The secretion and reversible assembly of an extracellular-like matrix by enzyme-active inorganic protocells (colloidosomes) is described. Addition of N-fluorenyl-methoxycarbonyl-tyrosine-(O)-phosphate to an aqueous suspension of alkaline phosphatase-containing colloidosomes results in molecular uptake and dephosphorylation to produce a time-dependent sequence of supramolecular hydrogel motifs (outer membrane wall, cytoskeletal-like interior and extra-protocellular matrix) that are integrated and remodelled within the microcapsule architecture and surrounding environment. Heat-induced disassembly of the extra-protocellular matrix followed by cooling produces colloidosomes with a densely packed hydrogel interior. These procedures are exploited for the fabrication of nested colloidosomes with spatially delineated regions of hydrogelation.

Morphologically complex amorphous calcium phosphate nanostructures are synthesized within supersaturated water-in-oil miniemulsions stabilized by a mixture of a calcium bis­(2-ethylhexyl)­phosphate (Ca­(DEHP)2) surfactant and poly­(ethylene oxide)19-poly­(propylene oxide)69-poly­(ethylene oxide)19 (P123) triblock copolymer. Solvent evaporation at room temperature results in self-supporting viscous organogels comprising an interconnected network of calcium phosphate nanofilaments embedded within a continuous polymer/surfactant matrix. The P123/DEHP/calcium phosphate organogels are employed as a bioactive filler for the occlusion of exposed dentine tubules using a standard bovine tooth model.

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Dentine sensitivity is a dental problem common in individuals aged between 20 and 50 years. The most effective treatment method involves occluding the exposed dental tubules. This study focused on the synthesis of calcium phosphate nanoparticles in the form of gel to use as a proof of concept for home-treatment of sensitive teeth. In this study, calcium phosphate nanoparticles were prepared using emulsion method, in which oleic fatty acid was employed as an external phase, and sodium dodecyl sulphate (SDS) was used as a surfactant to form water-in-oil nanodroplets. Finally, in order to facilitate gel formation, the gelatin solution was introduced at the final step. The amount of gelatin varied from 5 to 15 percent by weight, which was found to have an effect on the gels’ properties and the size of calcium phosphate nanoparticles embedded in gel. Based on the characterization, the calcium phosphate nanoparticles were spherical in shape, though the size decreased as the amount of gelatin increased. The gel embedding smallest nanoparticle, that is, gel-15%G, was successfully proven to be non-toxic and able to fully occlude the dentine tubules only after overnight application. According to acid challenge, the occluded materials can resist to acid solution via redissolvation and reprecipitaion process.