Creating unusual nanostructures: Self-assembly often occurs when dissimilar molecular fragments are forced together by covalent bonding. Surfactants or block copolymers are two common examples. Huang et al. grafted four different nanoparticles, based on polyhedral oligomeric silsesquioxanes with slightly different compositions, onto a single tetrahedal core (see the Perspective by Yang). Depending on the type of nanoparticle, they assembled into a range of defined, ordered supramolecular lattices similar to a range of metal alloys. These include phases that have higher coordination numbers than usually found in the packing of spherical objects. Science , this issue p. 424; see also p. 396

Significance: Advances in tissue engineering and regenerative medicine have created a need for new biomaterial scaffolds that facilitate cell encapsulation and transplantation. Here we present an approach to the synthesis of artificial protein scaffolds that form spontaneously under physiological conditions. These protein hydrogels may be designed to include cell-adhesion ligands, protease cleavage sites, and full-length globular proteins that carry the information needed to program the behavior of encapsulated cells. We demonstrate the approach by encapsulating mouse embryonic stem cells in a protein scaffold that includes leukemia inhibitory factor (LIF); the encapsulated cells remain pluripotent in the absence of added LIF. The results presented here illustrate a versatile strategy for the creation of information-rich biomaterials.

Significance: How far can we push self-assembly toward unusual nanostructures? Frank–Kasper and quasicrystal phases represent unconventional phases of ordered spheroids originally identified in metal alloys. We report that Frank–Kasper and quasicrystal phases and their transition sequence are observed in one-component giant surfactants by introducing variations in molecular geometry. Both X-ray scattering and electron microscopy techniques are used to identify the self-assembled nanostructures. Combining molecular dynamics simulations, we attribute the appearance of these phases to molecular geometry as a result of tail number variation. Our findings lay the foundation for rational design of unconventional soft-matter phases and for exploiting them for unusual properties and functions.