Structural Determinants of Stimuli-Responsiveness in Amphiphilic Macromolecular Nano-assemblies

Polymersome-based nanomotors: preparation, motion control, and biomedical applications

Polymersome-based nanomotors represent a cutting-edge development in nanomedicine, merging the unique vesicular properties of polymersomes with the active propulsion capabilities of synthetic nanomotors. As a vesicular structure enclosed by a bilayer membrane, polymersomes can encapsulate both hydrophilic and hydrophobic cargoes. In addition, their physical-chemical properties such as size, morphology, and surface chemistry are highly tunable, which makes them ideal for various biomedical applications. The integration of motility into polymersomes enables them to actively navigate biological environments and overcome physiological barriers, offering significant advantages over passive delivery platforms. Recent breakthroughs in fabrication techniques and motion control strategies, including chemically, enzymatically, and externally driven propulsion, have expanded their potential for drug delivery, biosensing, and therapeutic interventions. Despite these advancements, key challenges remain in optimizing propulsion efficiency, biocompatibility, and in vivo stability to translate these systems into clinical applications. In this perspective, we discuss recent advancements in the preparation and motion control strategies of polymersome-based nanomotors, as well as their biomedical-related applications. The molecular design, fabrication approaches, and nanomedicine-related utilities of polymersome-based nanomotors are highlighted, to envisage the future research directions and further development of these systems into effective, precise, and smart nanomedicines capable of addressing critical biomedical challenges.

Synthesis of pH-Responsive Hyperbranched Polyesters by Thiol-Acrylate Michael Addition Reaction and Versatile Post-Polymerization Functionalization

Thiol-acrylate Michael addition reaction has been utilized as for the synthesis of hyperbranched polyesters with a sulfur atom located at the β-position of the ester carbonyl group, through the A2+B3 addition approach from a dithiol (A2) and tri-acrylate (B3) monomer. This reaction occurs at room temperature, it is 100% atom efficient and produces well-defined hyperbranched polymer (HP) with a degree of branching ≈0.52. Unreacted acrylate groups were utilized for highly efficient post-polymerization functionalization with different functional thiols, producing new HPs with amphiphilic character and different peripheral functional groups. Size exclusion chromatography studies with one representative polymer revealed Mark-Houwink coefficient (α) 0.38, indicating a compact structure, as expected for a typical HP. The presence of the β-thiopropionate ester group in the backbone makes these polymers degradable under mild acidic conditions. Studies with model compounds confirm the slow hydrolysis of the ester linkage by neighboring group participation by the sulfur atom. Glucose functionalized HP, derived by post-polymerization functionalization, produces micelle-like nanoparticles in water with hydrophobic guest encapsulation ability and exhibits sustained release under mild acidic conditions. Such glyco-polymer aggregates show excellent glyco-cluster effect with Concanavaline A (Ka ≈5 × 104 m-1).

Molecular-Based Nanoplatform Leads to the Formation of a Self-Indicating Responsive Drug Delivery System

We report the design and biological evaluation of a nanoplatform featuring controllable aggregation-induced emission (AIE) behavior. The free rotation of benzene rings (4-(1,2,2-triphenylvinyl) benzaldehyde) largely suppresses fluorescence in the pure organic phase. However, water-induced molecular aggregation enhances the fluorescence signal. The delivery system follows the membrane-cytoplasm-nucleus route and it leads to apoptosis in two cancer cells (U937 cells and Hela cells). The AIE moiety accumulates in the cytoplasm, emitting a bright-blue signal, but the anticancer drug doxorubicin selectively targets the nucleus with unique red emission. The current noninvasive method with DOX-triggered apoptosis holds promise for tumor diagnosis and real-time imaging.

Predicting the Key Properties of a Modified Product to Pre-Select a Pluronic F127 Modification Scheme for Preparing High-Quality Nano-Micelles

Hydrophobic modification alters the properties of Pluronic F127 to form micelles more efficiently and enhances its drug-loading capacity. However, selecting the appropriate hydrophobic group for modification is laborious. In this paper, we propose an efficient approach for predicting key parameters to select hydrophobic groups for F127 modification prior to synthesis, in order to improve the formability and stability of the micelles. The results of nuclear magnetic resonance and isothermal titration calorimetry were utilized to establish a function for predicting the hydrophile-lipophile balance, critical micelle concentration, and Gibbs free energy of the products based on the structure of raw material. These predicted values can assist us in selecting suitable hydrophobic groups for F127 modification. Subsequently, we successfully tested our method and validated our work using pharmaceutical evaluation methods, such as appearance observation, particle size measurement, drug loading determination, equilibrium binding rate assessment, storage stability testing, and the plotting of accumulation release curves. Therefore, we suggest that our work could provide a model linking the molecular structure to properties, with the purpose of pre-selecting modification products that have advantages in micelle preparation. This can facilitate the application of F127 in preparing nano-micelles.

Optimal Method to Realize Quantitative Detection of 1D and 2D Nanoassemblies Based on AIE-Active Bolaamphiphilic Molecules

Controllable transformation between the bolaamphiphilic molecule assemblies with different morphological nanostructures represents an exciting new direction for materials. However, there are still significant challenges for the quantitative detection and real-time monitoring of a controllable nanoself-assembly process due to insufficient measuring methods. Herein, we propose a new and effective fluorescence technology for realizing quantitative detection of a controllable conversion process of one-dimensional (1D)/two-dimensional (2D) nanoassemblies by introducing AIEgens as the fluorescence signal part. First, an aggregation-induced emission (AIE)-active bolaamphiphilic molecule (TPE-C8-Br) was designed and synthesized by incorporating tetraphenylethene (TPE) as the chromophore into the cationic amphiphile. Subsequently, the 1D nanofibrous morphology of TPE-C8-Br was successfully converted into the 2D rectangular and circular sheet of tosylate (TPE-C8-Ts) and sodium 1-hexanesulfonate (TPE-C8-HS) with the same molecular skeleton by the simple counterion change, respectively. Interestingly, all 2D nanoassemblies exhibited a stronger fluorescence sensitization effect than that of the 1D nanoassembly at the concentration above the critical micelle concentration (CMC) due to the higher degree of aggregation; thus, the rotation of the AIE-active TPE moiety is more restricted in TPE-C8-Ts and TPE-C8-HS. More meaningfully, a rather good linear correlation (FI = 3174.86 + 5282.29MP, R2 = 0.999) and a quadratic correlation (FI = 2113.71 + 5163.56MP - 2966.07MP2) were obtained between the molar percentage (MP) of the 2D nanoassembly and the fluorescence intensity (FI). The two proposed methods respond very well with regard to dependability, which can be used for the quantitative calculation of the molar ratio of 1D and 2D components in the controllable nanoself-assembly process. Therefore, this work offers an efficient and practical method for realizing the dynamic monitoring and quantitative detection of mutual conversion between different nanoassemblies.

Antibody-Directing Antibody Conjugates (ADACs) Enabled by Orthogonal Click Chemistry for Targeted Intracellular Delivery

Using orthogonal click chemistries for efficient nanoscale self-assembly, a new antibody-directing antibody conjugate (ADAC) nanogel is generated. In this system, one of the antibodies is displayed on the nanogel surface to specifically recognize cell-surface epitopes while the other antibody is encapsulated inside the nanogel core. The system is programmed to release the latter antibody in its functional form in the cytosolic environment of a specific cell to engage intracellular targets. ADACs offer a potential solution to harness the advantages seen with antibody-drug conjugates (ADCs) to deliver therapeutic cargos to specific tissues, but with the added capability of carrying biologics as the cargo. In this manuscript, this potential is demonstrated through delivery of antibodies against intracellular targets in specific cells. This platform offers new avenues for precise therapeutic interventions and the potential to address previously "undruggable" cellular targets.

Strategies, Challenges, and Prospects of Nanoparticles in Gynecological Malignancies

Gynecologic cancers are a significant health issue for women globally. Early detection and successful treatment of these tumors are crucial for the survival of female patients. Conventional therapies are often ineffective and harsh, particularly in advanced stages, necessitating the exploration of new therapy options. Nanotechnology offers a novel approach to biomedicine. A novel biosensor utilizing bionanotechnology can be employed for early tumor identification and therapy due to the distinctive physical and chemical characteristics of nanoparticles. Nanoparticles have been rapidly applied in the field of gynecologic malignancies, leading to significant advancements in recent years. This study highlights the significance of nanoparticles in treating gynecological cancers. It focuses on using nanoparticles for precise diagnosis and continuous monitoring of the disease, innovative imaging, and analytic methods, as well as multifunctional drug delivery systems and targeted therapies. This review examines several nanocarrier systems, such as dendrimers, liposomes, nanocapsules, and nanomicelles, for gynecological malignancies. The review also examines the enhanced therapeutic potential and targeted delivery of ligand-functionalized nanoformulations for gynecological cancers compared to nonfunctionalized anoformulations. In conclusion, the text also discusses the constraints and future exploration prospects of nanoparticles in chemotherapeutics. Nanotechnology will offer precise methods for diagnosing and treating gynecological cancers.

Gas-Responsive and Gas-Releasing Polymer Assemblies

In order to explore the unique physiological roles of gas signaling molecules and gasotransmitters in vivo, chemists have engineered a variety of gas-responsive polymers that can monitor their changes in cellular milieu, and gas-releasing polymers that can orchestrate the release of gases. These have advanced their potential applications in the field of bio-imaging, nanodelivery, and theranostics. Since these polymers are of different chain structures and properties, the morphology of their assemblies will manifest distinct transitions after responding to gas or releasing gas. In this review, we summarize the fundamental design rationale of gas-responsive and gas-releasing polymers in structure and their controlled transition in self-assembled morphology and function, as well as present some perspectives in this prosperous field. Emerging challenges faced for the future research are also discussed.

Design, Synthesis, and Acid-Responsive Disassembly of Shell-Sheddable Block Copolymer Labeled with Benzaldehyde Acetal Junction

Smart nanoassemblies degradable through the cleavage of acid-labile linkages have attracted significant attention because of their biological relevance found in tumor tissues. Despite their high potential to achieve controlled/enhanced drug release, a systematic understanding of structural factors that affect their pH sensitivity remains challenging, particulary in the consruction of effective acid-degradable shell-sheddable nanoassemblies. Herein, the authors report the synthesis and acid-responsive degradation through acid-catalyzed hydrolysis of three acetal and ketal diols and identify benzaldehyde acetal (BzAA) exhibiting optimal hydrolysis profiles in targeted pH ranges to be a suitable candidate for junction acid-labile linkage. The authors explore the synthesis and aqueous micellization of well-defined poly(ethylene glycol)-based block copolymer bearing BzAA linkage covalently attached to a polymethacrylate block for the formation of colloidally-stable nanoassemblies with BzAA groups at core/corona interfaces. Promisingly, the investigation on acid-catalyzed hydrolysis and disassembly shows that the formed nanoassemblies meet the criteria for acid-degradable shell-sheddable nanoassemblies: slow degradation at tumoral pH = 6.5 and rapid disassembly at endo/lysosomal pH = 5.0, while colloidal stability at physiological pH = 7.4. This work guides the design principle of acid-degradable shell-sheddable nanoassemblies bearing BzAA at interfaces, thus offering the promise to address the PEG dilemma and improve endocytosis in tumor-targeting drug delivery.