Enzyme‐filled polystyrene‐b‐poly(3‐(isocyano‐L‐alanyl‐aminoethyl)thiophene) (PS‐b‐PIAT) nanoreactors are encapsulated together with free enzymes and substrates in a larger polybutadiene‐b‐poly(ethylene oxide) (PB‐b‐PEO) polymersome, forming a multicompartmentalized structure, which shows structural resemblance to the cell and its organelles. An original cofactor‐dependent three‐enzyme cascade reaction is performed, using either compatible or incompatible enzymes, which takes place across multiple compartments.

Artificial nano-and microcapsules that seek to mimic their natural counterparts can be constructed in different ways, leading to a variety of properties, as will be discussed in this review. [6][7][8] Enzymatic conversions can take place in the lumen of such capsules, and their membranes can be used to confine and tune reaction pathways. Synthetic capsules are also attracting a lot of attention because of their promising applications in the controlled release of pharmaceuticals. Capsules that bear recognition elements have been targeted to specific tissues or organs, providing a desirable vehicle for the aforementioned release of drugs. 9 For a chemist, the successful exploitation of capsules begins with their tailormade design and synthesis, for which cells and their organelles are the primary source of inspiration. In order to be able to do so, one needs insight into the design principles of nature to endow function to a molecule and to direct its self-assembly to a preset architecture. Although spectacular progresshasbeenmadeinthefieldofbioinspiredself-assembly, [10][11][12][13] unfortunately, the construction of an artificial cell is still not much more than a fantasy. Fortunately, more simple systems such as micelles, vesicles, and other assemblies of molecules may already partly solve the problem by providing a capsule that can be geared toward a desired application, e.g. the controlled release of drugs, as was demonstrated in the literature already quite a long time ago. [14][15][16] The view of life as being the result of a nanoscale phenomenon 17 is of more recent date and should rouse the interest in capsules for any chemist. Stijn F. M. van Dongen (group, center) was born in Goirle, The Netherlands, and studied chemistry at the Radboud University Nijmegen. He received his master's degree in 2006 after traineeships in the physical organic chemistry group of Prof. R. J. M. Nolte and the synthetic biology group of Prof. D. M. Hilvert at the ETH in Zu ¨rich, Switzerland. He is currently a Ph.D. student in the group of Profs.' R. J. M. Nolte and J. C. M. van Hest, working on the exploration of polymersomes as nanoreactors in a biological setting. Hans-Peter M. de Hoog (group, second from left) was born in Arnhem, The Netherlands, and graduated in chemistry at Utrecht University in 1998, specializing in the analysis of complex biomolecules. After a short stay at The Netherlands Organisation for Applied Scientific Research (TNO), he moved to the Radboud University Nijmegen in 2005 to pursue a Ph.D. in supramolecular and physical organic chemistry in the group of Prof. R. J. M. Nolte and J. J. L. M. Cornelissen. His research involves a collaborative project with Delft University of Technology (Prof. I. W. C. E. Arends) on the applicationdriven encapsulation of enzymes in polymersomes. Ruud J. R. W. Peters (group, right) obtained his bachelor's degree in molecular life sciences at the Radboud University Nijmegen in 2008. He is currently performing his master's research on the interactions between polymersomes a...

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Enzyme-filled polystyrene-b-poly(3-(isocyano-lalanyl-aminoethyl)thiophene) (PS-b-PIAT) nanoreactors are encapsulated together with free enzymes and substrates in a larger polybutadiene-b-poly(ethylene oxide) (PB-b-PEO) polymersome, forming a multicompartmentalized structure, which shows structural resemblance to the cell and its organelles. An original cofactor-dependent three-enzyme cascade reaction is performed, using either compatible or incompatible enzymes, which takes place across multiple compartments.

Progress in understanding signal transduction and metabolic pathways is hampered by a shortage of suitable sensors for tracking metabolites, second messengers, and neurotransmitters in living cells. Here we introduce a class of rationally designed semisynthetic fluorescent sensor proteins, called Snifits, for measuring metabolite concentrations on the cell surface of mammalian cells. Functional Snifits are assembled on living cells through two selective chemical labeling reactions of a genetically encoded protein scaffold. Our best Snifit displayed fluorescence intensity ratio changes on living cells significantly higher than any previously reported cell-surface-targeted fluorescent sensor protein. This work establishes a generally applicable and rational strategy for the generation of cell-surface-targeted fluorescent sensor proteins for metabolites of interest.