Vesicles Formed by Oligostyrene‐block‐Oligoaniline‐block‐Oligostyrene Triblock Oligomer

Novel π‐conjugated coil–rod–coil triblock oligomers containing optoelectronic active oligoaniline segments were synthesized. The block oligomer can self‐assemble into diverse aggregating morphologies including spherical micelles and thin‐layer vesicles in THF, which is found associated with the removing of the protecting groups of oligoaniline segments. A possible mechanism was proposed to explain the self‐assembly behavior changes in which chain conformation variation of the aniline segments initiated from deprotection of the nitrogen atoms is pointed to be the key factor that dominates the transition process.

     

A new track for antibacterial treatment: Progress and challenges of using cytomembrane-based vesicles to combat bacteria

The emergence and re-emergence of antibiotic-resistant bacteria, especially superbugs, are leading to complicated infections that are increasingly difficult to treat. Therefore, novel alternative antimicrobial therapies are urgently needed to reduce the morbidity and mortality caused by antibiotic resistance. The development of biomimetic-based therapy is expected to provide innovative means for addressing this challenging task. As a kind of novel biomaterial, cytomembrane-based vesicles (MVs) continue to receive considerable attention in antimicrobial therapy owing to their inherent biocompatibility, design flexibility, and remarkable ability to interact with biological molecules or the surrounding environment. These remarkable cell-like properties and their inherent interaction with pathogens, toxins, and the immune system underlie MVs-based functional protein therapy and targeted delivery to develop advanced therapeutic strategies against bacterial infection. This review provides a fundamental understanding of the characteristics and physiological functions of cytomembrane-based vesicles, focusing on their potential to combat bacterial infections, including detoxification, immune modulation, antibiotics delivery, and physical therapy. In addition, the future possibilities and remaining challenges for clinically implementing MVs in the field of antibacterial treatment are discussed.     

A Novel Type of Vesicles Based on Ionic and π–π Interactions

Electrostatic self‐assembly can be used to form supramolecular vesicles in aqueous solution. Vesicles consist of cationic G8 poly(amidoamine) dendrimers and the trivalent sulfonate dye Ar27. No classical amphiphiles are present but the interplay of electrostatics, π–π interaction and geometric factors influences the structure formation. Labeled guest molecules, both small molecules and peptides, can be included inside these vesicles and vesicles imaged by fluorescence techniques. The structure was studied by dynamic and static light scattering, small‐angle neutron scattering, confocal laser scanning microscopy, and fluorescence correlation spectroscopy. The study indicates the prospect of constructing functional nanoobjects by the self‐assembly of charged molecules in aqueous solution.

     

Rapid isolation and quantification of extracellular vesicles from suspension-adapted human embryonic kidney cells using capillary-channeled polymer fiber spin-down tips

Exosomes, a subset of extracellular vesicles (EVs, 30–200-nm diameter), serve as biomolecular snapshots of their cell of origin and vehicles for intercellular communication, playing roles in biological processes, including homeostasis maintenance and immune modulation. The large-scale processing of exosomes for use as therapeutic vectors has been proposed, but these applications are limited by impure, low-yield recoveries from cell culture milieu (CCM). Current isolation methods are also limited by tedious and laborious workflows, especially toward an isolation of EVs from CCM for therapeutic applications. Employed is a rapid (<10 min) EV isolation method on a capillary-channeled polymer fiber spin-down tip format. EVs are isolated from the CCM of suspension-adapted human embryonic kidney cells (HEK293), one of the candidate cell lines for commercial EV production. This batch solid-phase extraction technique allows 10¹² EVs to be obtained from only 100-µl aliquots of milieu, processed using a benchtop centrifuge. The tip-isolated EVs were characterized using transmission electron microscopy, multi-angle light scattering, absorbance quantification, an enzyme-linked immunosorbent assay to tetraspanin marker proteins, and a protein purity assay. It is believed that the demonstrated approach has immediate relevance in research and analytical laboratories, with opportunities for production-level scale-up projected.     

Bottom-Up Preparation of Phase-Separated Polymersomes

A bottom-up approach to fabricating monodisperse, two-component polymersomes that possess phase-separated (“patchy”) chemical topology is presented. This approach is compared with already-existing top-down preparation methods for patchy polymer vesicles, such as film rehydration. These findings demonstrate a bottom-up, solvent-switch self-assembly approach that produces a high yield of nanoparticles of the target size, morphology, and surface topology for drug delivery applications, in this case patchy polymersomes of a diameter of ≈50 nm. In addition, an image processing algorithm to automatically calculate polymersome size distributions from transmission electron microscope images based on a series of pre-processing steps, image segmentation, and round object identification is presented.     

Self‐Assembly of Amphiphilic Block Copolymer‐Tethered Nanoparticles: a New Approach to Nanoscale Design of Functional Materials

Colloidal molecules constructed from polymers and nanoparticles (NPs) have recently emerged as a novel class of building blocks for assembling functional hybrid materials. Particularly, self‐assembly of amphiphilic block copolymer (BCP)‐tethered NPs (BNPs) has shown great promise in the nanoscale design of functional hybrid materials. On the one hand, structurally the BNPs can be considered as molecular equivalents that are capable of self‐assembly at multiple hierarchical levels. On the other hand, the assembly of BNPs shows significant differences from molecular assembly due to their large dimension, complex geometry, and multi‐scale interactions involved in the assembly process. The manipulation of BCPs localized near the surface of the NPs offers an effective tool for engineering the interactions between NPs and hence the complexity of NP assembly. In this Feature Article, recent progresses on the self‐assembly of BNPs into functional materials are summarized. First, major strategies for assembling amphiphilic BNPs are highlighted. Secondly, the application of hybrid nanostructures (e.g., vesicles) assembled from BNPs in the field of biomedical imaging and delivery is discussed. Finally, current challenges and perspectives at this frontier are outlined.