Gold Nanoparticles Downregulate Interleukin‐1β‐Induced Pro‐Inflammatory Responses

Interleukin 1 beta (IL‐1β)‐dependent inflammatory disorders, such as rheumatoid arthritis and psoriasis, pose a serious medical burden worldwide, where patients face a lifetime of illness and treatment. Organogold compounds have been used since the 1930s to treat rheumatic and other IL‐1β‐dependent diseases and, though their mechanisms of action are still unclear, there is evidence that gold interferes with the transmission of inflammatory signalling. Here we show for the first time that citrate‐stabilized gold nanoparticles, in a size dependent manner, specifically downregulate cellular responses induced by IL‐1β both in vitro and in vivo. Our results indicate that the anti‐inflammatory activity of gold nanoparticles is associated with an extracellular interaction with IL‐1β, thus opening potentially novel options for further therapeutic applications.     

3D‐Structured Stretchable Strain Sensors for Out‐of‐Plane Force Detection

Stretchable strain sensors, as the soft mechanical interface, provide the key mechanical information of the systems for healthcare monitoring, rehabilitation assistance, soft exoskeletal devices, and soft robotics. Stretchable strain sensors based on 2D flat film have been widely developed to monitor the in‐plane force applied within the plane where the sensor is placed. However, to comprehensively obtain the mechanical feedback, the capability to detect the out‐of‐plane force, caused by the interaction outside of the plane where the senor is located, is needed. Herein, a 3D‐structured stretchable strain sensor is reported to monitor the out‐of‐plane force by employing 3D printing in conjunction with out‐of‐plane capillary force‐assisted self‐pinning of carbon nanotubes. The 3D‐structured sensor possesses large stretchability, multistrain detection, and strain‐direction recognition by one single sensor. It is demonstrated that out‐of‐plane forces induced by the air/fluid flow are reliably monitored and intricate flow details are clearly recorded. The development opens up for the exploration of next‐generation 3D stretchable sensors for electronic skin and soft robotics.     

Amyloid‐β Aggregation with Gold Nanoparticles on Brain Lipid Bilayer

Understanding and manipulating amyloid‐β (Aβ) aggregation provide key knowledge and means for the diagnosis and cure of Alzheimer's disease (AD) and the applications of Aβ‐based aggregation systems. Here, we studied the formation of various Aβ aggregate structures with gold nanoparticles (AuNPs) and brain total lipid extract‐based supported lipid bilayer (brain SLB). The roles of AuNPs and brain SLB in forming Aβ aggregates were studied in real time, and the structural details of Aβ aggregates were monitored and analyzed with the dark‐field imaging of plasmonic AuNPs that allows for long‐term in situ imaging of Aβ aggregates with great structural details without further labeling. It was shown that the fluid brain SLB platform provides the binding sites for Aβ and drives the fast and efficient formation of Aβ aggregate structures and, importantly, large Aβ plaque structures (>15 μm in diameter), a hallmark for AD, were formed without going through fibril structures when Aβ peptides were co‐incubated with AuNPs on the brain SLB. The dark‐field scattering and circular dichroism‐correlation data suggest that AuNPs were heavily involved with Aβ aggregation on the brain SLB and less α‐helix, less β‐sheet and more random coil structures were found in large plaque‐like Aβ aggregates.     

Encapsulation of Gold Nanoparticles into DNA Minimal Cages for 3D‐Anisotropic Functionalization and Assembly

Gold nanoparticles (AuNPs) endowed with anisotropic DNA valency are an important class of materials, as they can assemble into complex structures with a minimal number of DNA strands. However, methods to encode 3D DNA strand patterns on AuNPs with a controlled number of unique DNA strands in a predesigned spatial arrangement remain elusive. In this work, a simple one‐step method to yield such DNA‐decorated AuNPs is demonstrated, through encapsulating AuNPs into DNA minimal nanocages. The AuNP@DNA cage encapsulation complex inherits the 3D anisotropic molecular information from the DNA nanocage with enhanced structural stability. The DNA nanocage can be further functionalized and used as a building block for the self‐assembly of complex architectures, such as dimers and trimers, programmed assemblies with sequential growth DNA backbones and DNA origami.     

Solid‐State Nanopore Detection of Protein Complexes: Applications in Healthcare and Protein Kinetics

Protein conjugation provides a unique look into many biological phenomena and has been used for decades for molecular recognition purposes. In this study, the use of solid‐state nanopores for the detection of gp120‐associated complexes are investigated. They exhibit monovalent and multivalent binding to anti‐gp120 antibody monomer and dimers. In order to investigate the feasibility of many practical applications related to nanopores, detection of specific protein complexes is attempted within a heterogeneous protein sample, and the role of voltage on complexed proteins is researched. It is found that the electric field within the pore can result in unbinding of a freely translocating protein complex within the transient event durations measured experimentally. The strong dependence of the unbinding time with voltage can be used to improve the detection capability of the nanopore system by adding an additional level of specificity that can be probed. These data provide a strong framework for future protein‐specific detection schemes, which are shown to be feasible in the realm of a ‘real‐world’ sample and an automated multidimensional method of detecting events.     

Negatively Charged Gold Nanoparticles Inhibit Alzheimer's Amyloid‐β Fibrillization,Induce Fibril Dissociation,and Mitigate Neurotoxicity

Amyloids are pathogenic hallmarks in many neurodegenerative diseases such as amyloid‐β (Aβ) fibrils in Alzheimer's disease (AD). Here, the effect of gold nanoparticles (AuNPs) on amyloids is examined using Aβ as a model system. It is found that bare AuNPs inhibited Aβ fibrillization to form fragmented fibrils and spherical oligomers. Adding bare AuNPs to preformed Aβ fibrils results in ragged species where AuNPs bind preferentially to fibrils. Similar results are demonstrated with carboxyl‐ but not amine‐conjugated AuNPs. Co‐incubation of negatively charged AuNPs with Aβ relieved Aβ toxicity to neuroblastoma. Overall, it is demonstrated that AuNPs possessing negative surface potential serve as nano‐chaperones to inhibit and redirect Aβ fibrillization, which could contribute to applications for AD.     

TGF‐β1 Conjugated to Gold Nanoparticles Results in Protein Conformational Changes and Attenuates the Biological Function

Gold nanoparticles (AuNPs) are widely used as carriers or therapeutic agents due to their great biocompatibility and unique physical properties. Transforming growth factor‐beta 1 (TGF‐β1), a member of the cysteine‐knot structural superfamily, plays a pivotal role in many diseases and is known as an immunosuppressive agent that attenuates immune response resulting in tumor growth. The results reported herein reflect strong interactions between TGF‐β1 and the surface of AuNPs when incubated with serum‐containing medium, and demonstrate a time‐ and dose‐dependent pattern. Compared with other serum proteins that can also bind to the AuNP surface, AuNP–TGFβ1 conjugate is a thermodynamically favored compound. Epithelial cells undergo epithelial–mesenchymal transition (EMT) upon treatment with TGF‐β1; however, treatment with AuNPs reverses this effect, as detected by cell morphology and expression levels of EMT markers. TGF‐β1 is found to bind to AuNPs through S–Au bonds by X‐ray photoelectron spectroscopy. Fourier transform infrared spectroscopy is employed to analyze the conformational changes of TGF‐β1 on the surface of AuNPs. The results indicate that TGF‐β1 undergoes significant conformational changes at both secondary and tertiary structural levels after conjugation to the AuNP surface, which results in the deactivation of TGF‐β1 protein. An in vivo experiment also shows that addition of AuNPs attenuates the growth of TGF‐β1‐secreting murine bladder tumor 2 cells in syngeneic C3H/HeN mice, but not in immunocompromised NOD‐SCID mice, and this is associated with an increase in the number of tumor‐infiltrating CD4⁺ and CD8⁺ T lymphocytes and a decrease in the number of intrasplenic Foxp3(+) lymphocytes. The findings demonstrate that AuNPs may be a promising agent for modulating tumor immunity through inhibiting immunosuppressive TGF‐β1 signaling.     

3D Hollow α‐MnO2 Framework as an Efficient Electrocatalyst for Lithium–Oxygen Batteries

Lithium–oxygen (Li–O₂) batteries are attracting more attention owing to their superior theoretical energy density compared to conventional Li‐ion battery systems. With regards to the catalytically electrochemical reaction on a cathode, the electrocatalyst plays a key role in determining the performance of Li–O₂ batteries. Herein, a new 3D hollow α‐MnO₂ framework (3D α‐MnO₂) with porous wall assembled by hierarchical α‐MnO₂ nanowires is prepared by a template‐induced hydrothermal reaction and subsequent annealing treatment. Such a distinctive structure provides some essential properties for Li–O₂ batteries including the intrinsic high catalytic activity of α‐MnO₂, more catalytic active sites of hierarchical α‐MnO₂ nanowires on 3D framework, continuous hollow network and rich porosity for the storage of discharge product aggregations, and oxygen diffusion. As a consequence, 3D α‐MnO₂ achieves a high specific capacity of 8583 mA h g^?1 at a current density of 100 mA g^?1, a superior rate capacity of 6311 mA h g^?1 at 300 mA g^?1, and a very good cycling stability of 170 cycles at a current density of 200 mA g^?1 with a fixed capacity of 1000 mA h g^?1. Importantly, the presented design strategy of 3D hollow framework in this work could be extended to other catalytic cathode design for Li–O₂ batteries.     

Graphene Scroll‐Coated α‐MnO2 Nanowires as High‐Performance Cathode Materials for Aqueous Zn‐Ion Battery

The development of manganese dioxide as the cathode for aqueous Zn‐ion battery (ZIB) is limited by the rapid capacity fading and material dissolution. Here, a highly reversible aqueous ZIB using graphene scroll‐coated α‐MnO₂ as the cathode is proposed. The graphene scroll is uniformly coated on the MnO₂ nanowire with an average width of 5 nm, which increases the electrical conductivity of the MnO₂ nanowire and relieves the dissolution of the cathode material during cycling. An energy density of 406.6 Wh kg^?1 (382.2 mA h g^?1) at 0.3 A g^?1 can be reached, which is the highest specific energy value among all the cathode materials for aqueous Zn‐ion battery so far, and good long‐term cycling stability with 94% capacity retention after 3000 cycles at 3 A g^?1 are achieved. Meanwhile, a two‐step intercalation mechanism that Zn ions first insert into the layers and then the tunnels of MnO₂ framework is proved by in situ X‐ray diffraction, galvanostatic intermittent titration technique, and X‐ray photoelectron spectroscopy characterizations. The graphene scroll‐coated metallic oxide strategy can also bring intensive interests for other energy storage systems.