Preventing the impact of solute adsorption in Taylor dispersion analysis: Application to protein and lipid nanoparticle analysis.

Taylor Dispersion Analysis (TDA) allows diffusion coefficient (D) or hydrodynamic radius (R) determination on a wide range of size between angstroms and about 300 nm. However, solute adsorption phenomena can affect the repeatability and reproducibility of TDA. Several numerical studies addressed the theoretical impact of solute adsorption in TDA, but very few experimental studies focus on this topic and no experimental methodologies were proposed so far to reduce the impact of adsorption in TDA.

Critical parameters for highly efficient and reproducible polyelectrolyte multilayer coatings for protein separation by capillary electrophoresis.

Since the introduction of polyelectrolyte multilayers to protein separation in capillary electrophoresis (CE), some progress has been made to improve separation efficiency by varying different parameters, such as buffer ionic strength and pH, polyelectrolyte nature and number of deposited layers. However, CE is often overlooked as it lacks robustness compared to other separation techniques. In this work, critical parameters for the construction of efficient and reproducible Successive multiple ionic-polymer layers (SMIL) coatings were investigated, focusing on experimental conditions, such as vial preparation and sample conservation which were shown to have a significant impact on separation performances.

Unraveling the Speciation of β-Amyloid Peptides during the Aggregation Process by Taylor Dispersion Analysis.

Aggregation mechanisms of amyloid β peptides depend on multiple intrinsic and extrinsic physicochemical factors (e.g., peptide chain length, truncation, peptide concentration, pH, ionic strength, temperature, metal concentration, etc.

Taylor Dispersion Analysis of Polysaccharides Using Backscattering Interferometry.

Taylor dispersion analysis (TDA) allows the determination of the molecular diffusion coefficient (D) or the hydrodynamic radius (R) of a solute from the peak broadening of a plug of solute in a laminar Poiseuille flow. The main limitation plaguing the broader applicability of TDA is the lack of a sensitive detection modality. UV absorption is typically used with TDA but is only suitable for UV-absorbing or derivatized compounds.

Monitoring Biopolymer Degradation by Taylor Dispersion Analysis.

This work aims at demonstrating the interest of modern Taylor dispersion analysis (TDA), performed in narrow internal diameter capillary, for monitoring biopolymer degradations. Hydrolytic and enzymatic degradations of dendrigraft poly-l-lysine taken as model compounds have been performed and monitored by TDA at different degradation times. Different approaches for the data processing of the taylorgrams are compared, including simple integration of the taylorgram, curve fitting with a finite number of Gaussian peaks, cumulant-like method and Constrained Regularized Linear Inversion approach.

Measuring arbitrary diffusion coefficient distributions of nano-objects by taylor dispersion analysis.

Taylor dispersion analysis is an absolute and straightforward characterization method that allows determining the diffusion coefficient, or equivalently the hydrodynamic radius, from angstroms to submicron size range. In this work, we investigated the use of the Constrained Regularized Linear Inversion approach as a new data processing method to extract the probability density functions of the diffusion coefficient (or hydrodynamic radius) from experimental taylorgrams. This new approach can be applied to arbitrary polydisperse samples and gives access to the whole diffusion coefficient distributions, thereby significantly enhancing the potentiality of Taylor dispersion analysis.

Polydispersity analysis of Taylor dispersion data: the cumulant method.

Taylor dispersion analysis is an increasingly popular characterization method that measures the diffusion coefficient, and hence the hydrodynamic radius, of (bio)polymers, nanoparticles, or even small molecules. In this work, we describe an extension to current data analysis schemes that allows size polydispersity to be quantified for an arbitrary sample, thereby significantly enhancing the potentiality of Taylor dispersion analysis. The method is based on a cumulant development similar to that used for the analysis of dynamic light scattering data.

On the optimization of operating conditions for Taylor dispersion analysis of mixtures.

In this work, we investigate the possibility of optimizing the operating conditions, namely mobilizing pressure, capillary length and capillary radius, for performing Taylor dispersion analysis on solutes having hydrodynamic diameter, 2Rh, between 1 and 100 nm. Optimizing Taylor dispersion analysis means finding the set of operating conditions that verify the conditions of validity of this method, and finding the most appropriate conditions that may enhance or maximize the separation performances. Our conclusion is that the performances of Taylor dispersion analysis are independent of the operating conditions, as far as the conditions of validity of the method are verified.

Determination of individual diffusion coefficients in evolving binary mixtures by taylor dispersion analysis: application to the monitoring of polymer reaction.

This study demonstrates that it is possible to get valuable information on the individual populations of a binary mixture from the signal obtained by Taylor dispersion analysis (TDA). In the case of mixtures composed of two populations of different sizes (such as a monomer/polymer mixture), the information available from TDA is not restricted to an average diffusion coefficient or an average hydrodynamic radius calculated on the entire binary mixture. In this work, TDA was used to monitor a polymerization reaction.

Taylor dispersion analysis of mixtures.

Taylor dispersion analysis (TDA) is a fast and simple method for determining hydrodynamic radii. In the case of sample mixtures, TDA, as the other nonseparative methods, leads to an average diffusion coefficient on the different molecules constituting the mixture. We set in this work the equations giving, on a consistent basis, the average values obtained by TDA with detectors with linear response functions.

Amino acid N-carboxyanhydrides: activated peptide monomers behaving as phosphate-activating agents in aqueous solution.

The hydrolysis of valine N-carboxyanhydride (NCA) in aqueous phosphate buffers was shown to proceed through nucleophilic catalysis via an aminoacyl phosphate intermediate that displays phosphorylating capabilities through a potentially prebiotic process that simulates modern biochemical metabolic pathways.

Dynamic co-evolution of peptides and chemical energetics, a gateway to the emergence of homochirality and the catalytic activity of peptides.

We propose a scenario for the dynamic co-evolution of peptides and energy on the primitive Earth. From a multi component system consisting of hydrogen cyanide, several carbonyl compounds, ammonia, alkyl amine, carbonic anhydride, borate and isocyanic acid, we show that the reversibility of this system leads to several intermediate nitriles, that irreversibly evolve to alpha-amino acids and N-carbamoyl amino acids via selective catalytic processes. On the primitive Earth these N-carbamoyl amino acids combined with energetic molecules (NOx) may have been the core of a molecular engine producing peptides permanently and assuring their recycling and evolution.