Recent Progress in Fluorescent Vesicles with Aggregation-induced Emission

Microfluidics-Assisted Polymer Vesicle Budding in Emulsion Systems: A Promising Approach for the Preparation and Application of Polymer Vesicles

The challenge of producing polymer vesicles remains difficult, despite numerous attempts to modulate the kinetics of polymer vesicle budding and achieve precise control over the membrane characteristics. An innovative approach that incorporates the use of copolymer-loaded single-emulsion droplets is proposed to address this challenge. This method enables the precise manipulation of micelles and polymer vesicles' composition, structures and dimensions. The emulsion contracts and forms microspheres when the copolymer concentrations exceed > 0.5 wt%, resulting in the formation of nano polymer vesicles. Conversely, the copolymer spontaneously forms micro polymer vesicles and micelles through vesicle budding at lower concentrations. The spontaneous production of vesicles and micelles can be induced by modifying the copolymer concentration in the emulsion. Our discoveries have a significant impact relative to the development of copolymer membranes and contribute to an enhanced comprehension of the mass manufacturing of polymer vesicles from single emulsions.

Aggregation-Induced Emission-Active Nanostructures: Beyond Biomedical Applications

The discovery of aggregation-induced emission (AIE) phenomenon in 2001 has had a significant impact on materials development across different research disciplines. AIE-active materials have been widely exploited for various applications in optoelectronics, sensing, biomedical, and stimuli-responsive systems, etc. This is made possible by integrating AIE features with other fields of science and engineering, such as nanoscience and nanotechnology. AIE has been extensively employed, particularly for biomedical applications, such as biosensing, bioimaging, and theranostics. However, development of AIE-based nanotechnology for other applications is comparatively less, although there have been increasing research activities in recent years. Given the significance and potential of the marriage between AIE hallmark and nanotechnology in AIE-active materials development, this review article summarizes and showcases the latest research efforts in AIE-based nanomaterials, including nanomaterials synthesis and their nonbiomedical applications, such as sensing, optoelectronics, functional coatings, and stimuli-responsive systems. A perspective on the outlook of AIE-based nanostructured materials and relevant nanotechnology for nonbiomedical applications will be provided, giving an insight into how to design AIE-active nanostructures as well as their applications beyond the biomedical domain.

Intelligent design of polymersomes for antibacterial and anticancer applications

Polymersomes (or polymer vesicles) have attracted much attention for biomedical applications in recent years because their lumen can be used for drug delivery and their coronas and membrane can be modified with a variety of functional groups. Thus, polymersomes are very suitable for improved antibacterial and anticancer therapy. This review mainly highlighted recent advances in the synthetic protocols and design principles of intelligent antibacterial and anticancer polymersomes. Antibacterial polymersomes are divided into three categories: polymersomes as antibiotic nanocarriers, intrinsically antibacterial polymersomes, and antibacterial polymersomes with supplementary means including photothermal and photodynamic therapy. Similarly, the anticancer polymersomes are divided into two categories: polymersomes-based delivery systems and anticancer polymersomes with supplementary means. In addition, the bilateral relationship between bacteria and cancer is addressed, since more and more evidences show that bacteria may cause cancer or promote cancer progression. Finally, prospective on next-generation antibacterial and anticancer polymersomes are discussed. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Biology-Inspired Nanomaterials > Lipid-Based Structures.

Fabrication of pH/H2O2-responsive polyhedral oligomeric silsesquioxane self-assembled fluorescent vesicles for enhanced in vivo anti-tumor efficacy

Aim: The rational design of a fluorescence imaging-guided, highly efficient multiresponsive delivery system is important for improving drug delivery efficiency. Materials and methods: Herein, pH/H₂O₂-responsive polyhedral oligomeric silsesquioxane (POSS) molecule functionalized 4-(phenyl(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl)amino)benzaldehyde (OTB) copolymer (PEG-POSS-OTB) was synthesized to encapsulate doxorubicin (DOX) for precise drug delivery. Results: The self-assembly fluorescent vesicles exhibited excellent pH/H₂O₂-responsive drug release properties under physiological conditions and efficient drug-targeting ability. In vitro, compared with the DOX group, PEG-POSS-OTB fluorescent vesicles exhibited improved drug delivery and reduced toxicity. Importantly, we performed a proof-of-concept study demonstrating that PEG-POSS-OTB fluorescent vesicles were a high-efficiency nanoassembly drug-delivery platform for improving drug delivery efficiency. In vivo studies demonstrated that PEG-POSS-OTB vesicles with enhanced stability could be used in targeted drug delivery and controlled intelligent release.

Polymersomes with a smectic liquid crystal structure and AIE fluorescence

Fluorescent smectic polymersomes with aggregation-induced emission are prepared from an amphiphilic block copolymer containing a liquid crystal hydrophobic block and a tetraphenylethene-bearing unit between hydrophilic and hydrophobic blocks.

Asymmetric Vesicles Self-Assembled by Amphiphilic Sequence-Controlled Polymers

The asymmetric distribution of lipids on the inner and outer membranes of a cell plays a pivotal role in the physiological and immunological activities of life. It has inspired the elaboration of synthetic asymmetric vesicles for the discovery of advanced materials and functions. The asymmetric vesicles were generally prepared by amphiphilic block copolymers. We herein report on the formation of asymmetric vesicles self-assembled by amphiphilic sequence-controlled polymers with two hydrophilic segments SU and TEO. We also developed an efficient fluorescence titration method with europium(III) ions (Eu³⁺) to determine the uneven distribution of SU and TEO. SU units are preferentially located on the outer membrane and TEO on the inner membrane of the resulting vesicles, which is facilitated by the electrostatic repulsion of SU and the U-shaped folding of the hydrophobic backbone of the resulting polymers. This work shows that sequence-controlled polymers with alternating monomer sequence provide a powerful toolbox for the elaboration of important yet challenging self-assembled structures for emerging functions and properties.

Functional Polymer Systems with Aggregation-Induced Emission and Stimuli Responses

Functional polymer systems with stimuli responses have attracted great attention over the years due to their diverse range of applications. Such polymers are capable of altering their chemical and/or physical properties, such as chemical structures, chain conformation, solubility, shape, morphologies, and optical properties, in response to single or multiple stimuli. Among various stimuli-responsive polymers, those with aggregation-induced emission (AIE) properties possess the advantages of high sensitivity, fast response, large contrast, excellent photostability, and low background noise. The changes in fluorescence signal can be conveniently detected and monitored using portable instruments. The integration of AIE and stimuli responses into one polymer system provides a feasible and effective strategy for the development of smart polymers with high sensitivity to environmental variations. Here, we review the recent advances in the design, preparation, performance, and applications of functional synthetic polymer systems with AIE and stimuli responses. Various AIE-based polymer systems with responsiveness toward single physical or chemical stimuli as well as multiple stimuli are summarized with specific examples. The current challenges and perspectives on the future development of this research area will also be discussed at the end of this review.

CO2 -Activated Reversible Transition between Polymersomes and Micelles with AIE Fluorescence

Fluorescent polymersomes with both aggregation-induced emission (AIE) and CO₂ -responsive properties were developed from amphiphilic block copolymer PEG-b-P(DEAEMA-co-TPEMA) in which the hydrophobic block was a copolymer made of tetraphenylethene functionalized methacrylate (TPEMA) and 2-(diethylamino)ethyl methacrylate (DEAEMA) with unspecified sequence arrangement. Four block copolymers with different DEAEMA/TPEMA and hydrophilic/hydrophobic ratios were synthesized, and bright AIE polymersomes were prepared by nanoprecipitation in THF/water and dioxane/water systems. Polymersomes of PEG₄₅ -b-P(DEAEMA₃₆ -co-TPEMA₆ ) were chosen to study the CO₂ -responsive property. Upon CO₂ bubbling vesicles transformed to small spherical micelles, and upon Ar bubbling micelles returned to vesicles with the presence of a few intermediate morphologies. These polymersomes might have promising applications as sensors, nanoreactors, or controlled release systems.