Nanostructured, porous metals are of great interest for material scientists since they combine high surface area, gas permeability, electrical conductivity, plasmonic behavior, and size-enhanced catalytic reactivity. Here we present the formation of multimetallic porous three-dimensional networks by a template-free self-assembly process. Nanochains are formed by the controlled coalescence of Au, Ag, Pt, and Pd nanoparticles in aqueous media, and their interconnection and interpenetration leads to the formation of a self-supporting network. The resulting noble-metal-gels are transformed into solid aerogels by the supercritical drying technique. Compared to previously reported results, the technique is facilitated by exclusion of additional destabilizers. Moreover, temperature control is demonstrated as a powerful tool, allowing acceleration of the gelation process as well as improvement of its reproducibility and applicability. Electron microscopy shows the nanostructuring of the network and its high porosity. XRD and EDX STEM are used to investigate the alloying behavior of the bimetallic aerogels and prove the control of the alloying state by temperature induced phase modifications. Furthermore, the resulting multimetallic aerogels show an extremely low relative density (<0.2%) and a very high surface area (>50 m2/g) compared to porous noble metals obtained by other approaches. Electrically conductive thin films as well as hybrid materials with organic polymers are depicted to underline the processability of the materials, which is a key factor regarding handling of the fragile structures and integration into device architectures. Owing to their exceptional and tunable properties, multimetallic aerogels are very promising materials for applications in heterogeneous catalysis and electrocatalysis, hydrogen storage, and sensor systems but also in surface enhanced Raman spectroscopy (SERS) and the preparation of transparent conductive substrates.

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.

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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.

In the context of diligent efforts to improve the tumor targeting efficiency of drug carriers, a shape-persistent polymersome which possess a pH-tunable membrane as well as folate targeting antennae is reported. The membrane of such polymersomes behaves as gate which undergoes "on" and "off" switches in response to pH stimuli. Thus, polymersomes can effectively prohibit the premature release of chemotherapeutic agents such as doxorubicin in physiological conditions, but promote drug release once they are triggered in the acidified endosomal compartment. Importantly, the folate moieties are installed on the surface of polymersomes as protruding antennae by doping the polymersomes with folate-terminated block copolymers designed to have longer PEG segments. Thereby, the folate moieties are freed from concealment and steric effects exerted by the dense PEG corona. The cellular uptake of the FA-antennae polymersomes by tumor cells is significantly enhanced facilitated by the freely accessible folate antennae; however, the normal cells record a low level of cellular uptake due to the stealth property of the PEG corona. Overall, the excellent biocompatibility, controlled permeability, targeted internalization, as well as selective cytotoxicity of such polymersomes set up the basis for properly smart carrier for targeted drug delivery.