Thermodynamic Studies on Amino Acid Solvation in Aqueous Urea

Effect of ionic liquids 1-octyl-3-methyl imidazolium bromide or 1-octyl-3-methyl imidazolium chloride on thermophysical properties and taste behavior of sucrose in aqueous media at different temperatures: Volumetric, compressibility and viscometric properties

The thermophysical properties and taste behavior of sucrose in aqueous ionic liquids {1-octyl-3-methyl imidazolium bromide and 1-octyl-3-methyl imidazolium chloride} solutions have been studied via volumetric, compressibility and viscometric properties at T = (288.15, 298.15, 308.15 and 318.15) K. The positive values of transfer volume and transfer partial molar isentropic compression indicated predominance of ionic-hydrophilic interactions in these systems. The calculated hydration number for sucrose demonstrated that dehydration of sucrose occurs in presence of both studied ionic liquids. Further, the effect of studied ionic liquids on the taste behaviour of sucrose has been discussed from ASV and ASIC parameters. Furthermore, interaction volume, V_int, and cavity volume, V_cav, have been computed from scaled particle theory (SPT).

Solubility of dl-serine and dl-phenylalanine in aqueous mixtures of dimethyl sulfoxide and solvation thermodynamics

Solvation thermodynamic data of dl-serine and dl-phenylalanine in aqueous mixtures of dimethylsulfoxide at 298.15 K were determined from solubility measurement.

Antigen detection via the rate of ion current rectification change of the antibody-modified glass nanopore membrane

Ion current rectification (ICR), defined as an increase in ion conduction at a given polarity and a decrease in ion conduction for the same voltage at the opposite polarity, i.e., a deviation from a linear ohmic response, occurs in conical shaped pores due to the voltage dependent solution conductivity within the aperture. The degree to which the ionic current rectifies is a function of the size and surface charge of the nanopore, with smaller and more highly charged pores exhibiting greater degrees of rectification. The ICR phenomenon has previously been exploited for biosensing applications, where the level of ICR for a nanopore functionalized with an analyte-specific binding molecule (e.g., an antibody, biotin, etc.) changes upon binding its target analyte (e.g., an antigen, streptavidin, etc.) due to a resulting change in the size and/or charge of the aperture. While this type of detection measurement is typically qualitative, for the first time, we demonstrate that the rate at which the nanopore ICR response changes is dependent on the concentration of the target analyte introduced. Utilizing a glass nanopore membrane (GNM) internally coated with a monoclonal antibody specific to the cleaved form of synaptosomal-associated protein 25 (cSNAP-25), creating the antibody-modified glass nanopore membrane (AMGNM), we demonstrate a correlation between the rate of ICR change and the concentration of introduced cSNAP-25, over a range of 500 nM-100 μM. The methodology presented here significantly expands the applications of nanopore ICR biosensing measurements and demonstrates that these measurements can be quantitative in nature.