The structure of lysozyme-sodium dodecyl sulfate (SDS) complexes in solution is studied using small-angle X-ray scattering (SAXS). The SAXS data cannot be explained by the necklace and bead model for unfolded polypeptide chain interspersed with surfactant micelles. For the protein and surfactant concentrations used in the study, there is only marginal growth of SDS micelles as they complex with the protein. Being a small and rather rigid protein, lysozyme can penetrate the micellar core which is occupied by flexible and disordered paraffin chains and also the shell occupied by the hydrated head groups. A partially embedded swollen micellar model seems appropriate and describes well the scattering data. The SAXS intensity profiles are analyzed by considering the change in the electron scattering length density of the micellar core and shell due to complexation with protein and treating the intermicellar interaction using rescaled mean spherical approximation (RMSA) for charged spheres.
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http://dx.doi.org/10.1016/j.jcis.2008.09.012 | DOI Listing |
J Phys Chem B
January 2025
Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400094, India.
Introduction of non-DLVO forces by nonionic surfactants brings about fascinating changes in the phase behavior of silica nanosuspensions. We show here that alterations in the interaction and wetting properties of negatively charged silica nanoparticles (Ludox® LS) in the presence of polyethylene oxide-polypropylene oxide-polyethylene oxide-based triblock copolymers called Pluronics lead to the formation of stable o/w Pickering emulsions and interparticle attraction-induced thermoresponsive liquid-liquid phase separations. The results make interesting comparisons with those reported for Ludox® TM nanosuspensions comprising larger silica nanoparticles.
View Article and Find Full Text PDFJ Control Release
January 2025
Centre de Biophysique Moléculaire, CBM, CNRS UPR4301, Orléans, France. Electronic address:
The development of lipid-based mRNA delivery systems has significantly facilitated recent advances in mRNA-based therapeutics. Liposomes, as the pioneering class of mRNA vectors, continue to lead in clinical trials. We previously developed a histidylated liposome that demonstrated efficient nucleic acid delivery.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Institute of Theoretical and Applied Mechanics of the Czech Academy of Sciences, Centre Telč, 58856 Telč, Czech Republic.
The time-evolution of dynamics as well as microstructure and mechanical response of phosphate-based geopolymers was probed using x-ray photon correlation spectroscopy and rheological tests. The analyzed relaxation processes in the freshly prepared geopolymer mixes evidenced a q-independent mode of the autocorrelation function, ascribed to density fluctuations of the already established molecular network, undergoing reconfiguration without significant mass transport. Upon curing, the detected motions are localized and depict a system evolving toward structural arrest dominated by slower hyperdiffusive dynamics, characterized by a compressed exponential regime, pointing to a structural relaxation process subjected to internal stresses, in a context of marked dynamical and structural heterogeneity.
View Article and Find Full Text PDFCurr Protoc
January 2025
Czech Metrology Institute, Brno, Czech Republic.
Atomic force microscopy (AFM) has recently received increasing interest in molecular biology. This technique allows quick and reliable detection of biomolecules. However, studying RNA-protein complexes using AFM poses significant challenges.
View Article and Find Full Text PDFEnviron Sci Technol
January 2025
Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States.
Supercritical (sc) CO in geologic carbon sequestration (GCS) can chemically and mechanically deteriorate wellbore cement, raising concerns for long-term operations. In contrast to the conventional view of "sulfate attack" on cement, we found that adding 0.15 M sulfate to the acidic brine can significantly reduce the impact of scCO attack on Portland cement, resulting in stronger cement than that found in a sulfate-free system.
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