Swelling and Orientation Behavior of End-Grafted Polymer Chains by In Situ Attenuated Total Reflection Fourier Transform Infrared Spectroscopy Complementing Ellipsometry.

The literature lacks established concrete parameters for assigning grafted chain regimes. In this context, dichroic attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and ellipsometry were used complementarily, offering new opportunities for conformational analysis of end-grafted polymer chains. Especially polymer chain orientation was studied as a new parameter, among others, for proper chain regime assignment in this report.

Influence of the Sequence Motive Repeating Number on Protein Folding in Spider Silk Protein Films.

Like multiblock copolymers, spider silk proteins are built of repetitive sequence motives. One prominent repetitive motif is based on the consensus sequence of spidroin 4 of the spider ADF4. The number of the repeating sequence motives (C) determines the molecular weight of the recombinant ADF4-based, engineered spider silk protein denoted as eADF4(C).

β-Sheet Structure Formation within Binary Blends of Two Spider Silk Related Peptides.

Intrinsically disordered proteins (IDPs) play an important role in molecular biology and medicine because their induced folding can lead to so-called conformational diseases, where β-amyloids play an important role. Still, the molecular folding process into the different substructures, such as parallel/antiparallel or extended β-sheet/crossed β-sheet is not fully understood. The recombinant spider silk protein eADF4(Cx) consisting of repeating modules C, which are composed of a crystalline (pep-c) and an amorphous peptide sequence (pep-a), can be used as a model system for IDP since it can assemble into similar structures.

Dichroic Fourier Transform Infrared Spectroscopy Characterization of the β-Sheet Orientation in Spider Silk Films on Silicon Substrates.

Orientation analysis of the β-sheet structure within films of the established recombinant spider silk protein eADF4(C16) was performed using a concept based on dichroic transmission- and attenuated total reflection-Fourier transform infrared spectroscopy, lineshape analysis, assignment of amide I components to specific vibration modes, and transition dipole moment directions of β-sheet structures. Based on the experimental dichroic ratio , the order parameter of β-sheet structures was calculated with respect to uniaxial orientation. Films of eADF4(C16) were deposited on untexturized (Si) and unidirectionally scratched silicon substrates (Si-sc) and post-treated with MeOH vapor.

Effects of Chain Length of Chitosan Oligosaccharides on Solution Properties and Complexation with siRNA.

In the context of gene delivery, chitosan has been widely used as a safe and effective polycation to complex DNA, RNA and more recently, siRNA. However, much less attention has been paid to chitosan oligosaccharides (COS) despite their biological properties. This study proposed to carry out a physicochemical study of COS varying in degree of polymerization (DP) from 5 to 50, both from the point of view of the solution properties and the complexing behavior with siRNA.