Understanding the diffusion of nanoparticles through permeable membranes in cell mimics paves the way for the construction of more sophisticated synthetic protocells with control over the exchange of nanoparticles or biomacromolecules between different compartments. Nanoparticles postloading by swollen pH switchable polymersomes is investigated and nanoparticles locations at or within polymersome membrane and polymersome lumen are precisely determined. Validation of transmembrane diffusion properties is performed based on nanoparticles of different origin—gold, glycopolymer protein mimics, and the enzymes myoglobin and esterase—with dimensions between 5 and 15 nm. This process is compared with the in situ loading of nanoparticles during polymersome formation and analyzed by advanced multiple‐detector asymmetrical flow field‐flow fractionation (AF4). These experiments are supported by complementary i) release studies of protein mimics from polymersomes, ii) stability and cyclic pH switches test for in polymersome encapsulated myoglobin, and iii) cryogenic transmission electron microscopy studies on nanoparticles loaded polymersomes. Different locations (e.g., membrane and/or lumen) are identified for the uptake of each protein. The protein locations are extracted from the increasing scaling parameters and the decreasing apparent density of enzyme‐containing polymersomes as determined by AF4. Postloading demonstrates to be a valuable tool for the implementation of cell‐like functions in polymersomes.

Robust, multiresponsive, and multifunctional nanovesicles are in high demand not only as carrier systems but also for applications in microsystem devices and nanotechnology. Hence, multifunctional, pH-responsive, and photo-cross-linked polymersomes decorated with adamantane and azide groups are prepared by mixed selfassembly of suitably end-modified block copolymers and are used for the subsequent postconjugation of the polymersome surface by using covalent and noncovalent approaches. For the covalent approach, nitroveratryloxycarbonyl-protected amine (NVOC) molecules as lightresponsive moieties are introduced into the polymersomes through an azide−alkyne click reaction. After photocleavage of NVOC units, functional dye molecules react with the now freely accessible amine groups. The noncovalent approach is performed subsequently to introduce further moieties, making use of the strong adamantane-β-cyclodextrin host−guest interactions. It is quantitatively proven that all reactive groups have sufficient accessibility as well selective and orthogonal reactivity throughout these stepwise processes to allow the successful establishment of aimed pH-and light-responsive multifunctional polymersomes. Moreover, this sequential methodology is also applied to obtain doxorubicin-loaded multifunctional polymersomes for an efficient pH-controlled drug release. Overall, tunable membrane permeability combined with the potential for introducing multiple targeting groups by light-exposure or host−guest interactions make these smart polymersomes promising nanocontainers for many applications.

embracing layer-by-layer assembly (LBL) methods, [4][5][6] and iii) self-assembly of the amphiphilic block copolymers. [7][8][9] In principle, the formation of the polymer shell that covers the core space is triggered by either covalent or non-covalent bonding depending on the selected method. The heterophase polymerization systems consist of (mini)emulsions and suspensions resulting in the covalently linked polymers covering the core-forming droplets. On the other hand, the miniemulsion technology also provides the opportunity to make capsules from preformed polymers when the polymerization cannot be performed in heterophase systems as shown by Landfester et al. [10][11][12] Miniemulsion polymerization is understood as a polymerization technique where stable droplets are formed prior to polymerization and the droplets are then polymerized. LBL approaches are commonly used in combination with templating methods. The principle is to use an organic or inorganic particle as a support in which the polymers are either adsorbed or grown by surface initiated polymerization (SIP) techniques on the surface of the particle template. [13] In this approach, different types and sized particles made of gold, silica, and carbonate are utilized as platforms. The template particles are further removed through etching procedures such as dissolution in acids to produce hollow capsules having a polymer shell. [6] Another promising way of polymeric nanocapsule formation is to use the self-assembly of specially designed amphiphilic block copolymers in water which in turn leads to polymersomes comprising a bilayer membrane and an aqueous core. [7] These vesicular structures are artificial mimetics of the liposomes that are self-assembled from natural phospholipids. Polymersomes showed various outstanding properties over their lipid counterparts such as higher mechanical strength, enhanced stability as well as a wide range of chemical versatility that enhances application opportunities in nanomedicine. [14,15] Several excellent reviews about polymeric nanocapsules focusing on their synthesis through miniemulsion processes, [1][2][3]16,17] templating approaches including layer-by-layer assemblies [4][5][6]18] as well as self-assembly processes [8,14,[19][20][21][22][23] have been published. Generally, their use in biomedical science including drug delivery and synthetic biology is underlined. However, there are relatively few examples of comparative reviews [13,[24][25][26][27][28][29] to emphasize the application-oriented eligibilities of the polymeric nanocapsules formed by different methods. In this context, we aim to discuss from a modular perspective both self-assembled nanocapsules, so-called polymersomes, and nanocapsules with a covalently formed shell, mainly obtained by the miniemulsion technique (Figure 1). NanocapsulesThe formation of nanocapsules from a modular perspective for self-assembled nanocapsules, so-called polymersomes, and nanocapsules with a covalently formed shell are discussed in this review. It is shown that the...

Increasing complexity and diversity of polymersomes and their compartments is a key issue for mimicking cellular functions and protocells. Thus, new challenges arise in terms of achieving tunable membrane permeability and combining it with control over the membrane diffusion process, and thus enabling a localized and dynamic control of functionality and docking possibilities within or on the surface of polymeric compartments. This study reports the concept of polymersomes with pH-tunable membrane permeability for controlling sequential docking and undocking processes of small molecules and nanometer-sized protein mimics selectively on the inside and outside of the polymersome membrane as a further step toward the design of intelligent multifunctional compartments for use in synthetic biology and as protocells. Host-guest interactions between adamantane and β-cyclodextrin as well as noncovalent interactions between poly(ethylene glycol) tails and β-cyclodextrin are used to achieve selective and dynamic functionalization of the inner and outer spheres of the polymersome membrane.