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...

Multicompartmentalized polymersomes are formed using block co-polymers PMOXA-PDMS-PMOXA and PS-PIAT, and are subsequently proven to be capable of selective encapsulation of biomacromolecules. This architecture mimics the compartmentalization found in cells and may serve as a simple, albeit robust, model system.

Polystyrene-polyisocyanopeptide (PS-PIAT) polymersomes containing CALB in two different locations, one in the aqueous inner compartment and one in the bilayer, were investigated for enzymatic ring-opening polymerization of lactones in water. It is shown that the monomers 8-octanolactone and dodecalactone yield oligomers with this polymersome system. It is also observed that the polymerization activity is dependent on the position of the enzyme in the polymersome. SEM investigations show that the polymersome structures were destabilized during the polymerization. Further investigations show that the vesicular morphology of the polymersomes was destabilized only in the case of polymer product formation.

A multicompartment cascade reaction is presented in a polymersome-in-polymersome architecture, which is regulated by insertion of a channel protein in the inner compartment's polymer membrane.