Aggregates of charged amphiphilic molecules have been found to access a structure at elevated temperature that templates alignment of supramolecular fibrils over macroscopic scales. The thermal pathway leads to a lamellar plaque structure with fibrous texture that breaks upon cooling into large arrays of aligned nanoscale fibres and forms a strongly birefringent liquid. By manually dragging this liquid crystal from a pipette onto salty media, it is possible to extend this alignment over centimetres in noodle-shaped viscoelastic strings. Using this approach, the solution of supramolecular filaments can be mixed with cells at physiological temperatures to form monodomain gels of aligned cells and filaments. The nature of the self-assembly process and its biocompatibility would allow formation of cellular wires in situ that have any length and customized peptide compositions for use in biological applications.

The mechanical properties and water permeability of hierarchical self-assembling membranes and sacs formed from oppositely charged high molecular weight hyaluronic acid (HA) and small molecule peptide amphiphiles (PAs) were studied. Techniques to make reproducible 2D planar membranes and 3D spherical sacs from these materials were developed while membrane inflation and osmotic swelling were used to quantify the mechanical properties and water permeability of these structures. It was found that incubation time and concentration of HA used had an effect on the area modulus and water permeability of the membranes. These factors also affected the kinetics of membrane growth as evidenced in SEM micrographs, which showed differences in the structure. Area modulus of membranes changed from about 6 N m À1 for the lower weight percent HA system at the shortest incubation time of 3 minutes, up to 12 N m À1 for the higher weight percent HA system at the longest incubation time of 60 minutes. Water permeability decreased with incubation time, but the lower weight percent HA system showed a lower water permeability when compared to the higher weight percent HA system at the same incubation time. This type of characterization and understanding of the structure-property relationships in self-assembling systems are necessary steps in both using these structures for specific applications and applying this knowledge to design new and better materials in the future.

Self-assembly in the presence of external forces is an adaptive, directed organization of molecular components under nonequilibrium conditions. While forces may be generated as a result of spontaneous interactions among components of a system, intervention with external forces can significantly alter the final outcome of self-assembly. Superimposing these intrinsic and extrinsic forces provides greater degrees of freedom to control the structure and function of self-assembling materials. In this work we investigate the role of electric fields during the dynamic self-assembly of a negatively charged polyelectrolyte and a positively charged peptide amphiphile in water leading to the formation of an ordered membrane. In the absence of electric fields, contact between the two solutions of oppositely charged molecules triggers the growth of closed membranes with vertically oriented fibrils that encapsulate the polyelectrolyte solution. This process of self-assembly is intrinsically driven by excess osmotic pressure of counterions, and the electric field is found to modify the kinetics of membrane formation, and also its morphology and properties. Depending on the strength and orientation of the field we observe a significant increase or decrease of up to nearly 100% in membrane thickness, as well as the controlled rotation of nanofiber growth direction by 90 degrees, resulting in a significant increase in mechanical stiffness. These results suggest the possibility of using electric fields to control structure in self-assembly processes involving diffusion of oppositely charged molecules.

Characterization of tissue explant ultrastructure, particle size, and swelling revealed differences in the materials. BGP, in addition to absorbing fluid and concentrating clotting factors and platelets, integrate into the clot and stabilize the fibrin matrix. BGP have advantages over MPH in terms of speed and efficacy. BGP are a favorable biomaterial for further research that greatly improve the limited efficacy of powdered hemostats.

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