Developing hierarchically structured biomaterials with tunable chemical and physical properties like those found in nature is critically important to regenerative medicine and studies on tissue morphogenesis. Despite advances in materials synthesis and assembly processes, our ability to control hierarchical assembly using fibrillar biomolecules remains limited. Here, we developed a bioinspired approach to create collagen-like materials through directed evolutionary screening and directed self-assembly. We first synthesized peptide amphiphiles by coupling phage display-identified collagen-like peptides to long-chain fatty acids. We then assembled the amphiphiles into diverse, hierarchically organized, nanofibrous structures using directed self-assembly based on liquid crystal flow and its controlled deposition. The resulting structures sustained and directed the growth of bone cells and hydroxyapatite biominerals. We believe these self-assembling collagen-like amphiphiles could prove useful in the structural design of tissue regenerating materials.

This paper presents a facile method for preparation of silica coated monodisperse superparamagnetic microsphere. Herein, monodisperse porous polystyrene-divinylbenzene microbeads were prepared by seeded emulsion polymerization and subsequently sulfonated with acetic acid/H2SO4. The as-prepared sulfonated macroporous beads were magnetized in presence of Fe2+/Fe3+under alkaline condition and were subjected to silica coating by sol-gel process, providing water compatibility, easily modifiable surface form, and chemical stability. FE-SEM, TEM, FT-IR, and TGA were employed to characterize the silica coated monodisperse magnetic beads (~7.5 μm). The proposed monodisperse magnetic beads can be used as mobile solid phase particles candidate for protein and DNA separation.

of SAM. We determined their Mg 2þ -dependent fractional populations and conformational dynamics, including state lifetimes, interconversion rate coefficients and equilibration timescales. Riboswitches with terminator and antiterminator folds were found to coexist under all conditions; SAM binding induced only a gradual increase in the population of terminator states. Conformational transitions were much faster with bound SAM, which may be crucial for offswitching during the brief decision window before expression of the downstream gene.