Light‐driven ATP regeneration systems combining ATP synthase and bacteriorhodopsin have been proposed as an energy supply in the field of synthetic biology. Energy is required to power biochemical reactions within artificially created reaction compartments like protocells, which are typically based on either lipid or polymer membranes. The insertion of membrane proteins into different hybrid membranes is delicate, and studies comparing these systems with liposomes are needed. Here we present a detailed study of membrane protein functionality in different hybrid compartments made of graft polymer PDMS‐g‐PEO and diblock copolymer PBd‐PEO. Activity of more than 90 % in lipid/polymer‐based hybrid vesicles could prove an excellent biocompatibility. A significant enhancement of long‐term stability (80 % remaining activity after 42 days) could be demonstrated in polymer/polymer‐based hybrids.

The design of efficient schemes for nicotinamide adenine dinucleotide (NAD) regeneration is essential for the development of enzymatic biotechnological processes in order to sustain continuous production. In line with our motivation for the encapsulation of redox cascades in liposomes to serve as microbioreactors, we developed a straightforward strategy for the interfacial oxidation of entrapped NADH by ferricyanide as an external electron acceptor. Instead of the commonly applied enzymatic regeneration methods, we employed a hydrophobic redox shuttle embedded in the liposome bilayer. Tetracyanoquinodimethane (TCNQ) mediated electron transfer across the membrane and thus allowed us to shortcut and emulate part of the electron transfer chain functionality without the involvement of membrane proteins. To describe the experimental system, we developed a mathematical model which allowed for the determination of rate constants and exhibited handy predictive utility.

Cortical actomyosin flows, among other mechanisms, scale up spontaneous symmetry breaking and thus play pivotal roles in cell differentiation, division, and motility. According to many model systems, myosin motor-induced local contractions of initially isotropic actomyosin cortices are nucleation points for generating cortical flows. However, the positive feedback mechanisms by which spontaneous contractions can be amplified towards large-scale directed flows remain mostly speculative. To investigate such a process on spherical surfaces, we reconstituted and confined initially isotropic minimal actomyosin cortices to the interfaces of emulsion droplets. The presence of ATP leads to myosin-induced local contractions that self-organize and amplify into directed large-scale actomyosin flows. By combining our experiments with theory, we found that the feedback mechanism leading to a coordinated directional motion of actomyosin clusters can be described as asymmetric cluster vibrations, caused by intrinsic non-isotropic ATP consumption with spatial confinement. We identified fingerprints of vibrational states as the basis of directed motions by tracking individual actomyosin clusters. These vibrations may represent a generic key driver of directed actomyosin flows under spatial confinement in vitro and in living systems.

The actomyosin cortex is involved in a range of many cellular processes like cell division, motility or shaping. To obtain this variety of functionalities the membrane-bound actin mesh has to be reconstituted by the motor protein myosin. But little is known about the underlying mechanism, which control the different tasks. An underlying in vitro study of a synthetic actomyosin cortex has shown that the cortex organizes into spatial clusters for certain ATP concentrations. Here we develop a curvilinear model that captures the viscoelastic material behavior and the kinetics of the myosin cross bridge. Further, we suggest a formulation for the active contractile stress produced by the motor protein myosin. We demonstrate that the spatial pattern generated by the curvilinear model is consistent with the experimental observations, including mesh clustering due to contractile forces and an absence of contraction for low and high ATP concentrations. Additionally we show that the cluster positioning can be tuned by the ATP-gradient.

Cortical actomyosin dynamics and flows play pivotal roles in eukaryotic cells, e.g. for cell motility, cell division and chiral morphogenesis during early embryogenesis of multicellular organisms. For many model systems myosin motors have been proposed to play a key role in the generation of cortical actomyosin dynamics and flows. However, little is known about the mechanisms behind these actomyosin flows. We reconstituted and confined minimal actin cortices inside water in oil droplets. These spherically confined actomyosin cortices exhibit directional actomyosin flow-like motions upon ATP induced contractility of the myosin motors. By combining our experiments with a theoretical description, we found that the observed direct motion of the actomyosin clusters arises from vibrations within the individual actomyosin clusters. By tracking actin clusters, we detected fingerprints of vibrational states driving their directed motions in the spherical confinement. These vibrations may provide a mechanism driving cortical actomyosin dynamics and flows in living systems.

The ability of designing biosynthetic systems with well‐defined functional biomodules from scratch is an ambitious and revolutionary goal to deliver innovative, engineered solutions to future challenges in biotechnology and process systems engineering. In this work, several key challenges including modularization, functional biomodule identification, and assembly are discussed. In addition, an in silico protocell modeling approach is presented as a foundation for a computational model‐based toolkit for rational analysis and modular design of biomimetic systems.

Cortical actomyosin flows, among other mechanisms, scale up spontaneous symmetry breaking and thus play pivotal roles in cell differentiation, division, and motility. According to many model systems, myosin motor-induced local contractions of initially isotropic actomyosin cortices are nucleation points for generating cortical flows. However, the positive feedback mechanisms by which spontaneous contractions can be amplified towards large-scale directed flows remain mostly speculative. To investigate such a process on spherical surfaces, we reconstituted and confined initially isotropic minimal actomyosin cortices to the interfaces of emulsion droplets. The presence of ATP leads to myosin-induced local contractions that self-organize and amplify into directed, large-scale actomyosin flows. By combining our experiments with theory, we found that the feedback mechanism leading to a coordinated, directional motion of actomyosin clusters can be described as asymmetric cluster vibrations, caused by intrinsic non-isotropic ATP consumption, in conjunction with spatial confinement. By tracking individual actomyosin clusters, we identified fingerprints of vibrational states as the basis of directed motions. These vibrations may represent a generic key driver of directed actomyosin flows under spatial confinement in vitro and in living systems.

The freezing speed influences the growth and spatial distribution of ice inf frozen meat. The formation of ice crystals dehydrates the fibres and can damage the cell structure. This influences the drip loss after thawing and reduces tenderness, which is an important eating characteristic of red meat. A better understanding of ice formation and an efficient method for analysing ice distribution can lead to improved freezing processes in food production. This work demonstrates X-ray computed tomography as a novel method suitable for determining and visualising the ice volume fraction in frozen meat, which is important because ice formation has consequences for meat quality (drip loss on thawing, loss of juiciness and tenderness after cooking). The results obtained are in agreement with the phenomenological predictions of the literature and extend the known microscopy methods with a non-destructive and time efficient analysis technique that provides information about the amount of ice formed and its spatial distribution in frozen meat.