Adsorption Of Specific Molecules Research Articles

A MODEL FOR SOLVENT MEDIATED INTERACTIONS BETWEEN MOLECULES AND SURFACES

This work introduces a novel coarse-grained model representing the dynamics of polar molecules that adsorb on a substrate in the presence of a solvent. The motivation of the model is to avoid the explicit representation of the solvent. Instead, the solvent-mediated interaction is indirectly represented using a fluctuating energy landscape. The dynamics, on which this model is based, are similar to the dynamics in game theory. In particular, the strategy of an agent in a game is similar to the modification of the free energy barrier between the molecule and the substrate induced by other companion molecules. The aim of this method is to show how the interplay between solvents and companion molecules can imply a modification in the adsorption energy of molecules, and how this modification can buffer the adsorption of specific molecules on surfaces. The results, and their implications in the molecular recognition of surfaces, are discussed.

Multiwell micromechanical cantilever array reader for biotechnology

We use a multiwell micromechanical cantilever sensor (MCS) device to measure surface stress changes induced by specific adsorption of molecules. A multiplexed assay format facilitates the monitoring of the bending of 16 MCSs in parallel. The 16 MCSs are grouped within four separate wells. Each well can be addressed independently by different analyte liquids. This enables functionalization of MCS separately by flowing different solutions through each well. In addition, each well contains a fixed reference mirror which allows measuring the absolute bending of MCS. In addition, the mirror can be used to follow refractive index changes upon mixing of different solutions. The effect of the flow rate on the MCS bending change was found to be dependent on the absolute bending value of MCS. Experiments and finite element simulations of solution exchange in wells were performed. Both revealed that one solution can be exchanged by another one after 200 microl volume has flown through. Using this device, the adsorption of thiolated DNA molecules and 6-mercapto-1-hexanol on gold surfaces was performed to test the nanomechanical response of MCS.

Chemical sensing in Fourier space

Chemical sensing using optical diffraction from an array of microcantilevers is demonstrated. Properly fashioned arrays of micromachined silicon-nitride cantilevers containing embedded deformable diffraction gratings are functionalized with chemically selective coatings. Adsorption of specific molecules on the cantilever leads to bending, which changes the diffraction pattern of a laser beam reflecting off the array. Quantitative chemical information can be obtained by monitoring the displacement of diffraction peaks as a function of analyte exposure.

Selectivity enhancement of amperometric gas detection cells: Linear potential sweep voltammetry (LPSV) after specific adsorption at fixed potentials

Linear potential sweep voltammetry (LPSV) applied after specific adsorption of molecules at a fixed potential is described. It can be used as a selectivity-enhancing operation mode for electrochemical gas-detection cells. To demonstrate this, we apply the method to identify CO in CO/H 2 gas mixtures with a polycrystalline Pt electrode.

Gas chromatography on the porous polymers Chromosorb-101 and Chromosorb-104 and their adsorption properties

On porous polymers Chromosorb-101 and Chromosorb-104 the retention volumes for zero sample size, the increments of free energies, heats of adsorption and entropies (relative to benzene) for forty aromatic compounds with different functional groups have been determined by chromatographic methods. the dependence of retention volumes of compounds of different classes on the number of carbon atoms in a molecule has been measured. The results indicate strong specific adsorption of molecules of group D on Chromosorb-104 with the formation of H-bonds, compared with weak specific adsorption of these molecules on Chromosorb-101. The results are compared with those obtained on Chromosorb-102.