors were able to successfully monitor the analyte in urine samples, showing their potential towards the fabrication of point-of-care glucose testing devices.

In this work, we present the ultra-sensitive detection of acetylcholine (Ach) using enzymatic nanofluidic biosensors in which the ionic signal is generated via local chemical amplification of enzymatic processes.

This Dataset contains the raw data from the following publication: ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Interface Engineering of “Clickable” Organic Electrochemical Transistors toward Biosensing Devices Gonzalo E. Fenoy1,2, Roger Hasler1, Christoph Lorenz3, Jacopo Movilli4, Waldemar A. Marmisollé2, Omar Azzaroni2,5, Jurriaan Huskens4, Peter Bäuerle3, and Wolfgang Knoll1,6 1 AIT Austrian Institute of Technology GmbH, 3430 Tulln an der Donau, Austria 2 Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP) CONICET, 1900 La Plata, Argentina 3 Institute for Organic Chemistry II and Advanced Materials, University of Ulm, 89081 Ulm, Germany 4 Department of Molecules & Materials, MESA+ Institute, Faculty of Science and Technology, University of Twente, AE 7500 Enschede, The Netherlands 5 CEST-UNLP Partner Lab for Bioelectronics (INIFTA), 1900 La Plata, Argentina 6 Danube Private University, 3500 Krems, Austria ACS Appl. Mater. Interfaces https://doi.org/10.1021/acsami.2c21493 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ When using this data in any form please refer to the above-mentioned publication.