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12 meses de embargo author can archive pre-print (ie pre-refereeing) subject to Restrictions below, author can archive post-print (ie final draft post-refereeing) A versatile method for the preparation of efficient and reusable nanocatalysts involving the painting of a commercial filter paper with a Pd@CNT (CNT=carbon nanotubes) ink was herein explored. The resulting paper-based material provided excellent results in the semihydrogenation of alkynes and alkynols and could be recycled at least five times without loss of activity or selectivity.

An ion-selective electrode for the highly sensitive and selective determination of creatinine in urine is presented. The enhanced recognition of creatininium cations is achieved through the use of a newly synthesized calix[4]pyrrole-based molecule, which is incorporated as an ionophore into a suitable polymeric membrane. The corresponding complex formation constants with creatininium, potassium and sodium are calculated in the polymeric membrane and confirms the strong interactions between the ionophore and the target. With this approach, the potentiometric sensor presents excellent analytical parameters with good selectivity against major components of biological fluids. Furthermore, the pH control as well as the suitable dilution factor demonstrate to be mandatory for the challenging detection in real sample. The analytical performance of the sensor is indeed tested by measuring creatinine in urine samples (N=50). The results obtained are validated against the standard colorimetric technique (Jaffé’s reaction), showing that the determination can be performed in an accurate way with minimal sample manipulation. Because of the physiological relevance of the determination of creatinine and the simplicity of the approach presented, this sensor has the potential to become a powerful tool in clinical settings as well as in point of care applications.

author can archive pre-print (ie pre-refereeing) author can archive post-print (ie final draft post-refereeing) Small and well defined Rh nanoparticles (

10.1016/j.aca.2014.04.022 The development of a solid-contact potentiometric sensor based on conducting rubbers using a carbon nanotubes ink is described here. Commercial rubbers are turned into conductive ones by a simple and versatile method, i.e. painting an aqueous dispersion of single-walled carbon nanotubes on the polymer surface. On this substrate, both the working ion-selective electrode and the reference electrode are built in order to form an integrated potentiometric cell. As a proof-of-principle, selective potassium electrodes are fully characterized giving comparable performances to conventional electrodes (sensitivity, selectivity, stability, linear range, limit of detection and reproducibility). As an application of the rubber-based electrodes, a bracelet was constructed to measure potassium levels in artificial sweat. Since rubbers are ubiquitous in our quotidian life, this approach offers great promise for the generation of chemical information through daily objects.

10.1039/c3lc51098k

10.1016/j.ymeth.2013.07.008 In this paper we present a new generation of potentiometric biosensors based on carbon nanotubes (transducer layer of the biosensor) and aptamers (sensing layer of the biosensor) for the ultralow and selective detection of microorganisms. We show that with these aptasensors we were able to detect a few CFU of the target bacteria almost in real-time, both in buffered and in real samples.

10.1039/c3an00313b

Angiogenesis is the physiologic formation of new vessels from existent vascular bed. Angiogenic branching is regulated by balance of angiogenic activators and angiogenic inhibitors. The most remarkable factor affecting angiogenesis is vascular endothelial growth factor which acts via receptor tyrosin kinase. Ongoing studies on angiogenesis also highlight therapeutic approaches for tumor metastasis and metabolic diseases.

Despite predictions of their widespread application in healthcare and environmental monitoring, electrochemical sensors are yet to be distributed at scale, instead remaining largely confined to R&D labs. This contrasts sharply with the situation for physical sensors, which are now ubiquitous and seamlessly embedded in the mature ecosystem provided by electronics and connectivity protocols. Although chemical sensors could be integrated into the same ecosystem, there are fundamental issues with these sensors in the three key areas of analytical performance, usability, and affordability. Nevertheless, advances are being made in each of these fields, leading to hope that the deployment of automated and user-friendly low-cost electrochemical sensors is on the horizon. Here, we present a brief survey of key challenges and advances in the development of distributed electrochemical sensors for liquid samples, geared towards applications in healthcare and wellbeing, environmental monitoring, and homeland security. As will be seen, in many cases the analytical performance of the sensor is acceptable; it is usability that is the major barrier to commercial viability at this moment. Were this to be overcome, the issue of affordability could be addressed.

A sensor for monitoring total ion activity is described, and its performance as a wearable device for monitoring the total ion levels of sweat is evaluated. The sensor works by tracking changes in the Donnan potential generated across a Nafion® membrane. This cation-exchange polymer was cast on a paper coated with carbon-ink, making the platform elegantly simple. Analytical parameters during calibration in aqueous solution include a sensitivity of 56.3±1.0 mV/dec.a(Na+) and a standard deviation between standard electrode potentials of 5.3 mV (N=5) for first time use. By integrating a paper based pseudo reference electrode, a miniature disposable electrochemical cell (the “IonSens” device) was created and demonstrated as a wearable sensor. Potentiometric measurements estimating the total ion activities were validated against conductivity measurements. Recoveries of eleven raw sweat samples were determined to be 95.2±6.6% (n=3). The perspiration conductivity profile of an athlete during exercise was monitored in real-time and visualized on a mobile phone application connected via Bluetooth®. The excellent reproducibility of the electrode without any conditioning is noteworthy and lends itself to applications including – but not limited to – the monitoring of total ion activity in sweat.

Current methods for creatinine quantification present significant drawbacks when aiming to combine accuracy, simplicity and affordability. Here, we report an unprecedented synthetic receptor, a mono-phosphonate aryl-extended calix[4]pyrrole, displaying remarkable affinity for creatinine and the creatininium cation. The receptor works by including the guests in its deep and polar aromatic cavity and establishing directional interactions in three dimensions. When incorporated into a suitable polymeric membrane, this molecule acts as an ionophore, playing the key role in a highly sensitive and selective potentiometric sensor suitable for the determination of creatinine in biological fluids such as urine or plasma in an accurate.

A versatile method for the preparation of efficient and reusable nanocatalysts involving the painting of a commercial filter paper with a Pd@CNT ink is here described. The resulting paper-based material provided excellent results in the semi-hydrogenation of alkynes and alkynols and could be recycled at least 5 times without loss of activity nor selectivity.

A new biosensor for monitoring glucose levels in beverages is presented. The measurements are performed using potentiometric detection. Working electrodes are made using platinised paper as support and a biocompatible polymeric membrane made of a mixture of polyvinyl alcohol and chitosan containing glucose oxidase as the recognition layer. The system is based on the detection of the hydrogen peroxide generated by an enzymatic reaction performed in a highly sensitive, selective and simple way. The biosensors display suitable analytical performance (sensitivity −119.6 ± 6.4 mV/dec in the 0.03–1.0 mM range with a limit of detection of 0.02 mM). Determination of glucose in commercial orange juices is presented. These results were validated against conventional standard methods, showing good accuracy and fast analytical response. The methodology presented herein does not require complex samples treatment, offering an alternative to conventional methods, particularly for determinations performed with minimal expertise and without a laboratory infrastructure.

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An ion-selective electrode for the highly sensitive and selective determination of creatinine in urine is presented. The enhanced recognition of creatininium cations is achieved through the use of a newly synthesized calix[4]pyrrole-based molecule, which is incorporated as an ionophore into a suitable polymeric membrane. The corresponding complex formation constants with creatininium, potassium and sodium are calculated in the polymeric membrane and confirms the strong interactions between the ionophore and the target. With this approach, the potentiometric sensor presents excellent analytical parameters with good selectivity against major components of biological fluids. Furthermore, the pH control as well as the suitable dilution factor demonstrate to be mandatory for the challenging detection in real sample. The analytical performance of the sensor is indeed tested by measuring creatinine in urine samples (N=50). The results obtained are validated against the standard colorimetric technique (Jaffé’s reaction), showing that the determination can be performed in an accurate way with minimal sample manipulation. Because of the physiological relevance of the determination of creatinine and the simplicity of the approach presented, this sensor has the potential to become a powerful tool in clinical settings as well as in point of care applications.

Novel membrane-free chemically modified polystyrene microspheres for the optical detection of sulphate in aqueous media are introduced. The working principle of this sensor, based on the surface mass-extraction of the target species, allows overcoming the strong hydration energy penalty, a typical problem for the detection of divalent anions. This optical sensor exhibits both, enhanced sensitivity and selectivity, which allows the accurate detection of sulphate biological samples. To illustrate these features, the determination of sulphate in urine is presented.