Amphiphilic block copolymers self-assemble into artificial membranes of enhanced strength and stability compared to lipid membranes and are still able to incorporate biological membrane proteins. Membrane fluidity is a key parameter for retaining function of incorporated proteins. In this study, lateral diffusion properties of membranes of diblock and triblock copolymers based on poly(2-methyl-2-oxazoline) and poly(dimethylsiloxane), with thicknesses between 6 and 21 nm, were systematically investigated. Z-scan fluorescence correlation spectroscopy was used to obtain highly accurate diffusion coefficients. The lateral diffusion coefficients (D) scale with the molecular weight of the hydrophobic block (M h ) for both diblock and triblock configurations as D ∝ M h −1.25 . A significant diffusion increase of diblocks compared to triblocks revealed that diffusion is primarily related to the different structural conformation of the macromolecules assembled in the membrane. Moreover, hindered diffusion for higher molecular weight copolymers was observed, indicating formation of domains due to interdigitation and entanglement, whereas free 2-D diffusion was detected for low molecular weight copolymers. These results represent a further step to understand structure-related membrane properties, i.e., density, stability, fluidity, permeability, etc. Additionally, the tracking of labeled membrane constituents embedded in artificial membranes offers crucial information about the desired functionality of bio-inspired supramolecular 3-D nanoassemblies.

We report a versatile approach for the design of substrate-independent low-fouling surfaces via mussel-inspired immobilisation of zwitterionic peptides. Using mussel-inspired polydopamine (PDA) coatings, zwitterionic glutamic acid- and lysine-based peptides were immobilised on various substrates, including noble metals, metal oxides, polymers, and semiconductors. The variation of surface chemistry and surface wettability upon surface treatment was monitored with X-ray photoelectron spectroscopy (XPS) and water contact angle measurements. Following peptide immobilisation, the surfaces became more hydrophilic due to the strong surface hydration compared with PDA-coated surfaces. The peptide-functionalised surfaces showed resistance to human blood serum adsorption and also effectively prevented the adhesion of gram-negative and gram-positive bacteria (i.e., Escherichia coli and Staphylococcus epidermidis) and mammalian cells (i.e., NIH 3T3 mouse embryonic fibroblast cells). The versatility of mussel-inspired chemistry combined with the unique biological nature and tunability of peptides allows for the design of low-fouling surfaces, making this a promising coating technique for various applications.

Slipping into a comfortable routine: Multilayered polymer thin films were assembled on particles immobilized in agarose by electrophoresis on the basis of various interactions. Core removal then led to robust capsules with different polymer compositions (see fluorescence image). This approach enables the versatile and routine assembly of nanometer‐ and micron‐sized capsules and coated particles with very few processing steps.

Self-organization of nanocomponents was mainly focused on solid nanoparticles, quantum dots, or liposomes to generate complex architectures with specific properties, but intrinsically limited or not developed enough, to mimic sophisticated structures with biological functions in cells. Here, we present a biomimetic strategy to self-organize synthetic nanocompartments (polymersomes) into clusters with controlled properties and topology by exploiting DNA hybridization to interconnect polymersomes. Molecular and external factors affecting the self-organization served to design clusters mimicking the connection of natural organelles: fine-tune of the distance between tethered polymersomes, different topologies, no fusion of clustered polymersomes, and no aggregation. Unexpected, extended DNA bridges that result from migration of the DNA strands inside the thick polymer membrane (about 12 nm) represent a key stability and control factor, not yet exploited for other synthetic nano-object networks. The replacement of the empty polymersomes with artificial organelles, already reported for single polymersome architecture, will provide an excellent platform for the development of artificial systems mimicking natural organelles or cells and represents a fundamental step in the engineering of molecular factories.

Simple cyclic disulfides under high tension mediate the uptake of giant substrates, that is, liposomes and polymersomes with diameters of up to 400 nm, into HeLa Kyoto cells. To place them at the surface of the vesicles, the strained disulfides were attached to the head-group of cationic amphiphiles. Bell-shaped dose response curves revealed self-activation of the strained amphiphiles by self-assembly into microdomains at low concentrations and self-inhibition by micelle formation at high concentrations. Poor colocalization of internalized vesicles with endosomes, lysosomes, and mitochondria indicate substantial release into the cytosol. The increasing activity with disulfide ring tension, inhibition with Ellman's reagent, and inactivity of maleimide and guanidinium controls outline a distinct mode of action that deserves further investigation and is promising for practical applications.

A promising approach for addressing a range of diseases lies in the delivery of functional biomacromolecules such as nucleic acids or proteins to cells. Polymers, peptides and the different shapes accessible through self-assembly of polymeric and peptidic amphiphiles have been widely explored as carriers and as containers for reactions on the nanoscale. These building blocks are particularly interesting, because several essential parameters such as physical characteristics, conditions for degradation or biocompatibility can be tuned to suit specific requirements. In this review, different three-dimensional architectures ranging from dendrimers and hyperbranched molecules to micelles, vesicles and nanoparticles assembled from synthetic polymers and peptides are discussed. It is focused on their function as a carrier for biologically active macromolecules, highlighting seminal examples from the current literature and pointing out the remaining and upcoming challenges in this important area of research.

Yellow fluorescent protein (YFP) is used as a mechanoresponsive layer at the fiber/resin interface in glass-fiber-reinforced composites. The protein loses its fluorescence when subjected to mechanical stress. Within the material, it reports interfacial shear debonding and barely visible impact damage by a transition from a fluorescent to a non-fluorescent state.

Bacterial laccase from Streptomyces coelicolor (SLAC) has been immobilised and orientated at promoter (pyrene and neocuproine)-modified electrodes productively both for direct electron transfer (ET) between the electrode and the T1 Cu site of SLAC and direct (unmediated) bio-electrocatalysis of dioxygen reduction. Its T1 Cu potential ranges between 471 and 318 mV versus the normal hydrogen electrode, at pH 5.5 and 8, respectively; this value is dependent both on the solution pH and electrode modification. In the presence of O2, Cu of the T2/T3 trinuclear centre is distinguished electrochemically at 748-623 mV. Depending on the promoter nature, different orientations of SLAC at pyrene- and neocuproine-modified electrodes can be followed from the kinetic analysis of the ET rates. Bio-electrocatalytic reduction of oxygen starts from the T1 Cu potentials of SLAC, and is most efficient at the promoter-modified electrodes, thereby demonstrating good performance both in neutral and basic media and in solutions with a high NaCl content, such as sea water. The obtained results allow consideration of a broader bioenergetic application of laccases as biocathodes operating directly in such environmental media as sea water and physiological fluids.