Delivery of antibacterial silver nanoclusters to Pseudomonas aeruginosa using species-specific DNA aptamers

Introduction. The use of silver as an antimicrobial therapeutic is limited by its toxicity to host cells compared with that required to kill bacterial pathogens.Aim. To use aptamer targeting of DNA scaffolded silver nanoclusters as an antimicrobial agent for treating Pseudomonas aeruginosa infections.Methodology. Antimicrobial activity was assessed in planktonic cultures and in vivo using an invertebrate model of infection.Results. The aptamer conjugates that we call aptabiotics have potent antimicrobial activity. Targeted silver nanoclusters were more effective at killing P. aeruginosa than the equivalent quantity of untargeted silver nanoclusters. The aptabiotics have an IC₅₀ of 1.3-2.6 µM against planktonically grown bacteria. Propidium iodide staining showed that they rapidly depolarize bacterial cells to kill approximately 50 % of the population within 10 min following treatment. In vivo testing in the Galleria mellonella model of infection prolonged survival from an otherwise lethal infection.Conclusion. Using P. aeruginosa as a model, we show that targeting of DNA-scaffolded silver nanoclusters with an aptamer has effective fast-acting antimicrobial activity in vitro and in an in vivo animal model.

Zinc-Ion-Induced Aggregation of Gold Clusters for Visible-Light-Excitation-Based Fluorimetric Discrimination of Geometrical Isomers

Herein, we report discrimination of dicarboxylic acids - fumaric acid (FA) and maleic acid (MA) - exhibiting geometrical isomerism, using nanoclusters based luminescent probe having excitation under broad day light. The luminescent probe was designed via complexation reaction between zinc ions and ligands (mercaptopropioinc acid; MPA) stabilizing the gold nanoclusters. This resulted in formation of nanoaggregates exhibiting bright green luminescence upon excitation at 450 nm capable of discriminating between FA and MA upto nanomolar level. The basis of discrimination has been attributed to deprotonation of FA and MA following interaction with MPA moieties present on the surface of the nanoaggregates and being governed by the stability of the respective conjugate base of the geometrical isomers of the dicarboxylic acids. As a consequence of different extent of deprotonation of FA and MA upon interaction with the cluster aggregates, different effect on the luminescence of the aggregates was observed, thus enabling discernible fluorimetric discrimination between FA and MA under visible light excitation.

Reactive Pulsed Laser Deposition of Clustered-Type MoSx (x ~ 2, 3, and 4) Films and Their Solid Lubricant Properties at Low Temperature

We studied the tribological properties of amorphous molybdenum sulfide (MoSx) thin-film coatings during sliding friction in an oxidizing environment at a low temperature (-100 °C). To obtain films with different sulfur contents (x ~ 2, 3, and 4), we used reactive pulsed laser deposition, where laser ablation of the Mo target was performed in H2S at various pressures. The lowest coefficient of friction (0.08) was observed during tribo-testing of the MoS3 coating. This coating had good ductility and low wear; the wear of a steel counterbody was minimal. The MoS2 coating had the best wear resistance, due to the tribo-film adhering well to the coating in the wear track. Tribo-modification of the MoS2 coating, however, caused a higher coefficient of friction (0.16) and the most intensive wear of the counterbody. The MoS4 coating had inferior tribological properties. This study explored the mechanisms of possible tribo-chemical changes and structural rearrangements in MoSx coatings upon contact with a counterbody when exposed to oxygen and water. The properties of the tribo-film and the efficiency of its transfer onto the coating and/or the counterbody largely depended on local atomic packing of the nanoclusters that formed the structure of the amorphous MoSx films.

Green and Sustainable Manufacture of Ultrapure Engineered Nanomaterials

Nanomaterials with very specific features (purity, colloidal stability, composition, size, shape, location…) are commonly requested by cutting-edge technologic applications, and hence a sustainable process for the mass-production of tunable/engineered nanomaterials would be desirable. Despite this, tuning nano-scale features when scaling-up the production of nanoparticles/nanomaterials has been considered the main technological barrier for the development of nanotechnology. Aimed at overcoming these challenging frontier, a new gas-phase reactor design providing a shorter residence time, and thus a faster quenching of nanoclusters growth, is proposed for the green, sustainable, versatile, cost-effective, and scalable manufacture of ultrapure engineered nanomaterials (ranging from nanoclusters and nanoalloys to engineered nanostructures) with a tunable degree of agglomeration, composition, size, shape, and location. This method enables: (1) more homogeneous, non-agglomerated ultrapure Au-Ag nanoalloys under 10 nm; (2) 3-nm non-agglomerated ultrapure Au nanoclusters with lower gas flow rates; (3) shape-controlled Ag NPs; and (4) stable Au and Ag engineered nanostructures: nanodisks, nanocrosses, and 3D nanopillars. In conclusion, this new approach paves the way for the green and sustainable mass-production of ultrapure engineered nanomaterials.

Development of Copper Nanoclusters for In Vitro and In Vivo Theranostic Applications

Theranostics refers to the incorporation of therapeutic and diagnostic functions into one material system. An important class of nanomaterials exploited for theranostics is metal nanoclusters (NCs). In contrast to gold and silver NCs, copper is an essential trace element for humans. It can be more easily removed from the body. This, along with the low cost of copper that offers potential large-scale nanotechnology applications, means that copper NCs have attracted great interest in recent years. The latest advances in the design, synthesis, surface engineering, and applications of copper NCs in disease diagnosis, monitoring, and treatment are reviewed. Strategies to control and enhance the emission of copper NCs are considered. With this synopsis of the up-to-date development of copper NCs as theranostic agents, it is hoped that insights and directions for translating current advances from the laboratory to the clinic can be further advanced and accelerated.

Visualization of Surface Plasmons Propagating at the Buried Organic/Metal Interface with Silver Nanocluster Sensitizers

Visualization of surface plasmon polariton (SPP) propagation at dielectric/metal interfaces is indispensable in providing opportunities for the precise designing and controlling of the functionalities of future plasmonic nanodevices. Here, we report the visualization of SPPs propagating along the buried organic/metal interface of fullerene (C₆₀)/Au(111), through dual-colored two-photon photoemission electron microscopy (2P-PEEM) which precisely visualizes the SPP propagation of plasmonic metal nanostructures. Although SPPs excited by near-infrared photons at the few monolayer C₆₀/Au(111) interface are clearly visualized as interference beat patterns between the SPPs and incident light, faithfully reflecting SPP properties modulated by the overlayer, photoemission signals are suppressed for thicker C₆₀ films, due to less valence electrons participating in 2P-photoemission processes. With the use of silver (Ag_n (n = 21 and 55)) nanoclusters, which exhibit enhancement of overall photoemission intensities due to localized surface plasmons functioning as SPP sensitizers, it is revealed that the 2P-PEEM is applicable to the imaging of SPPs for thick C₆₀/Au(111) interfaces, where SPP properties are hardly modulated by the added small amount (∼0.1 monolayer) of Ag_n sensitizers.

Preparation, Cytotoxicity, and In Vitro Bioimaging of Water Soluble and Highly Fluorescent Palladium Nanoclusters

Fluorescent probes offer great potential to identify and treat surgical tumors by clinicians. To this end, several molecular probes were examined as in vitro and in vivo bioimaging probes. However, due to their ultra-low extinction coefficients as well as photobleaching problems, conventional molecular probes limit its practical utility. To address the above mentioned challenges, metal nanoclusters (MNCs) can serve as an excellent alternative with many unique features such as higher molar extinction coefficients/light absorbing capabilities, good photostability and appreciable fluorescence quantum yields. Herein, we reported a green synthesis of water soluble palladium nanoclusters (Pd NCs) and characterized them by using various spectroscopic and microscopic characterization techniques. These nanoclusters showed excellent photophysical properties with the characteristic emission peak centered at 500 nm under 420 nm photoexcitation wavelength. In vitro cytotoxicity studies in human cervical cancer cells (HeLa) cells reveal that Pd NCs exhibited good biocompatibility with an IC₅₀ value of >100 µg/mL and also showed excellent co-localization and distribution throughout the cytoplasm region with a significant fraction translocating into cell nucleus. We foresee that Pd NCs will carry huge potential to serve as a new generation bioimaging nanoprobe owing to its smaller size, minimal cytotoxicity, nucleus translocation capability and good cell labelling properties.

Aptamer-Based Fluorescent Biosensing of Adenosine Triphosphate and Cytochrome c via Aggregation-Induced Emission Enhancement on Novel Label-Free DNA-Capped Silver Nanoclusters/Graphene Oxide Nanohybrids

Four fluorescent DNA-stabilized fluorescent silver nanoclusters (DNA-AgNCs) were designed and synthesized with differences in lengths of cytosine-rich DNA strand (as the stabilizing agent) and target-specific strand DNA aptamers for adenosine triphosphate (ATP) and cytochrome c (Cyt c). After their nanohybrid formation with graphene oxide (GO), it was unexpectedly found that, depending on the composition of the base and length of the strand DNA aptamer, the fluorescence intensity of three of the nanohybrids significantly enhanced. Our experimental observations and quantum mechanical calculations provided an insight into the mechanisms underlying the behavior of DNA-AgNCs/GO nanohybrids. The enhanced fluorescence was found to be attributed to the aggregation-induced emission enhancement (AIE) characteristic of the DNA-AgNCs adsorbed on the GO surface, as confirmed evidently by both fluorescence and transmission electron microscopies. The AIE is a result of hardness and oxidation properties of GO, which lead to enhanced argenophilic interaction and thus to increased Ag(I)-DNA complex shell aggregation. Consequently, two of the DNA-AgNCs/GO nanohybrids were successfully extended to construct highly selective, sensitive, label-free, and simple aptasensors for biosensing of ATP (LOD = 0.42 nM) and Cyt c (LOD = 2.3 nM) in lysed Escherichia coli DH5 α cells and mouse embryonic stem cells, respectively. These fundamental findings are expected to significantly influence the designing and engineering of new AgNCs/GO-based AIE biosensors.

Tuning of 2D Nanographene Adlayers on Au(111) by Electrodeposition of Metal Halide Complexes

The electrodeposition of AuBr₄^- and PtBr₄^2- onto an adlayer of circobiphenyl-a structurally defined nanographene with low symmetry-on a Au(111) electrode was investigated via electrochemical scanning tunneling microscopy (EC-STM) to control and understand the formation of characteristic nanoclusters. By immersing a circobiphenyl-coated Au(111) substrate in a 0.1 mM aqueous AuBr₄^- solution, AuBr₄^- was spontaneously reduced, and a characteristic mixed adlayer consisting of circobiphenyl molecules and Br^- ions with monatomic Au islands was produced on the Au(111) surface. A similar electrodeposition process was performed in an aqueous solution of PtBr₄^2-, and an identical mixed adlayer was obtained with Pt nanoclusters. The electrodeposition of Au and Pt complexes was facilitated by the "negatively charged" reconstructed Au(111) surface, which is stabilized by the formation of a highly ordered circobiphenyl adlayer. EC-STM revealed the formation of characteristic dimers of Pt clusters ranging 2-4 nm in diameter on the circobiphenyl adlayer. Thus, Br^- metal complexes were found to play an important role in controlling the structure and size of a mixed adlayer containing Br^- and the shape of Pt clusters.

Interparticle Reactions between Silver Nanoclusters Leading to Product Cocrystals by Selective Cocrystallization

We present an example of an interparticle reaction between atomically precise nanoclusters (NCs) of the same metal, resulting in entirely different clusters. In detail, the clusters [Ag₁₂(TBT)₈(TFA)₅(CH₃CN)]⁺ (TBT = tert-butylthiolate, TFA = trifluoroacetate, CH₃CN = acetonitrile) and [Ag₁₈(TPP)₁₀H₁₆]²⁺ (TPP = triphenylphosphine) abbreviated as Ag₁₂ and Ag₁₈, respectively, react leading to [Ag₁₆(TBT)₈(TFA)₇(CH₃CN)₃Cl]⁺ and [Ag₁₇(TBT)₈(TFA)₇(CH₃CN)₃Cl]⁺, abbreviated as Ag₁₆ and Ag₁₇, respectively. The two product NCs crystallize together as both possess the same metal chalcogenolate shell, composed of Ag₁₆S₈, making them indistinguishable. The occupancies of Ag₁₆ and Ag₁₇ are 66.66 and 33.33%, respectively, in a single crystal. Electrospray ionization mass spectrometry (ESI MS) of the reaction product and a dissolved crystal show the population of Ag₁₆ and Ag₁₇ NCs to be in a 1:1 and 2:1 ratio, respectively. This suggests selective crystallization in the cocrystal. Time-dependent ESI MS was employed to understand the formation of product clusters by monitoring the reaction intermediates formed in the course of the reaction. We present an unprecedented growth mechanism for the formation of silver NCs mediated by silver thiolate intermediates.

In Situ Observation of Metal to Metal Oxide Progression: A Study of Charge Transfer Phenomenon at Ru-CuO Interfaces

Surface charge and charge transfer between nanoclusters and oxide supports are of paramount importance to catalysis, surface plasmonics, and optical energy harvesting areas. At present, high-energy X-rays and theoretical investigation are always required to determine the chemical state changes in the nanoclusters and the oxide supports, as well as the underlying transfer charge between them. This work presents the idea of using chrono-conductometric measurements to determine the chemical states of the Ru nanoclusters on CuO supports. Both icosahedral and single-crystal hexagonal close-packed Ru nanoclusters were deposited through gas-phase synthesis. To study the charge transfer phenomenon at the interface, a bias was applied to cupric oxide nanowires with metallic nanocluster decoration. In situ conductometric measurements were performed to observe the evolution of Ru into RuO_x under heating conditions. Structural elucidation techniques such as transmission electron microscopy, X-ray photoelectron spectroscopy, and Kelvin probe force microscopy were employed to study the corresponding progression of structure, chemical ordering, and surface potential, respectively, as Ru(0) was oxidized to RuO_x on the supporting oxide surface. Experimental and theoretical investigation of charge transfer between the nanocluster and oxide support highlighted the importance of metallic character and structure of the nanoclusters on the interfacial charge transfer, thus allowing the investigation of surface charge behavior on oxide-supported catalysts, in situ, during catalytic operation via conductometric measurements.

Structure and Properties of Nanosilicates with Olivine (Mg2SiO4) N and Pyroxene (MgSiO3) N Compositions

Magnesium-rich silicates are ubiquitous both terrestrially and astronomically, where they are often present as small particles. Nanosized Mg-rich silicate particles are likely to be particularly important for understanding the formation, processing, and properties of cosmic dust grains. Although astronomical observations and laboratory studies have revealed much about such silicate dust, our knowledge of this hugely important class of nanosolids largely rests on top-down comparisons with the properties of bulk silicates. Herein, we provide a foundational bottom-up study of the structure and properties of Mg-rich nanosilicates based on carefully procured atomistic models. Specifically, we employ state-of-the-art global optimization methods to search for the most stable structures of silicate nanoclusters with olivine (Mg₂SiO₄) _N and pyroxene (MgSiO₃) _N compositions with N = 1-10. To ensure the reliability of our searches, we develop a new interatomic potential that has been especially tuned for nanosilicates. Subsequently, we refine these searches and calculate a range of physicochemical properties of the most stable nanoclusters using accurate density functional theory based electronic structure calculations. We report a detailed analysis of structural and energy properties, charge distributions, and infrared vibrational spectra, where in all cases we compare our finding for nanosilicates with those of the corresponding bulk silicate crystals. For most properties considered, we find large differences with respect to the bulk limit, underlining the limitations of a top-down approach for describing these species. Overall, our work provides a new platform for an accurate and detailed understanding of nanoscale silicates.

Confinement-Induced Giant Spin-Orbit-Coupled Magnetic Moment of Co Nanoclusters in TiO2 Films

High magnetization materials are in great demand for the fabrication of advanced multifunctional magnetic devices. Notwithstanding this demand, the development of new materials with these attributes has been relatively slow. In this work, we propose a new strategy to achieve high magnetic moments above room temperature. Our material engineering approach invoked the embedding of magnetic nanoclusters in an oxide matrix. By precisely controlling pulsed laser deposition parameters, Co nanoclusters are formed in a 5 at % Co-TiO₂ film. The presence of these nanoclusters was confirmed using transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray absorption fine structure. The film exhibits a very high saturation magnetization of 99 emu/cm³. Detailed studies using X-ray magnetic circular dichroism confirm that Co has an enhanced magnetic moment of 3.5 μ_B/atom, while the Ti and O also contribute to the magnetic moments. First-principles calculations supported our hypothesis that the metallic Co nanoclusters surrounded by a TiO₂ matrix can exhibit both large spin and orbital moments. Moreover, a quantum confinement effect results in a high Curie temperature for the embedded Co nanoclusters. These findings reveal that 1-2 nm nanoclusters that are quantum confined can exhibit very large magnetic moments above room temperature, representing a promising advance for the design of new high magnetization materials.

DNA-Templated Fluorescent Nanoclusters for Metal Ions Detection

DNA-templated fluorescent nanoclusters (NCs) have attracted increasing research interest on account of their prominent features, such as DNA sequence-dependent fluorescence, easy functionalization, wide availability, water solubility, and excellent biocompatibility. Coupling DNA templates with complementary DNA, aptamers, G-quadruplex, and so on has generated a large number of sensors. Additionally, the preparation and applications of DNA-templated fluorescent NCs in these sensing have been widely studied. This review firstly focuses on the properties of DNA-templated fluorescent NCs, and the synthesis of DNA-templated fluorescent NCs with different metals is then discussed. In the third part, we mainly introduce the applications of DNA-templated fluorescent NCs for sensing metal ions. At last, we further discuss the future perspectives of DNA-templated fluorescent NCs in the synthesis and sensing metal ions in the environmental and biological fields.

Renal clearable catalytic gold nanoclusters for in vivo disease monitoring

Ultrasmall gold nanoclusters (AuNCs) have emerged as agile probes for in vivo imaging, as they exhibit exceptional tumour accumulation and efficient renal clearance properties. However, their intrinsic catalytic activity, which can enable an increased detection sensitivity, has yet to be explored for in vivo sensing. By exploiting the peroxidase-mimicking activity of AuNCs and the precise nanometre-size filtration of the kidney, we designed multifunctional protease nanosensors that respond to disease microenvironments to produce a direct colorimetric urinary readout of the disease state in less than one hour. We monitored the catalytic activity of AuNCs in the collected urine of a mouse model of colorectal cancer in which tumour-bearing mice showed a 13-fold increase in colorimetric signal compared to healthy mice. The nanosensors were eliminated completely through hepatic and renal excretion within four weeks of injection with no evidence of toxicity. We envision that this modular approach will enable the rapid detection of a diverse range of diseases by exploiting their specific enzymatic signatures.

Ultrafast, Controllable Synthesis of Sub-Nano Metallic Clusters through Defect Engineering

Supported metallic nanoclusters (NCs, < 2 nm) are of great interests in various catalytic reactions with enhanced activities and selectivities, yet it is still challenging to efficiently and controllably synthesize ultrasmall NCs with a high-dispersal density. Here we report the in situ synthesis of surfactant-free, ultrasmall, and uniform NCs via a rapid thermal shock on defective substrates. This is achieved by using high-temperature synthesis with extremely fast kinetics while limiting the synthesis time down to milliseconds (e.g., ∼1800 K for 55 ms) to avoid aggregation. Through defect engineering and optimized loading, the particle size can be robustly tuned from >50 nm nanoparticles to <1 nm uniform NCs with a high-dispersal density. We demonstrate that the ultrasmall NCs exhibit drastically improved activities for catalytic CO oxidation as compared to their nanoparticulated counterparts. In addition, the reported method shows generality in synthesizing most metallic NCs (e.g., Pt, Ru, Ir, Ni) in an extremely facile and efficient manner. The ultrafast and controllable synthesis of uniform, high-density, and size-controllable NCs paves the way for the utilization and nanomanufacturing of NCs for a range of catalytic reactions.

Selective Hydrogenation of CO2 Dictated by Isomers in Au28 (SR)20 Nanoclusters: Which One is Better?

It is a challenge to make clear how isomerism in a heterogeneous catalyst induces distinct differences in catalytic properties, as attainment of the structural isomerism in a conventional catalyst is difficult. By successfully identifying the isomerism in the atomically precise Au nanoclusters, an exciting opportunity for unravelling catalysis of isomeric catalysts is opened up. Herein, we report that the isomerism in the Au₂₈ (SR)₂₀ nanoclusters with different surface atom arrangements can indeed render different catalytic behaviors in the selective hydrogenation of CO₂ . We anticipate that our studies will serve as a starting point for fundamental investigations about how to control the catalytic activity and selectivity by the isomerism-induced catalysis.

Silver Nanoclusters Encapsulated into Metal-Organic Frameworks for Rapid Removal of Heavy Metal Ions from Water

Metal nanomaterials have been reported as effective absorbents for the removal of pollutants in the water system, but the release of ions from these nanomaterials brings another concern. Herein, silver nanoclusters (AgNCs) were encapsulated in porous metal-organic frameworks of ZIF-8 (MOF-AgNCs). Compared to AgNCs, the release of Ag⁺ significantly decreases from MOF-AgNCs, indicating that the product presents a lower threat to the environment. The MOF-AgNCs were employed for the rapid removal of heavy metals, such as Pb²⁺ and Mn²⁺, from water. The mechanism and removal efficiencies were investigated.

The Ligand-Exchange Reactions of Rod-Like Au25-n Mn (M=Au, Ag, Cu, Pd, Pt) Nanoclusters with Cysteine - A Density Functional Theory Study

The atomic precision of ultrasmall noble-metal nanoclusters (NMNs) is fundamental for elucidating structure-property relationships and probing their practical applications. So far, the atomic structure of NMNs protected by organic ligands has been widely elucidated, whereas the precise atomic structure of NMNs protected by water-soluble ligands (such as peptides and nucleic acid), has been rarely reported. With the concept of "precision to precision", density functional theory (DFT) calculations were performed to probe the thermodynamic plausibility and inherent determinants for synthesizing atomically precise, water-soluble NMNs via the framework-maintained two-phase ligand-exchange method. A series of rod-like Au_25-n M_n (M=Au, Ag, Cu, Pd, Pt) NMNs with the same framework but varied ligands and metal compositions was chosen as the modeling reactants, and cysteine was used as the modeling water-soluble ligand. It was found that the acidity of the reaction remarkably affects the thermodynamic facility of the ligand exchange reactions. Ligand effects (structural distortion and acidity) dominate the overall thermodynamic facility of the ligand-exchange reaction, while the number and type of doped metal atom(s) has little influence.

Frontotemporal dementia mutant Tau promotes aberrant Fyn nanoclustering in hippocampal dendritic spines

The Src kinase Fyn plays critical roles in memory formation and Alzheimer’s disease. Its targeting to neuronal dendrites is regulated by Tau via an unknown mechanism. As nanoclustering is essential for efficient signaling, we used single-molecule tracking to characterize the nanoscale distribution of Fyn in mouse hippocampal neurons, and manipulated the expression of Tau to test whether it controls Fyn nanoscale organization. We found that dendritic Fyn exhibits at least three distinct motion states, two of them associated with nanodomains. Fyn mobility decreases in dendrites during neuronal maturation, suggesting a dynamic synaptic reorganization. Removing Tau increases Fyn mobility in dendritic shafts, an effect that is rescued by re-expressing wildtype Tau. By contrast, expression of frontotemporal dementia P301L mutant Tau immobilizes Fyn in dendritic spines, affecting its motion state distribution and nanoclustering. Tau therefore controls the nanoscale organization of Fyn in dendrites, with the pathological Tau P301L mutation potentially contributing to synaptic dysfunction by promoting aberrant Fyn nanoclustering in spines.

Biocompatible Nanoclusters with High Heating Efficiency for Systemically Delivered Magnetic Hyperthermia

Despite its promising therapeutic potential, nanoparticle-mediated magnetic hyperthermia is currently limited to the treatment of localized and relatively accessible cancer tumors because the required therapeutic temperatures above 40 °C can only be achieved by direct intratumoral injection of conventional iron oxide nanoparticles. To realize the true potential of magnetic hyperthermia for cancer treatment, there is an unmet need for nanoparticles with high heating capacity that can efficiently accumulate at tumor sites following systemic administration and generate desirable intratumoral temperatures upon exposure to an alternating magnetic field (AMF). Although there have been many attempts to develop the desired nanoparticles, reported animal studies reveal the challenges associated with reaching therapeutically relevant intratumoral temperatures following systemic administration at clinically relevant doses. Therefore, we developed efficient magnetic nanoclusters with enhanced heating efficiency for systemically delivered magnetic hyperthermia that are composed of cobalt- and manganese-doped, hexagon-shaped iron oxide nanoparticles (CoMn-IONP) encapsulated in biocompatible PEG-PCL (poly(ethylene glycol)- b-poly(ε-caprolactone))-based nanocarriers. Animal studies validated that the developed nanoclusters are nontoxic, efficiently accumulate in ovarian cancer tumors following a single intravenous injection, and elevate intratumoral temperature up to 44 °C upon exposure to safe and tolerable AMF. Moreover, the obtained results confirmed the efficiency of the nanoclusters to generate the required intratumoral temperature after repeated injections and demonstrated that nanocluster-mediated magnetic hyperthermia significantly inhibits cancer growth. In summary, this nanoplatform is a milestone in the development of systemically delivered magnetic hyperthermia for the treatment of cancer tumors that are difficult to access for intratumoral injection.

Amphipathic Nanodiamond Supraparticles for Anticancer Drug Loading and Delivery

Nanodiamonds (NDs) have been attracting considerable attention due to their outstanding chemical, physical, and physiological properties. Additional functionalization of NDs can be carried out by the self-assembly technique. This study reports a straightforward chemical route for self-assembled supraparticles (SPs) based on ND (ND-SPs) using alkyl carboxylic acids with different aliphatic alkyl chain lengths by carbodiimide chemistry and sonication. Poly(ethylene glycol) (PEG)-modified ND-SPs are synthesized successfully for effective nanodrug formulations with the hydrophobic anticancer drug paclitaxel (PTX). The properties of these ND-SP nanomedicines are investigated thoroughly by complementary analytical, spectroscopic, and microscopic techniques. This simple methodology permitted the application of PEG-modified ND-SP-encapsulating PTX as a potent drug carrier, achieving greater efficacy than commercial Abraxane. Results revealed that the morphology, particle size, and water dispersibility of the prepared ND-SP nanoclusters affect the drug efficacy. These PEG-modified ND-SP nanoclusters serve as novel nanomedicine for a passive drug delivery system as well as anticancer chemotherapy.

Integrin Mechano-chemical Signaling Generates Plasma Membrane Nanodomains that Promote Cell Spreading

Glycosylphosphatidylinositol-anchored proteins (GPI-APs) are a major class of lipid-anchored plasma membrane proteins. GPI-APs form nanoclusters generated by cortical acto-myosin activity. While our understanding of the physical principles governing this process is emerging, the molecular machinery and functional relevance of GPI-AP nanoclustering are unknown. Here, we first show that a membrane receptor signaling pathway directs nanocluster formation. Arg-Gly-Asp motif-containing ligands bound to the β1-integrin receptor activate src and focal adhesion kinases, resulting in RhoA signaling. This cascade triggers actin-nucleation via specific formins, which, along with myosin activity, drive the nanoclustering of membrane proteins with actin-binding domains. Concurrently, talin-mediated activation of the mechano-transducer vinculin is required for the coupling of the acto-myosin machinery to inner-leaflet lipids, thereby generating GPI-AP nanoclusters. Second, we show that these nanoclusters are functional; disruption of their formation either in GPI-anchor remodeling mutants or in vinculin mutants impairs cell spreading and migration, hallmarks of integrin function.

Aggregation-Induced Electrochemiluminescence by Metal-Binding Protein Responsive Hydrogel Scaffolds

Functionalized hydrogels have aroused general interest due to their versatile applications in biomaterial fields. This work reports a hydrogel network composed of gold nanoclusters linked with bivalent cations such as Ca²⁺ , Mg²⁺ , and Zn²⁺ . The hydrogel exhibits both aggregation-induced emission (AIE) and aggregation-induced electrochemiluminescence (AIECL) effects. Most noteworthy, the AIECL effect (≈50-fold enhancement) is even more significant than the corresponding AIE effect (approximately fivefold enhancement). Calmodulin, a Ca²⁺ binding protein, may efficiently regulate the AIECL dynamics after specific binding of the Ca²⁺ linker, with the linear range from 0.3 to 50 µg mL^-1 and a limit of detection of 0.1 µg mL^-1 . Considering the important roles of bivalent cations in the life system, these results may pave a new avenue for the design of a biomolecule-responsive AIECL-type hydrogel with multifunctional biomedical purposes.

Anion Dependent Self-Assembly of Polynuclear Cd-Ln Schiff Base Nanoclusters: NIR Luminescent Sensing of Nitro Explosives

Two types of polynuclear Cd-Ln complexes [CdLnL(NO₃)Cl₂(DMF)₂] [Ln = La (1) and Nd (2)] and [Ln₂CdL₂(NO₃)₂(DMF)₂](OH)₂ [Ln = La (3) and Nd (4)] were constructed using a new Schiff base ligand which has a long backbone with two phenyl groups. The Schiff base ligands show a "twist" configuration in 1-4. The crystal structures show that the molecular dimensions of 3 and 4 are about 6 × 10 × 15 Å. The Cd-Nd complexes 2 and 4 exhibit the typical NIR luminescence of Nd³⁺. Interestingly, 4 shows the luminescent sensing of nitro explosives and exhibits a high sensitivity to 2-nitrophenol at the ppm level.