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The mineralized extracellular matrix (ECM) of bone is essential in vertebrates to provide structure, locomotion, and protect vital organs, while also acting as a calcium and phosphate reservoir to maintain homeostasis. Bone's structure comprises mainly structural collagen fibrils, hydroxyapatite nanocrystals and water, and it is the organization of the densely-packed collagen matrix that directs the organization of the mineral crystallites. Biogenic mineralization occurs when osteoblasts release "mineral bearing globules" which fuse into the preformed collagen matrix, and upon crystallization of this amorphous precursor, the fibrils become embedded with [001] oriented nanocrystals of hydroxyapatite. Our prior work has shown that this nanostructured organization of bone can be reproduced in vitro using the polymer-induced liquid-precursor (PILP) process. In this report, our focus is on using biomimetic processing to recreate both the nano- and micro-structure of lamellar bone. We first applied molecular crowding techniques to acidic, type-I collagen solutions to form dense, liquid crystalline collagen (LCC) scaffolds with cholesteric order. We subsequently mineralized these LCCs via the PILP process to achieve a high degree of intrafibrillar mineral, with compositions and organization similar to that of native bone and with a "lamellar" microstructure generated by the twisting LCC template. In depth characterization of the nano- and micro-structure was performed, including optical and electron microscopy, X-ray and electron diffraction, and thermogravimetric analyses. The results of this work lead us closer to our goal of developing hierarchically structured, collagen-hydroxyapatite composites which can serve as fully synthetic, bioresorbable, load-bearing bone substitutes that are remodeled by the native BRU.

Phase behavior, solubilization, and phase transition of a microemulsion system stabilized by a castor oil-based novel surfactant (sodium methyl ester sulfonate) and cosurfactant (propan-2-ol) were investigated for effective application in oil recovery processes. A pseudoternary phase diagram showed the existence of different phases (S/L phase, Winsor I, Winsor II, Winsor III, and Winsor IV) by conventional titration method. With an increase in the cosurfactant-to-surfactant ratio (K cs), the region under the Winsor III phase was found to increase. An increase in cosurfactant content in the system mixture improved interactions of the surfactant with oil and water in the microemulsion phase, thereby reducing molecular aggregations in solution. At optimal salinity, equal amounts of oil and water were solubilized in a microemulsion in the Winsor III systems and showed ultralow interfacial tension (IFT) values on the order of 10–3 to 10–4 mN/m. Phase dilution studies revealed that the microemulsion systems formed were thermodynamically stable. Salinity increased the relative phase volume of a middle-phase microemulsion, whereas an increase in water content reduced the middle phase volume fractions in the Winsor III systems. Phase transition data were analyzed and fitted using empirical relationships. An increase in salinity and brine content caused phase transformation from Winsor I to Winsor II via Winsor III. However, an increase in temperature showed reverse phase transformation from Winsor II to Winsor III.