M. Nijemeisland, L. K. E. A. Abdelmohsen, W.T.S. Huck, D.A. Wilson, J.C.M. van Hest A Compartmentalized Out-of-Equilibrium Enzymatic Reaction Network for Sustained Autonomous Movement. ACS Central Science 2016, 2 (11), 843-849 DOI: 10.1021/acscentsci.6b00254
Every living cell is a compartmentalized out-of-equilibrium system exquisitely able to convert chemical energy into function. In order to maintain homeostasis, the flux of metabolites is tightly controlled by regulatory enzymatic networks. A crucial prerequisite for the development of lifelike materials is the construction of synthetic systems with compartmentalized reaction networks that maintain out-of-equilibrium function. Here, we aim for autonomous movement as an example of the conversion of feedstock molecules into function. The flux of the conversion is regulated by a rationally designed enzymatic reaction network with multiple feedforward loops. By compartmentalizing the network into bowl-shaped nanocapsules the output of the network is harvested as kinetic energy. The entire system shows sustained and tunable microscopic motion resulting from the conversion of multiple external substrates. The successful compartmentalization of an out-of-equilibrium reaction network is a major first step in harnessing the design principles of life for construction of adaptive and internally regulated lifelike systems.
R. S. M. Rikken, H. Engelkamp, R. J. M. Nolte, J. C. Maan, J. C. M. van Hest, D. A. Wilson, P. C. M. Christianen, Shaping polymersomes into predictable morphologies via out-of-equilibrium self-assembly. Nature Communications 2016, 7, 12606 DOI:10.1038/ncomms12606
Polymersomes are bilayer vesicles, self-assembled from amphiphilic block copolymers. They are versatile nanocapsules with adjustable properties, such as flexibility, permeability, size and functionality. However, so far no methodological approach to control their shape exists. Here we demonstrate a mechanistically fully understood procedure to precisely control polymersome shape via an out-of-equilibrium process. Carefully selecting osmotic pressure and permeability initiates controlled deflation, resulting in transient capsule shapes, followed by reinflation of the polymersomes. The shape transformation towards stomatocytes, bowl-shaped vesicles, was probed with magnetic birefringence, permitting us to stop the process at any intermediate shape in the phase diagram. Quantitative electron microscopy analysis of the different morphologies reveals that this shape transformation proceeds via a long-predicted hysteretic deflation–inflation trajectory, which can be understood in terms of bending energy. Because of the high degree of controllability and predictability, this study provides the design rules for accessing polymersomes with all possible different shapes.
Formation of Well-Defined, Functional Nanotubes via Osmotically Induced Shape Transformation of Biodegradable Polymersomes
. L. K. E. A. Abdelmohsen, D. S. Williams, J. Pille, S. G. Ozel, R. S. M. Rikken, D. A.Wilson, J. C. M. van Hest, Formation of Well-Defined, Functional Nanotubes via Osmotically Induced Shape Transformation of Biodegradable Polymersomes. Journal of the American Chemical Society 2016, 138 (30), 9353-6 DOI:10.1021/jacs.6b03984
Polymersomes are robust, versatile nanostructures that can be tailored by varying the chemical structure of copolymeric building blocks, giving control over their size, shape, surface chemistry, and membrane permeability. In particular, the generation of nonspherical nanostructures has attracted much attention recently, as it has been demonstrated that shape affects function in a biomedical context. Until now, nonspherical polymersomes have only been constructed from nondegradable building blocks, hampering a detailed investigation of shape effects in nanomedicine for this category of nanostructures. Herein, we demonstrate the spontaneous elongation of spherical polymersomes comprising the biodegradable copolymer poly(ethylene glycol)-b-poly(d,l-lactide) into well-defined nanotubes. The size of these tubes is osmotically controlled using dialysis, which makes them very easy to prepare. To confirm their utility for biomedical applications, we have demonstrated that, alongside drug loading, functional proteins can be tethered to the surface utilizing bio-orthogonal “click” chemistry. In this way the present findings establish a novel platform for the creation of biocompatible, high-aspect ratio nanoparticles for biomedical research.
R. J. R. W. Peters, M. Marguet, S. Marais, M. W. Fraaije, J. C. M. van Hest, S. Lecommandoux Cascade Reactions in Multicompartmentalized Polymersomes. Angewandte Chemie-International Edition 2014, 53, 146-150 DOI:10.1002/anie.201308141
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.
M. C. M. van Oers, F. P. J. T. Rutjes, J. C. M. van Hest Tubular Polymersomes: A Cross-Linker-Induced Shape Transformation. Journal Of The American Chemical Society 2013, 135, 16308-16311 DOI:10.1021/ja408754z
Polymersomes, polymeric vesicles constructed of block copolymers, can undergo a sphere-to-tubule transition under the influence of a chemical modification of the polymeric bilayer. A strain-promoted alkyne–azide cycloaddition (SPAAC) reaction between azide handles inside the hydrophobic domain of the membrane and an excess of a bicyclo[6.1.0]nonyne (BCN)-cross-linker causes the vesicle to stretch in one dimension. Tubular polymersomes up to 2 μm in length can be obtained with this shape transformation. The introduction of a cleavable cross-linker makes this process reversible and opens the way for future drug delivery applications.
Wilson D.A.; Nolte, R.J.M.; van Hest, J.C.M., Autonomous movement of platinum-loaded stomatocytes. Nature Chemistry 2012, 4, 268 DOI:10.1038/nchem.1281
Polymer stomatocytes are bowl-shaped structures of nanosize dimensions formed by the controlled deformation of polymer vesicles. The stable nanocavity and strict control of the opening are ideal for the physical entrapment of nanoparticles which, when catalytically active, can turn the stomatocyte morphology into a nanoreactor. Herein we report an approach to generate autonomous movement of the polymer stomatocytes by selectively entrapping catalytically active platinum nanoparticles within their nanocavities and subsequently using catalysis as a driving force for movement. Hydrogen peroxide is free to access the inner stomatocyte cavity, where it is decomposed by the active catalyst (the entrapped platinum nanoparticles) into oxygen and water. This generates a rapid discharge, which induces thrust and directional movement. The design of the platinum-loaded stomatocytes resembles a miniature monopropellant rocket engine, in which the controlled opening of the stomatocytes directs the expulsion of the decomposition products away from the reaction chamber (inner stomatocyte cavity).
van Eldijk, M. B.; Wang, J. C. Y.; Minten, I. J.; Li, C.; Zlotnick, A.; Nolte, R. J. M.; Cornelissen, J. J. L. M.; van Hest, J. C. M., Designing Two Self-Assembly Mechanisms into One Viral Capsid Protein. Journal Of The American Chemical Society 2012, 134 (45), 18506-18509 DOI:10.1021/ja308132z
ELP-CP, a structural fusion protein of the thermally responsive elastin-like polypeptide (ELP) and a viral capsid protein (CP), was designed, and its assembly properties were investigated. Interestingly, this protein-based block copolymer could be self-assembled via two mechanisms into two different, well-defined nanocapsules: (1) pH-induced assembly yielded 28 nm virus-like particles, and (2) ELP-induced assembly yielded 18 nm virus-like particles. The latter were a result of the emergent properties of the fusion protein. This work shows the feasibility of creating a self-assembly system with new properties by combining two structural protein elements.
van Dongen, S. F. M.; Verdurmen, W. P. R.; Peters, R.; Nolte, R. J. M.; Brock, R.; van Hest, J. C. M., Cellular Integration of an Enzyme-Loaded Polymersome Nanoreactor. Angewandte Chemie-International Edition 2010, 49 (40), 7213-7216 DOI:10.1002/anie.201002655
Cells with implants: Porous enzyme-loaded polymersomes were constructed that display the cell-penetrating peptide tat on their surfaces. These nanoreactors are taken up by mammalian cells through macropinocytosis. Inside the cells, the polymersomes are only partially routed to acidic compartments. Polymersomes with horseradish peroxidase as a model cargo enzyme displayed sustained intracellular activity.