The mechanism of spontaneous assembly of microscale compartments is a central question for the origin of life, and has technological repercussions in diverse areas such as materials science, catalysis, biotechnology and biomedicine. Such compartments need to be semipermeable, structurally robust and capable of housing assemblages of functional components for internalized chemical transformations. In principle, proteins should be ideal building blocks for the construction of membrane-bound compartments but protein vesicles with cell-like properties are extremely rare. Here we present an approach to the interfacial assembly of protein-based micro-compartments (proteinosomes) that are delineated by a semi-permeable, stimulus-responsive, enzymatically active, elastic membrane consisting of a closely packed monolayer of conjugated protein-polymer building blocks. The proteinosomes can be dispersed in oil or water, thermally cycled to temperatures of 70°C, and partially dried and re-inflated without loss of structural integrity. As a consequence, they exhibit protocellular properties such as guest molecule encapsulation, selective permeability, gene-directed protein synthesis and membrane-gated internalized enzyme catalysis.

No abstract

Atomically thick graphene layers produced from graphite reveal unique electro-thermal, and mechanical properties, [1][2][3][4][5][6][7] and are considered to have a wide range of applications in nanoelectronics, catalysis and biosensing. [1,3,[8][9][10] Graphene monolayers exhibiting exceptional electron/hole carrier mobility have been prepared by mechanical exfoliation of highly ordered pyrolytic graphite, [1,3] by epitaxial growth using chemical vapour deposition of hydrocarbons onto silicon carbide, [11] or via thermal fusion of polycyclic aromatic hydrocarbons.[12] These methods are constrained by low yields and processing limitations, and more practical approaches based on the chemical [6,12,13] or thermal [15,16] reduction of exfoliated sheets of oxidised graphite (graphene oxide, GO) have been developed. High yields of GO monolayers, 0.78 nm in thickness, can be readily prepared by treatment of graphite under strongly acidic and oxidising conditions. [17][18][19] The GO single sheets can be readily dispersed in water and mounted onto substrates using spin-, dip-and spray-coating techniques, and reduced in situ to produce isolated graphene monolayers or transparent 2D films [20][21][22][23][24] with conductivities ranging from as low as 2 S cm À1 , [20] or 23 S cm À1, [15] to a value of 550 S cm À1 for a 10 nm-thick film, [20] comparable with polycrystalline graphite (1250 S cm À1).[25] Alternatively, aqueous dispersions of GO oxide can be chemically reduced directly to produce aggregated sols of graphene sheets that can be assembled into graphene thin films with a typical conductivity of 72 S cm À1. [26] Moreover, by undertaking the reduction step in the presence of poly(sodium 4-styrenesulfonate), [13] or pyrene butyrate, [14] or exploiting electrostatic repulsions between adjacent sheets in an alkaline medium, [26] stable aqueous dispersions of coated graphene monolayers have been produced. Similar approaches have been used to prepare stable graphene dispersions in polar organic solvents by chemical reduction of GO sheets functionalized with hydrophobic residues such as alkylamines, [27] phenyl isocyanate [6] or anhydrous hydrazine. [28] Alternatively, Coleman and coworkers [29] have recently prepared graphene dispersions by ultrasonicating graphite powders in various solvents, for example, N-methylpyrrolidinone, followed by subsequent fractionation using low-speed centrifugation to produce sols comprising single and multilayered graphene sheets. Interestingly, thin films produced from the above dispersions showed conductivity values of $65 S cm À1, comparable to that of chemically reduced graphene oxide paper.Recent studies have demonstrated that hydrophobic carbon nanotubes (CNTs) can be successfully functionalized using single-stranded (ss) DNA to produce novel nanocomposites with potential applications in nanoelectronics and bionanotechnology. [30,31] Adsorption of the biomolecules onto the surface of the CNTs is facilitated by non-covalent p-p stacking interactions involving both purine and pyrimidi...

No abstract

No abstract

The design and construction of higher-order structure and function in proteinosome microcompartments enclosed by a cross-linked membrane of amphiphilic bovine serum albumin/poly(N-isopropylacrylamide) (BSA-NH2/PNIPAAm) nanoconjugates is described. Three structure/function relationships are investigated: (i) differential chemical cross-linking for the control of membrane disassembly and regulated release of encapsulated genetic polymers; (ii) enzyme-mediated hydrogel structuring of the internal microenvironment to increase mechanical robustness and generate a molecularly crowded reaction environment; and (iii) self-production of a membrane-enclosing outer hydrogel wall for generating protease-resistant forms of the protein-polymer protocells. Our results highlight the potential of integrating aspects of supramolecular and polymer chemistry into the design and construction of novel bioinspired microcompartments as a step toward small-scale materials systems based on synthetic cellularity.

No abstract

No abstract