Positional Assembly of Enzymes in Polymersome Nanoreactors for Cascade Reactions

Precise In Situ Modulation of Local Liquid Chemistry via Electron Irradiation in Nanoreactors Based on Graphene Liquid Cells

A controlled electron-water radiolysis process is used to generate predictable concentrations of radical and ionic species in graphene liquid cells, allowing the concept of a nanoscale chemical reactor. A differential scanning technique is used to generate the desired time- and space-varying electron dose rate. Precise control of the local concentration of H2 , the dominant radiolysis species, is demonstrated experimentally at the nanometer scale.

Enzymatic reactions in confined environments

Within each biological cell, surface- and volume-confined enzymes control a highly complex network of chemical reactions. These reactions are efficient, timely, and spatially defined. Efforts to transfer such appealing features to in vitro systems have led to several successful examples of chemical reactions catalysed by isolated and immobilized enzymes. In most cases, these enzymes are either bound or adsorbed to an insoluble support, physically trapped in a macromolecular network, or encapsulated within compartments. Advanced applications of enzymatic cascade reactions with immobilized enzymes include enzymatic fuel cells and enzymatic nanoreactors, both for in vitro and possible in vivo applications. In this Review, we discuss some of the general principles of enzymatic reactions confined on surfaces, at interfaces, and inside small volumes. We also highlight the similarities and differences between the in vivo and in vitro cases and attempt to critically evaluate some of the necessary future steps to improve our fundamental understanding of these systems.

Compartmentalization and Transport in Synthetic Vesicles

Nanoscale vesicles have become a popular tool in life sciences. Besides liposomes that are generated from phospholipids of natural origin, polymersomes fabricated of synthetic block copolymers enjoy increasing popularity, as they represent more versatile membrane building blocks that can be selected based on their specific physicochemical properties, such as permeability, stability, or chemical reactivity. In this review, we focus on the application of simple and nested artificial vesicles in synthetic biology. First, we provide an introduction into the utilization of multicompartmented vesosomes as compartmentalized nanoscale bioreactors. In the bottom-up development of protocells from vesicular nanoreactors, the specific exchange of pathway intermediates across compartment boundaries represents a bottleneck for future studies. To date, most compartmented bioreactors rely on unspecific exchange of substrates and products. This is either based on changes in permeability of the coblock polymer shell by physicochemical triggers or by the incorporation of unspecific porin proteins into the vesicle membrane. Since the incorporation of membrane transport proteins into simple and nested artificial vesicles offers the potential for specific exchange of substances between subcompartments, it opens new vistas in the design of protocells. Therefore, we devote the main part of the review to summarize the technical advances in the use of phospholipids and block copolymers for the reconstitution of membrane proteins.

Broadening the range of vesicle formation by heating

Vesicles of amphiphilic block copolymers have been extensively studied, but surprisingly few studies used high temperature to promote the polymer shape evolution towards vesicles.

The origins of life: old problems, new chemistries

Synthetic life: the origin of life on the early Earth, and the ex novo transition of non-living matter to artificial living systems are deep scientific challenges that provide a context for the development of new chemistries with unknown technological consequences. This Essay attempts to re-frame some of the epistemological difficulties associated with these questions into an integrative framework of proto-life science. Chemistry is at the heart of this endeavour.

Constructing spatially separated multienzyme system through bioadhesion-assisted bio-inspired mineralization for efficient carbon dioxide conversion

A facile and green bioadhesion-assisted bio-inspired mineralization (BABM) approach is proposed to construct spatially separated multienzyme system for conversion of carbon dioxide to formaldehyde. Specifically, formate dehydrogenase is entrapped accompanying the formation of titania nanoparticles (NPs) through bio-inspired titanification. After in situ surface functionalization of NPs with oligodopa, formaldehyde dehydrogenase is immobilized on the surface of NPs through amine-catechol adduct reaction. Compared to co-immobilized and free multienzyme system, the spatially separated multienzyme system exhibits significantly enhanced formaldehyde yield, selectivity and initial specific activity. The influence of particle size on the enzyme activity reveals that the formaldehyde yield (80.9%, 52.9%, 46.4%), selectivity (92.7%, 86.6%, 85.1%) and initial specific activity (1.87, 1.31, 0.29 U mg(-1)) all decreased as the NPs particle size increased from 75, 175 to 375 nm. After storing for 20 days at 4 °C, this multienzyme system retains as high as 70% of its initial activity.