Ultralong Circulating Lollipop‐Like Nanoparticles Assembled with Gossypol,Doxorubicin, and Polydopamine via π–π Stacking for Synergistic Tumor Therapy

Long blood circulation in vivo remains a challenge to dual‐drug‐loaded nanocarriers for synergistic chemotherapy. Herein, a novel strategy to prepare lollipop‐like dual‐drug‐loaded nanoparticles (DOX–PDA–gossypol NPs) is developed based on the self‐assembly of gossypol, doxorubicin (DOX), and polydopamine (PDA) via π–π stacking. Dopamine polymerizes to PDA and fills the gaps between the gossypol and DOX molecules to form the super compact long‐circulating nanoparticles. The DOX–PDA–gossypol NPs show a suitable particle size of 59.6 ± 9.6 nm, high drug loading of 91%, superb stability, high maximum‐tolerated dose (MTD) of over 60 mg kg^‐1, and negligible toxicity. These NPs also exhibit pH‐dependent drug release and low combination index (0.23). Notably, they show dramatically ultralong blood circulation (>192 h) with elimination half times 458‐fold and 258‐fold longer than that of free DOX and free gossypol, respectively. These values are markedly higher than most of the reported results. Therefore, the DOX–PDA–gossypol NPs have a high tumor accumulation of 12% remaining on the 8th day postinjection. This characteristic contributes to the excellent tumor comprehensive synergistic therapeutic efficacy (TIR > 90%) with low administration dosage and is benefitted for widening the drug therapeutic window. Thus, the proposed strategy has remarkable potential for tumor synergistic therapy.     

Surface Regulation Towards Stimuli‐Responsive Luminescence of Ultrasmall Thiolated Gold Nanoparticles for Ratiometric Imaging

The surface chemistry of the ultrasmall thiolated gold nanoparticles (AuNPs, < 3.0 nm) plays key roles in both governing the intrinsic emission and establishing interfaces surrounded by various amine‐containing biomolecules in the biomedical applications such as imaging, targeting, and diagnostics. However, a fundamental understanding of the surface ligand's role in the stimuli‐responsive emissions of AuNPs toward the amine molecules is currently lacking. Here, through investigation of the thiolate surface and exotic amine structures, it is discovered that the nucleophilic amines tend to closely bind the electrophilic gold surface, generating a high‐energy stimuli‐responsive emission from the low‐energy intrinsically emitting AuNPs. Both the intrinsic and stimuli‐responsive emissions show a unique amine concentration‐dependent ratiometric pattern for quantitative assessments of important biogenic amines in the biological samples. This discovery opens a new pathway to the design of stimuli‐responsive AuNPs, and would promote more experimental and theoretical research on the application‐driven surface engineering for advanced biological applications.     

Metastable Zirconium Phosphate under Nanoconfinement with Superior Adsorption Capability for Water Treatment

In confined space with length scale of several nanometers, the phase behavior of matter, e.g., nucleation and crystallization, is completely different from its analogue in bulk. However, in environmental applications, the relationship between the nanoconfined crystallization behavior of inorganic crystals and their properties for pollutant removal is rarely elucidated. Herein, an unusual formation of zirconium phosphate (ZrP) crystals as a mixture of both thermodynamically stable α‐ and metastable γ‐phases inside the nanoconfinement of 7.9 nm pores of mesoporous polystyrene (MPS) is reported. This consequently changes the interaction between ZrP and toxic metal cations from nonspecific electrostatic attraction of normal α‐ZrP to highly specific inner‐sphere coordination of nanoconfined γ‐ZrP, which exhibits remarkable reactivity as well as reusability for the removal of toxic metals. The results of this study contribute to a better understanding of the use of nanoconfinement for the regulation of material properties.     

High‐Tensile Strength,Composite Bijels through Microfluidic Twisting

Rope making is a millennia old technique to collectively assemble numerous weak filaments into flexible and high tensile strength bundles. However, delicate soft matter fibers lack the robustness to be twisted into bundles by means of mechanical rope making tools. Here, weak microfibers with tensile strengths of a few kilopascals are combined into ropes via microfluidic twisting. This is demonstrated for recently introduced fibers made of bicontinuous interfacially jammed emulsion gels (bijels). Bijels show promising applications in use as membranes, microreactors, energy and healthcare materials, but their low tensile strength make reinforcement strategies imperative. Hydrodynamic twisting allows to produce continuous bijel fiber bundles of controllable architecture. Modelling the fluid flow field reveals the bundle geometry dependence on a subtle force balance composed of rotational and translational shear stresses. Moreover, combining multiple bijel fibers of different compositions enables the introduction of polymeric support fibers to raise the tensile strength to tens of megapascals, while simultaneously preserving the liquid like properties of the bijel fibers for transport applications. Hydrodynamic twisting shows potentials to enable the combination of a wide range of materials resulting in composites with features greater than the sum of their parts.     

含纳米铝颗粒的JP-10凝胶燃料理化及流变性能

为了提高液体燃料能量并解决纳米金属颗粒在燃料中沉降的问题,研究以有机小分子凝胶剂(LMWG)为凝胶因子,制备了含有纳米铝颗粒的JP-10凝胶燃料,测定了最低凝胶剂含量和凝胶相转变温度,探讨了凝胶剂含量和纳米铝颗粒含量对燃料密度、黏度、离心稳定性等物理化学性能的影响,通过剪切变稀测试、触变性测试、应变扫描、频率扫描等测试了凝胶燃料的流变性能。结果表明,纳米铝颗粒在LMWG/JP-10凝胶燃料中稳定分散,同时凝胶燃料可以在施加剪切力或加热的条件下实现凝胶态与液态的相互转变;铝颗粒的加入显著提高了燃料的密度、体积热值和黏度,当纳米铝颗粒含量为25%时,2%LMWG/JP-10的密度为1.156 g·mL^-1,剪切黏度为840 mPa·s,体积热值为45.8 MJ·L^-1。铝颗粒含量少于25%时会影响凝胶体系的稳定性,但当铝颗粒含量达到25%时,体系的稳定性超过同等LMWG凝胶剂含量的纯燃料。铝颗粒的加入显著增强凝胶体系的机械强度和结构稳定性,但燃料依旧保持良好的剪切变稀特性,并且无法恢复至受剪切作用前的状态。     

Low‐Cost Post‐Growth Treatments of Crystalline Silicon Nanoparticles Improving Surface and Electronic Properties

Freestanding silicon nanocrystals (Si‐ncs) offer unique optical and electronic properties for new photovoltaic, thermoelectric, and other electronic devices. A method to fabricate Si‐ncs which is scalable to industrial usage has been developed in recent years. However, barriers to the widespread utilization of these nanocrystals are the presence of charge‐trapping defects and an oxide shell formed upon ambient atmosphere exposure hindering the charge transport. Here, we exploit low‐cost post‐growth treatment routes based on wet‐etching in hydrofluoric acid plus surface hydrosilylation or annealing enabling a complete native oxide removal and a reduction of the defect density by up to two orders of magnitude. Moreover, when compared with only H‐terminated Si‐ncs we report an enhancement of the conductivity by up to a factor of 400 for films of HF etched and annealed Si‐ncs, which retain a defect density below that of untreated Si‐ncs even after several months of air exposure. Further, we demonstrate that HF etched and hydrosilylated Si‐ncs are extremely stable against oxidation and maintain a very low defect density after a long‐term storage in air, opening the possibility of device processing in ambient atmosphere.     

Locally Welded Silver Nano‐Network Transparent Electrodes with High Operational Stability by a Simple Alcohol‐Based Chemical Approach

As an indispensable aspect of emerging flexible optoelectronics, flexible transparent electrodes, especially those comprised of metal nanowires, have attracted great attentions recently. Welding the nanowire junctions is an effective strategy for reducing the sheet resistance and improving the operational stability of flexible nanowire electrode in practical applications. Herein, a simple alcohol‐based solution approach is proposed to weld crossed silver nanowires by chemically growing silver “solder” at the junctions of the nanowires, forming transparent silver nano‐network electrodes with improved electrical conductivity and operational stability. Remarkably, silver nano‐networks can be rapidly formed by this simple approach under ambient condition and room temperature, requiring no assistance from heat, light, electrical current, or mechanical pressure. Furthermore, our results show that the nano‐network electrode formed from large diameter nanowires offers a better operational stability, whose trend is opposite to that of the untreated electrodes. To demonstrate the potential application of the highly stable silver nano‐network from large diameter nanowires, organic solar cells fabricated on the nano‐network electrode incorporated with silicon dioxide nanoparticles achieve comparable performance to the ITO control device. Consequently, strategy demonstrated in this work can contribute to low‐cost and highly stable transparent electrodes in emerging flexible optoelectronics.     

Photothermal Modulation of Depression-Related Ion Channel Function through Conjugated Polymer Nanoparticles

Considering recent breakthroughs in the field of optogenetics, a powerful tool is established in the present study to modulate the activities of target neurons through the application of light-based methods. Near-infrared (NIR) light enables the penetration of deep-tissue. As a result, it can be used to modulate the functions of proteins/cells. Herein, it is aimed to develop a NIR light-sensitive drug delivery system to spatially and temporally control the activation of the loaded drug at the stimulation sites through its release from a nanoparticle sensitive to NIR. Owing to their excellent photothermal effect under NIR irradiation, the nanoparticles are found to penetrate the blood-brain barrier effectively, ultimately reaching neurons. Furthermore, by loading fasudil, a selective activator of the Kv7.4 potassium channel, into the precisely designed and synthesized NIR light-sensitive nanoparticles, the firing frequency of dopaminergic neurons in the ventral tegmental area is found to be remarkably reduced upon NIR light irradiation. Such findings shed light on a new concept that can be used for developing more selective drug therapies for the treatment of diseases, such as major depression.