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Novel highly functionalized hybrid organic-inorganic materials were synthesized by polycondensation of bis[3-(trimethoxysilyl)propyl]amine in presence of cationic and anionic surfactants. Reaction media strongly affected gelation time. Thus, in basic media gelation occurred immediately while acid increased gelation time. Material structures were studied by IR spectroscopy, porosimetry, XRD, and SAXS methods. In spite of the absence of an inorganic linker, obtained bridged silsesquioxanes had mesoporous structure. A material prepared in the presence of dodecylamine as a template had higher surface area and narrow pore size distribution while the use of sodium dodecylbenzene sulfate resulted in formation of mesopores with wide size ranges. Accessibility of surface amine groups in silsesquioxanes was studied for molecules of acidic nature and different sizes: HCl, CO2 and picric acid. High contents of accessible amine groups in these materials make them prospective adsorbents for post-combustion CO2 capture.

Yes / Understanding the structure-property relationships of drug delivery system (DDS) components is critical for their development and the prediction of bodily performance. This study investigates the effects of introducing polyethylene oxide (PEO) homopolymers, over a wide range of molecular weights, into Pluronic injectable smart hydrogel formulations. These smart DDSs promise to enhance patient compliance, reduce adverse effects and dosing frequency. Pharmaceutically, Pluronic systems are attractive due to their unique sol-gel phase transition in the body, biocompatibility, safety and ease of injectability as solutions before transforming into gel matrices at body temperature. This paper presents a systematic and comprehensive evaluation of gelation and the interplay of microscopic and macroscopic properties under both equilibrium and non-equilibrium conditions in controlled environments, as measured by rheology in conjunction with time-resolved Small Angle Neutron Scattering (SANS). The non-equilibrium conditions investigated in this work offer a better understanding of the two polymeric systems’ complex interactions affecting the matrix thermo-rheological behaviour and structure and therefore the future release of an active pharmaceutical ingredient from the injectable DDS.

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<div>Large protein molecules are abundant in biological cells but are very difficult to study in physiological conditions due to molecular disorder. For large proteins, most structural information is obtained in crystalline states which can be achieved in certain conditions at very low temperature. X-ray and neutron crystallography methods can then be used for determination of crystalline structures at atomic level. However, in solution at room or physiological temperatures such highly resolved descriptions cannot be obtained except in very few cases. Scattering methods that can be used to study this type of structures at room temperature include small-angle x-ray and neutron scattering. These methods are used here to study two distinct proteins that are both classified as glycoproteins, which are a large class of proteins with diverse biological functions. In this study, two specific plasma glycoproteins were used: Fibrinogen (340 kDa) and Alpha 1-Antitrypsin or A1AT (52 kDa). These proteins have been chosen based on the fact that they have a propensity to form very large molecular aggregates due to their tendency to polymerize. One goal of this project is to show that for such complex structures, a combination of scattering methods that include SAXS, SANS, and DLS can address important structural and interaction questions despite the fact that atomic resolution cannot be obtained as in crystallography. A1AT protein has been shown to have protective roles of lung cells against emphysema, while fibrinogen is a major factor in the blood clotting process. A systematic approach to study these proteins interactions with lipid membranes and other proteins, using contrast-matching small-angle neutron scattering (SANS), small angle x-ray scattering (SAXS) and dynamic light scattering (DLS), is presented here. A series of structural reference points for each protein in solution were determined by performing measurements under osmotic stress controlled by the addition of polyethylene glycol-1,500 MW (PEG 1500) in the samples. Osmotic pressure changes the free energy of the molecular mixture and has consequences on the structure and the interaction of molecular aggregates. In particular, the measured radius of gyration (Rg) for A1AT shows a sharp structural transition when the concentration of PEG 1500 is between 33 wt\% and 36 wt\%. Similarly, a significant structural change was observed for fibrinogen when the concentration of PEG 1500 was above 40 wt\%. This analysis is applied to a study of A1AT interacting with lipid membranes and to a study of fibrinogen polymerization in the presence of the enzyme thrombin, which catalyzes the formation of blood clots. The experimental approach presented here and the applications to specific questions show that an appropriate combination of scattering methods can produce useful information on the behavior and the interactions of large protein systems in physiological conditions despite the lower resolution compared to crystallography.</div>