Aggregate (Hoboken, N.J.)最新文献

Droplet-based bioprinting has shown remarkable potential in tissue engineering and regenerative medicine. However, it requires bioinks with low viscosities, which makes it challenging to create complex 3D structures and spatially pattern them with different materials. This study introduces a novel approach to bioprinting sophisticated volumetric objects by merging droplet-based bioprinting and cryobioprinting techniques. By leveraging the benefits of cryopreservation, we fabricated, for the first time, intricate, self-supporting cell-free or cell-laden structures with single or multiple materials in a simple droplet-based bioprinting process that is facilitated by depositing the droplets onto a cryoplate followed by crosslinking during revival. The feasibility of this approach is demonstrated by bioprinting several cell types, with cell viability increasing to 80%–90% after up to 2 or 3 weeks of culture. Furthermore, the applicational capabilities of this approach are showcased by bioprinting an endothelialized breast cancer model. The results indicate that merging droplet and cryogenic bioprinting complements current droplet-based bioprinting techniques and opens new avenues for the fabrication of volumetric objects with enhanced complexity and functionality, presenting exciting potential for biomedical applications.

Existential state of solutes substantially affects the efficiency and direction of various chemical and biological processes, about which current consensus is still limited at macro and micro levels. At the trace level, solutes assume a pivotal role across a spectrum of critical fields. However, their existential states, especially at interfaces, remain largely elusive. Herein, an exceptional evolution of solute molecules is unveiled from micro to trace, solution to interface, with the aid of surface-enhanced Raman spectroscopy, extinction, DLS and theoretical simulations. Given predominant existence of monomers within the solution, these aggregates dominate the interfacial behavior of solute molecules. Moreover, a universal, aggregate-controlled mechanism is demonstrated that aggregates triggered by cosolvent, which can dramatically promote efficiency of catalytic reactions. The results provide novel insights into the interaction mechanisms between reactants and catalysts, potentially offering fresh perspectives for the manipulation of multiphase catalysis and related biological processes.

The development of tumor drug microcarriers has attracted considerable interest due to their distinctive therapeutic performances. Current attempts tend to elaborate on the micro/nano-structure design of the microcarriers to achieve multiple drug delivery and spatiotemporal responsive features. Here, the desired hydrogel microspheres are presented with spatiotemporal responsiveness for the treatment of gastric cancer. The microspheres are generated based on inverse opals, their skeleton is fabricated by biofriendly hyaluronic acid methacrylate (HAMA) and gelatin methacrylate (GelMA), and is then filled with a phase-changing hydrogel composed of fish gelatin and agarose. Besides, the incorporated black phosphorus quantum dots (BPQDs) within the filling hydrogel endow the microspheres with outstanding photothermal responsiveness. Two antitumor drugs, sorafenib (SOR) and doxorubicin (DOX), are loaded in the skeleton and filling hydrogel, respectively. It is found that the drugs show different release profiles upon near-infrared (NIR) irradiation, which exerts distinct performances in a controlled manner. Through both in vitro and in vivo experiments, it is demonstrated that such microspheres can significantly reduce tumor cell viability and enhance the efficiency in treating gastric cancer, indicating a promising stratagem in the field of drug delivery and tumor therapy.

Single-drug therapies or monotherapies are often inadequate, particularly in the case of life-threatening diseases like cancer. Consequently, combination therapies emerge as an attractive strategy. Cancer nanomedicines have many benefits in addressing the challenges faced by small molecule therapeutic drugs, such as low water solubility and bioavailability, high toxicity, etc. However, it remains a significant challenge in encapsulating two drugs in a nanoparticle. To address this issue, computational methodologies are employed to guide the rational design and synthesis of dual-drug-loaded polymer nanoparticles while achieving precise control over drug loading. Based on the sequential nanoprecipitation technology, five factors are identified that affect the formulation of drug candidates into dual-drug loaded nanoparticles, and then screened 176 formulations under different experimental conditions. Based on these experimental data, machine learning methods are applied to pin down the key factors. The implementation of this methodology holds the potential to significantly mitigate the complexities associated with the synthesis of dual-drug loaded nanoparticles, and the co-assembly of these compounds into nanoparticulate systems demonstrates a promising avenue for combination therapy. This approach provides a new strategy for enabling the streamlined, high-throughput screening and synthesis of new nanoscale drug-loaded entities.

Surface chirality plays an important role in determining the biological effect, but the molecular nature beyond stereoselectivity is still unknown. Herein, through surface-enhanced infrared absorption spectroscopy, electrochemistry, and theoretical simulations, we found diasteromeric monolayers induced by assembled density on chiral gold nanofilm and identified the positive contribution of water dipole potential at chiral interface and their different interfacial interactions, which result in a difference both in the positive dipoles of interfacial water compensating the negative surface potential of the SAM and in the hindrance effect of interface dehydration, thereby regulating the interaction between amyloid-β peptide (Aβ) and N-isobutyryl-cysteine (NIBC). Water on L-NIBC interface which shows stronger positive dipole potential weakens the negative surface potential, but its local weak binding to the isopropyl group facilitates hydrophobic interaction between Aβ42 and L-NIBC and resulted fiber aggregate. Conversely, electrostatic interaction between Aβ42 and D-NIBC induces spherical oligomer. These findings provide new insight into molecular nature of chirality-regulated biological effect.

Chirality and luminescence are important for both chemistry and biology, which are highly influenced by aggregation. In this work, a pair of metalated tetraphenylethylene(TPE)-based organic cage enantiomers are reported, which feature a quadrangular prismatic cage structure. These homochiral cages exhibit concentration-dependent chiral behaviors alongside a propensity for thermodynamic aggregation. Aggregation caused quench effect is found for these cages accompanying the increasing of the concentrations. When a poor solvent is added to produce a kinetical aggregation, the aggregation-annihilation circular dichroism and aggregation-induced emission behaviors are observed for these enantiomeric cages. By comparing these observations with the photophysical behaviors of a pair of structurally similar organic molecular enantiomers, the unique photophysical properties observed are intricately linked to the metal-integrated TPE-functionalized cage structures.

Proteins play a vital role in different biological processes by forming complexes through precise folding with exclusive inter- and intra-molecular interactions. Understanding the structural and regulatory mechanisms underlying protein complex formation provides insights into biophysical processes. Furthermore, the principle of protein assembly gives guidelines for new biomimetic materials with potential applications in medicine, energy, and nanotechnology. Atomic force microscopy (AFM) is a powerful tool for investigating protein assembly and interactions across spatial scales (single molecules to cells) and temporal scales (milliseconds to days). It has significantly contributed to understanding nanoscale architectures, inter- and intra-molecular interactions, and regulatory elements that determine protein structures, assemblies, and functions. This review describes recent advancements in elucidating protein assemblies with in situ AFM. We discuss the structures, diffusions, interactions, and assembly dynamics of proteins captured by conventional and high-speed AFM in near-native environments and recent AFM developments in the multimodal high-resolution imaging, bimodal imaging, live cell imaging, and machine-learning-enhanced data analysis. These approaches show the significance of broadening the horizons of AFM and enable unprecedented explorations of protein assembly for biomaterial design and biomedical research.

Highly sensitive stimuli-responsive luminescent materials are crucial for applications in optical sensing, security, and anticounterfeiting. Here, we report two zero-dimensional (0D) copper(I) halides, (TEP)₂Cu₂Br₄, (TEP)₂Cu₄Br₆, and 1D (TEP)₃Ag₆Br₉, which are comprised of isolated [Cu₂Br₄]²⁻, [Cu₄Br₆]²⁻, and [Ag₆Br₉]³⁻ polyanions, respectively, separated by TEP⁺ (tetraethylphosphonium [TEP]) cations. (TEP)₂Cu₂Br₄ and (TEP)₂Cu₄Br₆ demonstrate greenish-white and orange-red emissions, respectively, with near unity photoluminescence quantum yields, while (TEP)₃Ag₆Br₉ is a poor light emitter. Optical spectroscopy measurements and density-functional theory calculations reveal that photoemissions of these compounds originate from self-trapped excitons due to the excited-state distortions in the copper(I) halide units. Crystals of Cu(I) halides are radioluminescence active at room temperature under both X- and γ-rays exposure. The light yields up to 15,800 ph/MeV under 662 keV γ-rays of ¹³⁷Cs suggesting their potential for scintillation applications. Remarkably, (TEP)₂Cu₂Br₄ and (TEP)₂Cu₄Br₆ are interconvertible through chemical stimuli or reverse crystallization. In addition, both compounds demonstrate luminescence on-off switching upon thermal stimuli. The sensitivity of (TEP)₂Cu₂Br₄ and (TEP)₂Cu₄Br₆ to the chemical and thermal stimuli coupled with their ultrabright emission allows their consideration for applications such as solid-state lighting, sensing, information storage, and anticounterfeiting.

The aggregation of topological spin textures at nano and micro scales has practical applications in spintronic technologies. Here, the authors report the in-plane current-induced proliferation and aggregation of bimerons in a bulk chiral magnet. It is found that the spin-transfer torques can induce the proliferation and aggregation of bimerons only in the presence of an appropriate out-of-plane magnetic field. It is also found that a relatively small damping and a relatively large non-adiabatic spin-transfer torque could lead to more pronounced bimeron proliferation and aggregation. Particularly, the current density should be larger than a certain threshold in order to trigger the proliferation; namely, the bimerons may only be driven into translational motion under weak current injection. Besides, the authors find that the aggregate bimerons could relax into a deformed honeycomb bimeron lattice with a few lattice structure defects after the current injection. The results are promising for the development of bio-inspired spintronic devices that use a large number of aggregate bimerons. The findings also provide a platform for studying aggregation-induced effects in spintronic systems, such as the aggregation-induced lattice phase transitions.

Thermally activated delayed fluorescence (TADF) molecules are regarded as promising materials for realizing high-performance organic light-emitting diodes (OLEDs). The connecting groups between donor (D) and acceptor (A) units in D–A type TADF molecules could affect the charge transfer and luminescence performance of TADF materials in aggregated states. In this work, we design and synthesize four TADF molecules using planar and twisted linkers to connect the aza-azulene donor (D) and triazine acceptor (A). Compared with planar linkers, the twisted ones (Az-NP-T and Az-NN-T) can enhance A–A aggregation interaction between adjacent molecules to balance hole and electron density. As a result, highly efficient and stable deep-red top-emission OLEDs with a high electroluminescence efficiency of 57.3% and an impressive long operational lifetime (LT₉₅ ∼ 30,000 h, initial luminance of 1000  cd  m⁻²) are obtained. This study provides a new strategy for designing more efficient and stable electroluminescent devices through linker aggregation engineering in donor–acceptor molecules.