Search

Self-assembly formation of sodium salts of three N-acyl peptide surfactants, sodium N-(4-n-dodecyloxybenzoyl)-L-alyl-L-valinate (SDBAV), L-valyl-L-alaninate (SDBVA), and l-valyl-L-valinate (SDBVV) are investigated. They are shown to spontaneously form large vesicles in dilute aqueous solution and the cac values of the amphiphiles are very low which implies that the free energy of formation of vesicles is lower.

The equilibrium constants (K(sub de) for the dehydration of hydrates of benzene, naphthalene, phenanthrene and anthracene were reported in this study. The results illustrated the usefulness of a substituent treatment for extending the range of currently available free energies of formation.

Research was conducted to examine the host-guest complexation of 2-(4'-aminophenyl)- and 2-(4'(N,N'-dimethylamino)phenyl)benzothiazole with beta-cyclodextrin in aqueous solution using fluorescence spectroscopy. To confirm complexation and to estimate the orientation of the guest molecule in the cyclodextrin cavity, the induced circular dichroic spectra of the inclusion complexes were also calculated. Results indicate the complexation of ClO4- with beta-cyclodextrin.

A study was conducted to examine the self-assembly, surface activity and aggregation behavior of an amino acid-based zwitterionic amphiphile N-(2-hydroxy-dodecyl)-L-valine in aqueous solutions. The results obtained provide insight into the two breaks in the surface tension vs concentration exhibited by the amphiphile and the formation of spherical vesicles, separated tubules, and tubules with multiple Y-type junctions from dilute to moderately concentrated solution.

The physiochemical properties and the microstructure formation of the surfactant mixtures of sodium N-(2-(n-dodecylamino)ethanoyl)-L-alaninate and sodium dodecyl sulfate (SDS) in aqueous solutions are examined. The size and shape of microstrucures were determined by using different techniques like fluorescence probe, transmission electron micrography and neutorn scattering.

A series of β-amino acid containing tripeptides has been designed and synthesized in order to develop oligopeptide-based, thermoreversible, pH-sensitive, and proteolytically stable hydrogels. The Fmoc [N-(fluorenyl-9-methoxycarbonyl)]-protected tripeptides were found to produce hydrogels in both pH 7 and 2 buffers at a very low concentration (<0.2% w/v). It has been shown that the Fmoc group plays an important role in the gelation process. Also a dependence of gelation ability on hydrophobicity of the side chain of the Fmoc-protected α-amino acid was observed. The effect of the addition of inorganic salts on the gelation process was investigated as well. Spectroscopic studies indicated formation of J-aggregates through π-π stacking interactions between Fmoc groups in solution as well as in the gel state. In the gel phase, these self-assembling tripeptides form long interconnected nanofibrils leading to the formation of 3-dimensional network structure. The hydrogels were characterized by various techniques, including field emission electron microscopy, transmission electron microscopy, atomic force microscopy, rheology, Fourier transform IR, circular dichroism (CD), and wide-angle X-ray diffraction (WAXD) spectroscopy. The CD studies and WAXD analyses show an antiparallel β-sheet structure in the gel state. l-Phenylalanine and l-tyrosine containing tripeptides formed helical aggregates with handedness opposite to those containing l-valine and l-leucine residues. The mechanical stability of the hydrogels was found to depend on the hydrophobicity of the side chain of the tripeptide as well as on the pH of the solution. Also, the tripeptides exhibit in vitro proteolytic stability against proteinase K enzyme. [ABSTRACT FROM AUTHOR]