in-vitro-selection-aptamers-to-differentiate-infectious-from-non

In Vitro Selection of Aptamers to Differentiate Infectious from Non-Infectious Viruses

Virus infections have a major impact on society; most methods of detection have difficulties in determining whether a detected virus is infectious, ...

Universidad de Buenos Aires

A polyelectrolyte-surfactant complex, polyallylamine-dodecylsulfate system, is presented as an alternative method for the modification of membranes. Due its chemical structure, the complex, once casted on a surface, is highly stable in aqueous solutions. This allows modifying with the same method different types of membranes, exemplified here by alumina and polycarbonate. Using different strategies, the complex system can also incorporate other elements useful for catalysis, biorecognition, or separation. Two applications are presented: the incorporation of gold nanoparticles to catalyze the reduction of 4-nitrophenol using a polycarbonate membrane, and the modification of alumina with a biotin derivative for the recognition of avidin in label-free sensors.

A polyelectrolyte-surfactant complex as support layer for membrane functionalization.

The synthesis of atomic metal (gold and nickel) clusters by pulsed galvanostatic electrodeposition on nanoporous alumina is presented. The method allows the production of clusters with an average diameter of 0.7 nm for gold and 1.1 nm for nickel, while the size can be controlled through the current density applied. This strategy represents a simple and efficient method for the construction of heterogeneous catalysts and sub-nanometre electrode arrays exemplified here by the reduction of 4-nitrophenol and the electrochemical response to ferrocyanide. 

Synthesis of atomic metal clusters on nanoporous alumina.

Nanoelectrode arrays have introduced a complete new battery of devices with fascinating electrocatalytic, sensitivity, and selectivity properties. To understand and predict the electrochemical response of these arrays, a theoretical framework is needed. Cyclic voltammetry is a well-fitted experimental technique to understand the undergoing diffusion and kinetics processes. Previous works describing microelectrode arrays have exploited the interelectrode distance to simulate its behavior as the summation of individual electrodes. This approach becomes limited when the size of the electrodes decreases to the nanometer scale due to their strong radial effect with the consequent overlapping of the diffusional fields. In this work, we present a computational model able to simulate the electrochemical behavior of arrays working either as the summation of individual electrodes or being affected by the overlapping of the diffusional fields without previous considerations. Our computational model relays in dividing a regular electrode array in cells. In each of them, there is a central electrode surrounded by neighbor electrodes; these neighbor electrodes are transformed in a ring maintaining the same active electrode area than the summation of the closest neighbor electrodes. Using this axial neighbor symmetry approximation, the problem acquires a cylindrical symmetry, being applicable to any diffusion pattern. The model is validated against micro- and nanoelectrode arrays showing its ability to predict their behavior and therefore to be used as a designing tool.

Ana Sol Peinetti

INQUIMAE (CONICET),
Departamento de Química Inorgánica,
Analítica y Química Física,
Facultad de Ciencias Exactas y Naturales,
INQUIMAE (CONICET), Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales

Universidad de Buenos Aires

In Vitro Selection of Aptamers to Differentiate Infectious from Non-Infectious Viruses