Continuous Transformation from Membrane-less Coacervates to Membranized Coacervates and Giant Vesicles: toward Multicompartmental Protocells with Complex (Membrane) Architectures.

The membranization of membrane-less coacervates paves the way for the exploitation of complex protocells with regard to structural and cell-like functional behaviors. However, the controlled transformation from membranized coacervates to vesicles remains a challenge. This can provide stable (multi)phase and (multi)compartmental architectures through the reconfiguration of coacervate droplets in the presence of (bioactive) polymers, bio(macro)molecules and/or nanoobjects. Herein, we present a continuous protocell transformation from membrane-less coacervates to membranized coacervates and, ultimately, to giant hybrid vesicles. This transformation process is orchestrated by altering the balance of non-covalent interactions through varying concentrations of an anionic terpolymer, leading to dynamic processes such as spontaneous membranization of terpolymer nanoparticles at the coacervate surface, disassembly of the coacervate phase mediated by the excess anionic charge, and the redistribution of coacervate components in membrane. The diverse protocells during the transformation course provide distinct structural features and molecular permeability. Notably, the introduction of multiphase coacervates in this continuous transformation process signifies advancements toward the creation of synthetic cells with different diffusible compartments. Our findings emphasize the highly controlled continuous structural reorganization of coacervate protocells and represents a novel step toward the development of advanced and sophisticated synthetic protocells with more precise compositions and complex (membrane) structures.

Protocells Capable of Generating a Cytoskeleton-like Structure from intracellular Membrane-active Artificial Organelles.

The intricate nature of eukaryotic cells with differently viscous intracellular compartments provides (membrane-active) enzymes to trigger time- and concentration-dependent processes in the intra-/extracellular matrix. Herein, we capitalize on membrane-active artificial organelles (AOs) to develop fluidic and stable proteinaceous membrane-based protocells. AOs in protocells induce the self-assembly of oligopeptides into an artificial cytoskeleton that underline their influence on the structure and functionality of protocells. A series of microscopical tools is used to validate the intracellular assembly and distribution of cytoskeleton, the changing protocells morphology, and AOs inclusion within cytoskeletal growth. Thus, the dynamics, diffusion and viscosity of intracellular components in the presence of cytoskeleton are evaluated by fluorescence tools and enzymatic assay. Membrane-active alkaline phosphatase in polymersomes as AOs fulfills the requirements of biomimetic eukaryotic cells to trigger intracellular environment, mobility, viscosity, diffusion and enzymatic activity itself as well as high mechanical stability and high membrane fluidity of protocells. Thus membrane-active AOs in protocells thoroughly provide a variable reaction space in a changing intracellular environment and underline their regulatory role in the fabrication of complex protocell architectures and functions. This study demonstrates an important contribution to effective biomimicry of cell-like structures, shapes and functions.

Biomimetic Cell Structures: Probing Induced pH-Feedback Loops and pH Self-Monitoring in Cytosol Using Binary Enzyme-Loaded Polymersomes in Proteinosome.

Structures and functions of eukaryotic cells with an outer permeable membrane, a cytoskeleton, functional organelles, and motility can be mimicked by giant multicompartment protocells containing various synthetic organelles. Herein, two kinds of artificial organelles with stimuli-triggered regulation ability, glucose oxidase-(GOx)-loaded pH-responsive polymersomes A (GOx-Psomes A) and urease-loaded pH-responsive polymersomes B (Urease-Psomes B), and a pH-sensor (Dextran-FITC) are encapsulated into proteinosomes via the Pickering emulsion method. Thus, a polymersomes-in-proteinosome system is constructed which is able to probe biomimetic pH homeostasis. Alternating fuels (glucose or urea) introduced from outside the protocell penetrate the membrane of proteinosomes and enter into GOx-Psomes A and Urease-Psomes B to produce chemical signals (gluconic acid or ammonia) resulting in pH-feedback loops (pH jump and pH drop). This will counteract the catalytic "switch on" or "switch off" of enzyme-loaded Psomes A and B owing to their different pH-responsive membranes. Dextran-FITC in the proteinosome allows self-monitoring of slight pH fluctuations in the lumen of protocells. Overall, this approach shows heterogeneous polymersome-in-proteinosome architectures with sophisticated features such as input-regulated pH changes mediated by negative and positive feedback in loops and cytosolic pH self-monitoring, features that are imperative for advanced protocell design.

Advancing Antiamyloidogenic Activity by Fine-Tuning Macromolecular Topology.

Amyloid ß peptide can aggregate into thin ß-sheet fibrils or plaques deposited on the extracellular matrix, which is the hallmark of Alzheimer's disease. Multifunctional macromolecular structures play an important role in inhibiting the aggregate formation of amyloidogenic materials and thus are promising candidates with antiamyloidogenic characteristics for the development of next-generation therapeutics. In this study, we evaluate how small differences in the dendritic topology of these structures influence their antiamyloidogenic activity by the comparison of "perfectly dendritic" and "pseudodendritic" macromolecules, both decorated with mannose units. Their compactness, the position of surface units, and the size of glyco-architectures influence their antiamyloidogenic activity against Aß 40, a major component of amyloid plaques. For the advanced analysis of the aggregation of the Aß peptide, we introduce asymmetric flow field flow fractionation as a suitable method for the quantification of large and delicate structures. This alternative method focuses on the quantification of complex aggregates of Aß 40 and glycodendrimer/glyco-pseudodendrimer over different time intervals of incubation, showing a good correlation to ThT assay and CD spectroscopy results. Kinetic studies of the second-generation glyco-pseudodendrimer revealed maximum inhibition of Aß 40 aggregates, verified with atomic force microscopy. The second-generation glyco-pseudodendrimer shows the best antiamyloidogenic properties confirming that macromolecular conformation in combination with optimal functional group distribution is the key to its performance. These molecular properties were validated and confirmed by molecular dynamics simulation.

Construction of Membraneless and Multicompartmentalized Coacervate Protocells Controlling a Cell Metabolism-like Cascade Reaction.

In recent years, there has been growing attention to designing synthetic protocells, capable of mimicking micrometric and multicompartmental structures and highly complex physicochemical and biological processes with spatiotemporal control. Controlling metabolism-like cascade reactions in coacervate protocells is still challenging since signal transduction has to be involved in sequential and parallelized actions mediated by a pH change. Herein, we report the hierarchical construction of membraneless and multicompartmentalized protocells composed of (i) a cytosol-like scaffold based on complex coacervate droplets stable under flow conditions, (ii) enzyme-active artificial organelles and a substrate nanoreservoir capable of triggering a cascade reaction between them in response to a pH increase, and (iii) a signal transduction component based on the urease enzyme capable of the conversion of an exogenous biological fuel (urea) into an endogenous signal (ammonia and pH increase). Overall, this strategy allows a synergistic communication between their components within the membraneless and multicompartment protocells and, thus, metabolism-like enzymatic cascade reactions. This signal communication is transmitted through a scaffold protocell from an "inactive state" (nonfluorescent protocell) to an "active state" (fluorescent protocell capable of consuming stored metabolites).

Crosslinked and Multi-Responsive Polymeric Vesicles as a Platform to Study Enzyme-Mediated Undocking Behavior: Toward Future Artificial Organelle Communication.

Various cellular functions are successfully mimicked, opening the door to the next generation of therapeutic approaches and systems biology. Herein, the first steps are taken toward the construction of artificial organelles for mimicking cell communication by docking and undocking of cargo in the membrane of swollen artificial organelles. Stimuli-responsive and crosslinked polymeric vesicles are used to allow docking processes at acidic pH at which ferrocene units in the swollen membrane state can undergo desired specific host-guest interaction using ß-cyclodextrin as model cargo. The release of the cargo mediated by two different enzymes, glucose oxidase and α-amylase, is investigated, triggered by distinct enzymatic undocking mechanisms. Different release times for a useful transport are shown that can be adapted to different communication pathways. In addition, Förster resonance energy transfer (FRET) experiments further support the hypotheses of host-guest inclusion complexation formation and their time-dependent breakdown. This work paves a way to a platform based on polymeric vesicles for synthetic biology, cell functions mimicking, and the construction of multifunctional cargo delivery system.

Reversible Molecular Capture and Release in Microfluidics by Host-Guest Interactions in Hydrogel Microdots.

The integration of microscopic hydrogels with high specific surface area and physically reactive groups into microfluidic systems for selective molecular interactions is attracting increasing attention. Herein, the reversible capture and release of molecules through host-guest interactions of hydrogel dots in a microfluidic device is reported, which translates the supramolecular chemistry to the microscale conditions under continuous flow. Polyacrylamide (PAAm) hydrogel arrays with grafted ß-cyclodextrin (ß-CD)  modified poly(2-methyl-2-oxazoline) (CD-PMOXA) chains are fabricated by photopolymerization and integrated into a polydimethylsiloxane (PDMS)-on-glass chip. The ß-CD/adamantane (ß-CD/Ada) host-guest complex is confirmed by two dimensional Nuclear Overhauser Effect Spectroscopy NMR (2D NOESY NMR) prior to transfer to microfluidics. Ada-modified molecules are successfully captured by host-guest interaction formed between the CD-PMOXA grafted chains in the hydrogel network and the guest molecule in the solution. Furthermore, the captured molecules are released by perfusing free ß-CD with higher binding affinity than those grafted in the hydrogel array. A small guest molecule adamantane-fluorescein-isothiocyanate (Ada-FITC) and a macromolecular guest molecule (Ada-PMOXA-Cyanine 5 (Cy5)) are separately captured and released for three times with a release ratio up to 46% and 92%, respectively. The reproducible capture and release of functional molecules with different sizes demonstrates the stability of this hydrogel system in microfluidics and will provide an opportunity for future applications.

Probing Crowdedness of Artificial Organelles by Clustering Polymersomes for Spatially Controlled and pH-Triggered Enzymatic Reactions.

Most sophisticated biological functions and features of cells are based on self-organization, and the coordination and connection between their cell organelles determines their key functions. Therefore, spatially ordered and controllable self-assembly of polymersomes to construct clusters to simulate complex intracellular biological functions has attracted widespread attention. Here, we present a simple one-step copper-free click strategy to cross-link nanoscale pH-responsive and photo-cross-linked polymersomes (less than 100 nm) to micron-level clusters (more than 90% in 0.5-2 µm range). Various influencing factors in the clustering process and subsequent purification methods were studied to obtain optimal clustered polymeric vesicles. Even when polymeric vesicles separately loaded with different enzymes (glucose oxidase and myoglobin) are coclustered, the overall permeability of the clusters can still be regulated through tuning the pH values on demand. Compared with simple blending of those enzyme-loaded polymersomes, the rate of enzymatic cascade reaction increased significantly due to the interconnected complex microstructure established. The connection of catalytic nanocompartments into clusters confining different enzymes of a cascade reaction provides an excellent platform for the development of artificial systems mimicking natural organelles or cells.

Redox- and pH-Responsive Polymersomes with Ferrocene Moieties Exhibiting Peroxidase-like, Chemoenzymatic Activity and H2O2-Responsive Release Behavior.

The development of compartments for the design of cascade reactions in a local space requires a selective spatiotemporal control. The combination of enzyme-loaded polymersomes with enzymelike units shows a great potential in further refining the diffusion barrier and the type of reactions in nanoreactors. Herein, pH-responsive and ferrocene-containing block copolymers were synthesized to realize pH-stable and multiresponsive polymersomes. Permeable membrane, peroxidase-like behavior induced by the redox-responsive ferrocene moieties and release properties were validated using cyclovoltammetry, dye TMB assay, and rupture of host-guest interactions with ß-cyclodextrin, respectively. Due to the incorporation of different block copolymers, the membrane permeability of glucose oxidase-loaded polymersomes was changed by increasing extracellular glucose concentration and in TMB assay, allowing for the chemoenzymatic cascade reaction. This study presents a potent synthetic, multiresponsive nanoreactor platform with tunable (e.g., redox-responsive) membrane properties for potential application in therapeutics.

Neurotoxicity of poly(propylene imine) glycodendrimers.

Published results of studies on poly(propylene imine) (PPI) dendrimers indicate their potential use in the treatment of brain cancer or neurodegenerative diseases due to their ability to cross the blood-brain barrier. However, depending on dose, neurotoxicity may occur. Here, we discuss the impact of maltotriose modified PPI dendrimers on rat's nervous system. Wistar rats were treated intravenously for 14 consecutive days with densely (dense-shell; DS) and partly (open-shell; OS) modified PPI dendrimers at doses established as safe in the previous experiment following a single DS or OS administration. The examination included an estimation of the motility and the clinical symptoms of the respiratory, nervous, and cardiovascular systems. Both DS and OS glycodendrimers (GDs) induced adverse effects at the doses tested. Multiple administrations of PPI-OS had a detrimental influence on rats' survival. These findings suggest that the dendrimers adversely influence the nervous system and their toxic effects accumulate over time. In PPI-DS treated animals, the harmful effects were less severe but still present. However, with each treatment day, the clinical symptoms in both groups were less severe as if the animals developed tolerance to GDs. We hypothesize that the neurotoxicity of tested dendrimers is related to nanoparticles-induced autophagy.

Construction of Eukaryotic Cell Biomimetics: Hierarchical Polymersomes-in-Proteinosome Multicompartment with Enzymatic Reactions Modulated Protein Transportation.

The eukaryotic cell is a smart compartment containing an outer permeable membrane, a cytoskeleton, and functional organelles, presenting part structures for life. The integration of membrane-containing artificial organelles (=polymersomes) into a large microcompartment is a key step towards the establishment of exquisite cellular biomimetics with different membrane properties. Herein, an efficient way to construct a hierarchical multicompartment composed of a hydrogel-filled proteinosome hybrid structure with an outer homogeneous membrane, a smart cytoskeleton-like scaffold, and polymersomes is designed. Specially, this hybrid structure creates a micro-environment for pH-responsive polymersomes to execute a desired substance transport upon response to biological stimuli. Within the dynamic pH-stable skeleton of the protein hydrogels, polymersomes with loaded PEGylated insulin biomacromolecules demonstrate a pH-responsive reversible swelling-deswelling and a desirable, on-demand cargo release which is induced by the enzymatic oxidation of glucose to gluconic acid. This stimulus responsive behavior is realized by tunable on/off states through protonation of the polymersomes membrane under the enzymatic reaction of glucose oxidase, integrated in the skeleton of protein hydrogels. The integration of polymersomes-based hybrid structure into the proteinosome compartment and the stimuli-response on enzyme reactions fulfills the requirements of eukaryotic cell biomimetics in complex architectures and allows mimicking cellular transportation processes.

Nanoparticles for Directed Immunomodulation: Mannose-Functionalized Glycodendrimers Induce Interleukin-8 in Myeloid Cell Lines.

New therapeutic strategies for personalized medicine need to involve innovative pharmaceutical tools, for example, modular nanoparticles designed for direct immunomodulatory properties. We synthesized mannose-functionalized poly(propyleneimine) glycodendrimers with a novel architecture, where freely accessible mannose moieties are presented on poly(ethylene glycol)-based linkers embedded within an open-shell maltose coating. This design enhanced glycodendrimer bioactivity and led to complex functional effects in myeloid cells, with specific induction of interleukin-8 expression by mannose glycodendrimers detected in HL-60 and THP-1 cells. We concentrated on explaining the molecular mechanism of this phenomenon, which turned out to be different in both investigated cell lines: in HL-60 cells, transcriptional activation via AP-1 binding to the promoter predominated, while in THP-1 cells (which initially expressed less IL-8), induction was mediated mainly by mRNA stabilization. The success of directed immunomodulation, with synthetic design guided by assumptions about mannose-modified dendrimers as exogenous regulators of pro-inflammatory chemokine levels, opens new possibilities for designing bioactive nanoparticles.

Long-Term Retarded Release for the Proteasome Inhibitor Bortezomib through Temperature-Sensitive Dendritic Glycopolymers as Drug Delivery System from Calcium Phosphate Bone Cement.

For the local treatment of bone defects, highly adaptable macromolecular architectures are still required as drug delivery system (DDS) in solid bone substitute materials. Novel DDS fabricated by host-guest interactions between ß-cyclodextrin-modified dendritic glycopolymers and adamantane-modified temperature-sensitive polymers for the proteasome inhibitor bortezomib (BZM) is presented. These DDS induce a short- and long-term (up to two weeks) retarded release of BZM from calcium phosphate bone cement (CPC) in comparison to a burst release of the drug alone. Different release parameters of BZM/DDS/CPC are evaluated in phosphate buffer at 37 °C to further improve the long-term retarded release of BZM. This is achieved by increasing the amount of drug (50-100 µg) and/or DDS (100-400 µg) versus CPC (1 g), by adapting the complexes better to the porous bone cement environment, and by applying molar ratios of excess BZM toward DDS with 1:10, 1:25, and 1:100. The temperature-sensitive polymer shells of BZM/DDS complexes in CPC, which allow drug loading at room temperature but are collapsed at body temperature, support the retarding long-term release of BZM from DDS/CPC. Thus, the concept of temperature-sensitive DDS for BZM/DDS complexes in CPC works and matches key points for a local therapy of osteolytic bone lesions.

Light-Driven Proton Transfer for Cyclic and Temporal Switching of Enzymatic Nanoreactors.

Temporal activation of biological processes by visible light and subsequent return to an inactive state in the absence of light is an essential characteristic of photoreceptor cells. Inspired by these phenomena, light-responsive materials are very attractive due to the high spatiotemporal control of light irradiation, with light being able to precisely orchestrate processes repeatedly over many cycles. Herein, it is reported that light-driven proton transfer triggered by a merocyanine-based photoacid can be used to modulate the permeability of pH-responsive polymersomes through cyclic, temporally controlled protonation and deprotonation of the polymersome membrane. The membranes can undergo repeated light-driven swelling-contraction cycles without losing functional effectiveness. When applied to enzyme loaded-nanoreactors, this membrane responsiveness is used for the reversible control of enzymatic reactions. This combination of the merocyanine-based photoacid and pH-switchable nanoreactors results in rapidly responding and versatile supramolecular systems successfully used to switch enzymatic reactions ON and OFF on demand.

Maltotriose-modified poly(propylene imine) Glycodendrimers as a potential novel platform in the treatment of chronic lymphocytic Leukemia. A proof-of-concept pilot study in the animal model of CLL.

Cancer nanotherapeutics have shown promise in resolving some of the limitations of conventional drug delivery systems such as nonspecific biodistribution and targeting, lack of water solubility, and low therapeutic indices, Among the various nanoparticles that are available, dendrimers, highly branched macromolecules with a specific size and shape, are one of the most promising ones. In this preliminary study, we tested the anti-tumor activity of maltotriose-modified fourth-generation poly(propylene imine) glycodendrimers (PPI-G4-M3) in vivo in the subcutaneous MEC-1 xenograft model of human chronic lymphocytic leukemia (CLL) in NOD scid gamma mice. Fludarabine was used for model validation and as a positive treatment control. The anti-tumor response was calculated as tumor volume, tumor control ratio, and tumor growth inhibition. The study showed that PPI-G4-M3 inhibited subcutaneous tumor growth more efficiently than fludarabine. The anti-tumor response was dose-dependent. Cationic PPI-G4-M3 showed the highest anti-tumor activity but also higher toxicity than the neutral dendrimers and fludarabine. These first promising results warrant further studies in the optimization of dendrimers charge, dose, route and schedule of administration to combat CLL.

DOTA Glycodendrimers as Cu(II) Complexing Agents and Their Dynamic Interaction Characteristics toward Liposomes.

Copper (Cu)(II) ions, mainly an excess amount, play a negative role in the course of several diseases, like cancers, neurodegenerative diseases, and the so-called Wilson disease. On the contrary, Cu(II) ions are also capable of improving anticancer drug efficiency. For this reason, it is of great interest to study the interacting ability of Cu(II)-nanodrug and Cu(II)-nanocarrier complexes with cell membranes for their potential use as nanotherapeutics. In this study, the complex interaction between 1,4,7,10-tetraazacyclododecan-N,N',N'',N'''-tetraacetic acid (DOTA)-functionalized poly(propyleneimine) (PPI) glycodendrimers and Cu(II) ions and/or neutral and anionic lipid membrane models using different liposomes is described. These interactions were investigated via dynamic light scattering (DLS), ζ-potential (ZP), electron paramagnetic resonance (EPR), fluorescence anisotropy, and cryogenic transmission electron microscopy (cryo-TEM). Structural and dynamic information about the PPI glycodendrimer and its Cu(II) complexes toward liposomes was obtained via EPR. At the binding site Cu-N2O2 coordination prevails, while at the external interface, this coordination partially weakens due to competitive dendrimer-liposome interactions, with only small liposome structural perturbation. Fluorescence anisotropy was used to evaluate the membrane fluidity of both the hydrophobic and hydrophilic parts of the lipid bilayer, while DLS and ZP allowed us to determine the distribution profile of the nanoparticle (PPI glycodendrimer and liposomes) size and surface charge, respectively. From this multitechnique approach, it is deduced that DOTA-PPI glycodendrimers selectively extract Cu(II) ions from the bioenvironment, while these complexes interact with the liposome surface, preferentially with even more negatively charged liposomes. However, these complexes are not able to cross the cell membrane model and poorly perturb the membrane structure, showing their potential for biomedical use.

Avidin Localizations in pH-Responsive Polymersomes for Probing the Docking of Biotinylated (Macro)molecules in the Membrane and Lumen.

To mimic organelles and cells and to construct next-generation therapeutics, asymmetric functionalization and location of proteins for artificial vesicles is thoroughly needed to emphasize the complex interplay of biological units and systems through spatially separated and spatiotemporal controlled actions, release, and communications. For the challenge of vesicle (= polymersome) construction, the membrane permeability and the location of the cargo are important key characteristics that determine their potential applications. Herein, an in situ and post loading process of avidin in pH-responsive and photo-cross-linked polymersomes is developed and characterized. First, loading efficiency, main location (inside, lumen, outside), and release of avidin under different conditions have been validated, including the pH-stable presence of avidin in polymersomes' membrane outside and inside. This advantageous approach allows us to selectively functionalize the outer and inner membranes as well as the lumen with several bio(macro)molecules, generally suited for the construction of asymmetrically functionalized artificial organelles. In addition, a fluorescence resonance energy transfer (FRET) effect was used to study the permeability or uptake of the polymersome membrane against a broad range of biotinylated (macro)molecules (different typology, sizes, and shapes) under different conditions.

Bivalent Peptide- and Chelator-Containing Bioconjugates as Toolbox Components for Personalized Nanomedicine.

While personalized therapy bears an enormous potential in cancer therapy, the development of flexible, tailorable delivery systems remains challenging. Here, we present a "tool-kit" of various avidin-based bioconjugates (BCs) for the preparation of personalized delivery systems. Corresponding BCs were synthesized using the self-assembly of avidin with various biotinylated ligands, such as one cationic glycodendrimer for dendriplex adsorption and two functional ligands for imaging (glycodendrimers with DOTA or NOTA units) or targeting (biotinylated PEG decorated with ligands). Substituting antibodies for targeting small molecules were coupled to biotin-PEG compounds for addressing the folate receptor (FR), epidermal growth factor receptor (EGFR), and prostate-specific membrane antigen (PSMA). After successful characterization and proof of good storage and redispersion properties of BCs, cytotoxicity assays and first in vivo imaging studies with 99mTc-complexing bioconjugates provide evidence that these BCs and their avidin analogues can be used as tool-kit components in theranostic systems for personalized medicine.

Double cross-linked supramolecular hydrogels with tunable properties based on host-guest interactions.

We report a novel double cross-linked hydrogel system based on polyacrylamide and poly(2-methyl-2-oxazoline) (PMOXA) network chains, as well as on supramolecular host-guest interactions with on-demand tailored mechanical properties. Well-defined vinyl-bearing PMOXA macromonomers, functionalized with either ß-cyclodextrin units (ß-CD-PMOXA) or adamantane units (Ada-PMOXA), were synthesized and confirmed using 1H NMR, MALDI-TOF-MS and GPC measurements. The complexation between adamantane and ß-CD modified macromonomers in solution towards bismacromonomers was confirmed by 2D NOESY NMR and DLS. After introducing these bismacromonomers into the polyacrylamide hydrogel, the supramolecular non-covalent Ada/ß-CD bond was responsible for the presence of PMOXA network chains to form a dense network. Once the interactions broke, the PMOXA chains no longer contributed to the network, but became dangling graft side chains in a predominated polyacrylamide network. Their dissociative nature influenced the physical properties, including the swelling behavior and mechanics of the final hydrogel. Rheological experiments proved that the E-modulus of the network was significantly increased by the supramolecular host-guest interactions. Tuning the lengths of PMOXA network chains even allowed the modification of the changes in mechanical strength, also through the addition of free ß-CD. The tunable properties of the double cross-linked supramolecular hydrogel proved their unique strength for future applications.

Control of Nanoparticle Release by Membrane Composition for Dual-Responsive Nanocapsules.

Stimulus-responsive polymeric nanocapsules usable as cell mimics can be engineered to precisely control cargo release. This work reports the release behavior of post-loaded nanoparticles through permeable membranes of stable pH and temperature dual-responsive polymeric nanocapsules (CP1, CP2, and CP3) with the same membrane thickness but different membrane composition, prepared by layer-by-layer assembly and surface-initiated single electron transfer living radical polymerization, respectively. These nanocapsules differ in their tunable membrane permeability for post-loaded nanoparticles as protein mimics, tailored by pH and temperature stimuli. Release mechanisms are dominated by membrane composition, such as polyelectrolyte multilayer membrane for CP1, pure cationic membrane for CP2, and valve-like functions for CP3. Thus, one can postulate the main locations of post-loaded protein mimics in the different nanocapsules. Understanding the post-loading and diffusion mechanism of nanoparticles through permeable membranes in cell mimics paves the way for the construction of new "smart" synthetic protocells with control over the exchange of bioactive nanoparticles between different compartments.