Self-assembled Metal Research Articles

Enhanced Sonodynamic Therapy for Deep Tumors Using a Self-Assembled Organoplatinum(II) Sonosensitizer.

Despite the promising advances in photodynamic therapy (PDT), it remains challenging to target and treat deep-seated solid tumors effectively. Herein, we developed an organoplatinum(II) complex (Pt-TPE) with self-assembly properties for sonodynamic therapy (SDT). Pt-TPE forms a nanofiber network structure through Pt-Pt and π-π stacking interactions. Notably, under ultrasound (US), Pt-TPE demonstrates unique self-assembly-induced singlet oxygen (1O2) generation due to a significantly enhanced singlet-triplet intersystem crossing (ISC). This generation of 1O2 occurs exclusively in the self-assembled state of Pt-TPE. Additionally, Pt-TPE exhibits sono-cytotoxicity against cancer cells by impairing mitochondrial membrane potential (MMP), inhibiting glucose uptake, and aerobic glycolysis. Furthermore, US-activated Pt-TPE significantly inhibits deep solid tumors in mice, achieving remarkable therapeutic efficacy even at penetration depths greater than 10 cm. This study highlights the potential of self-assembled metal complexes to enhance the efficacy of SDT for treating deep tumors.

Hydroxyl-driven construction of dual-emitting CsPbBr3/EuWO4(OH) composite for radiometric thermometer and information encryption applications

Self-assembled inorganic metal halide perovskite composites with high emitting efficiency, tunable multimode emission and stimuli-responsive luminescence demonstrated great potential in diversified luminescence applications. Here, a novel CsPbBr3/EuWO4(OH) composite was successfully prepared through the surface adsorption of Pb2+ ions on hydroxylated EuWO4(OH) microsheets and subsequent nucleation of CsPbBr3 peroviskite quantum dots (PQDs) by the anti-solvent crystallization in CsBr containing N,N-dimethylformamide (DMF) solution. Due to the distinct fluorescent thermochromic switching properties of temperature-insensitive Eu3+ and sensitive CsPbBr3 PQDs emitting centers, the resultant CsPbBr3/EuWO4(OH) composite exhibits excellent ratiometric temperature sensing performance. The CsPbBr3/EuWO4(OH) thermometer based on the fluorescence intensity ratio (FIR) technique originating from emissions of Eu3+ to CsPbBr3 PQDs was then explored with a high temperature sensitivity (Sr) of 5.8 % ℃−1 at 54 ℃. In addition, a high-security-level information encryption scheme was proposed by utilizing the excitation-wavelength-dependent switchable fluorescence of CsPbBr3/EuWO4(OH) composite. This study provides a simple and feasible strategy for assembling dual-emission CsPbBr3/EuWO4(OH) composite, showing potential applications in optical ratiometric thermometry and information encryption fields.

Recent Advances in Research from Nanoparticle to Nano-Assembly: A Review.

The careful arrangement of nanomaterials (NMs) holds promise for revolutionizing various fields, from electronics and biosensing to medicine and optics. This review delves into the intricacies of nano-assembly (NA) techniques, focusing on oriented-assembly methodologies and stimuli-dependent approaches. The introduction provides a comprehensive overview of the significance and potential applications of NA, setting the stage for review. The oriented-assembly section elucidates methodologies for the precise alignment and organization of NMs, crucial for achieving desired functionalities. The subsequent section delves into stimuli-dependent techniques, categorizing them into chemical and physical stimuli-based approaches. Chemical stimuli-based self-assembly methods, including solvent, acid-base, biomolecule, metal ion, and gas-induced assembly, are discussed in detail by presenting examples. Additionally, physical stimuli such as light, magnetic fields, electric fields, and temperature are examined for their role in driving self-assembly processes. Looking ahead, the review outlines futuristic scopes and perspectives in NA, highlighting emerging trends and potential breakthroughs. Finally, concluding remarks summarize key findings and underscore the significance of NA in shaping future technologies. This comprehensive review serves as a valuable resource for researchers and practitioners, offering insights into the diverse methodologies and potential applications of NA in interdisciplinary research fields.

Numerical investigation of dynamic plasmonic color generated via photothermal deformation of a metal semi-shell structure

Dyes and pigments for coloring have issues such as fading, stability at high temperatures, and submicron coloration. To solve these issues and realize a coloring method that is easily applicable to larger areas at a lower cost, we study plasmonic coloring using dynamic wavelength tuning via photothermal deformation of self-assembled metal semi-shell nanoparticles. Using discrete dipole approximation on a nanoparticle with a photothermally deformable metal semi-shell, we construct chromaticity diagrams for various substrate materials, semi-shell materials, and nanoparticle densities as well as present the possibility of achieving a wide color gamut by plasmonic coloration.

Self-assembly metal phenolic network coating improves the controlled release and bacteriostatic properties of Litsea cubeba essential oil-loaded ε-polylysine-pectin nanoparticles

Pectin and ε-polylysine (ε-PL) nanoparticles loaded with Litsea cubeba essential oil (LEO) (PP-LNPs) were prepared through the electrostatic interaction. Metal phenol network (MPN) coatings, designated as MPN@PP-LNPs, were fabricated on the surface of the nanoparticles via self-assembly process of tannic acid (TA) and FeIII to develop food preservative materials with pH-responsive controlled release. The morphology, encapsulation efficiency, and pH-responsive release characteristics of MPN@PP-LNPs were investigated. The results showed that the particle size of MPN@PP-LNPs was 432.5 ± 58.6 nm. Furthermore, the encapsulation efficiencies of ε-PL and LEO were 83.26 ± 2.21% and 30.78 ± 3.92%, respectively. TA was rapidly released at low pH, while LEO exhibited controlled release over a wide pH range (pH 1.2–9.0). In addition, the MPN coating has been demonstrated to enhance antioxidant activity and inhibit the growth of E. coli and S. aureus under acidic conditions. Furthermore, preliminary evidence suggests that MPN@PP-LNPs are not cytotoxic. In conclusion, MPN@PP-LNPs, prepared through the self-assembled surface modification of TA and FeIII, was an effective material for food preservation.

An intelligent and self-assembled nanoscale metal organic framework (99mTC-DOX loaded Fe3O4@FeIII-tannic acid) for tumor targeted chemo/chemodynamic theranostics

BackgroundRecent advances in clinical transformation research have focused on chemodynamic theranostics as an emerging strategy for tackling cancer. Nevertheless, its effectiveness is hampered by the tumor's glutathione antioxidant effect, poor acidic tumor microenvironment (TME) and inadequate endogenous H2O2. Hence, we designed an activatable theranostics (99mTc-DOX loaded AA-Fe3O4@FeIII-TA) that effectively boost the catalytic efficiency of the Fenton-reaction-induced ROS production and augment the chemotherapeutic efficacy combined with diagnostic action.ResultsA cross-linked matrix of tannic acid-ferric salt (FeIII-TA) as a pH-responsive shell onto ascorbic acid-decorated iron-oxide nanoparticles (AA-Fe3O4NPs) was prepared demonstrating a metal–organic- framework (MOF) nanostructure, followed by loading of 99mTc-labelled DOX. The platform (99mTc-DOX loaded AA-Fe3O4@FeIII-TA) displayed suitable physical–chemical properties, including 69.8 nm particle size, 94.8 nm hydrodynamic size, − 21 mV zeta potential, effective FeIII-TA shell crosslinking onto AA-Fe3O4NPs and 94% loading efficiency for 99mTc-DOX. The results of the in-vitro release investigations showed that the platform exhibited a pH-dependent release manner with 98.3% of the 99mTc-DOX being released at pH 5 (simulating the tumor’s pH) and only 10% being released at the physiological pH (pH 7.4). This indicates that there was negligible payload leakage into the systemic circulation during the platform's passive accumulation inside tumor. Due to the acidic TME nature, the MOF shell might be degraded releasing free FeIII, TA and a sustained release of 99mTc-DOX. Besides its chemotherapeutic impact and capacity to raise intracellular H2O2 content, the released 99mTc-DOX might be used as SPECT imaging tracer for concurrent tumor diagnosis. Furthermore, the mild acidity of the tumor may be overcome by the released TA, which might raise the acidification level of cancer cells. The released FeIII, TA and the endogenous GSH could engage in a redox reaction that depletes GSH and reduces FeIII to FeII ions which subsequently catalyze the elevated concentration of H2O2 to reactive •OH via Fenton-like reaction, increasing the effectiveness of chemodynamic therapy. Moreover, the in-vivo evaluation in tumor-bearing mice showed significant radioactivity accumulation in the tumor lesion (16.8%ID/g at 1 h post-injection) with a potential target/non-target ratio of 8.ConclusionsThe 99mTc-DOX loaded AA-Fe3O4@FeIII-TA could be introduced as an effective chemo/chemodynamic theranostics.Graphical

Cell membrane-inspired self-assembly corrosion resistant liquid metal composite coating with photothermal/electrothermal anti-icing/de-icing performance

Liquid metals have been expected to be promising photothermal/electrothermal anti-icing materials for their excellent electrical and thermal conductivity. However, inescapable oxidation and corrosion limit the life and efficiency of liquid metal materials. Inspired by the self-assembly of phospholipid molecules in cell membranes, self-assembly corrosion resistant liquid metal composite coating is designed to protect liquid metal from icing and corrosion hazards. Based on self-assembly of fluor‑silicon molecules mimicking phospholipid molecules and micro-nano surface morphology, the coating has water contact angle of 150.8°and icing delay time of 497 s, which is 4.21 times that of unmodified liquid metal. Under the combined action of 80.5 °C photothermal effect and superhydrophobicity, the de-icing efficiency of the coating is 2.04 times that of the unmodified liquid metal. The photothermal de-icing efficiency remains 99.3 % after two months of acid corrosion and 94.4 % after two months of alkali corrosion. In addition, the thermal network of the coating leads to thermal conductivity of 3.66 W/mK and flame retardancy with UL94 at V0 rating. The coating is made into an electrothermal device with 52.5 °C heating temperature and rapidly de-icing property. The cell membrane-inspired self-assembly liquid metal composite coating provides a secure solution for long-term photothermal/electrothermal anti-icing/de-icing in exposed environment.

Robust Low-Friction and Low-Wear TiNbMoTaCr High-Entropy Film Enabled by Periodically Inserting Curved MoS2 Sheets.

The well-known integration of physical, chemical, and mechanical properties enables high-entropy alloys (HEAs) to be applied in various fields; however, refractory HEAs are brittle and susceptible to abrasive wear at high coefficients of friction (COF), resulting in insufficient mechanical durability against abrasion. Herein, curved MoS2 nanosheets are periodically introduced into the TiNbMoTaCr film for triggering the self-assembly mixed metal oxides @MoS2 nanoscrolls, which contain hard mixed metal oxides cores and the low-shearing lubricant MoS2 shells, during the friction in the air environment; such mixed metal oxides@MoS2 nanoscrolls in the friction interfaces can contribute to the robust low friction and low wear. Compared to the pure TiNbMoTaCr film (with high COF of ∼0.78, low abrasive durability identified by worn-out event), the periodic incorporation of 10 nm thickness curved MoS2 sheets can successfully achieve a low COF of ∼0.08 and low wear rate of ∼9.561 × 10-8 mm3/ Nm, much lower than the pure MoS2 film (COF = ∼ 0.21, wear rate = ∼ 1.03 × 10-6 mm3/ Nm). Such superior tribological properties originate from the cooperative interaction of TiNbMoTaCr nanolayers and curved MoS2 nanosheets, accompanied by the self-assembly of mixed metal oxides@MoS2 nanoscrolls. In these nanoscrolls, TiNbMoTaCr can act as an 'air-absorbing agent' to form high-loading mixed metal oxide cores and serve as an 'oxygen sacrificer,' preventing the low-shearing lubricant curved MoS2 nanosheets from oxidation. In addition, even with the soft MoS2, the hardness of the TiNbMoTaCr/MoS2 nanomultilayers can still be well maintained and increased above the calculated values by mixing law, further favoring superior mechanical durability. The synergetic effect of TiNbMoTaCr and curved MoS2 nanosheets during the friction in air can provide a route to design HEA films with enhanced tribological properties for better mechanical durability and broader application prospects.

Tracing the genealogy of research on the mechanism of blue flower coloration by anthocyanin based on Keita Shibata's work.

K. Shibata is the ancestor of the research on anthocyanins in Japan and proposed metal complex theory against the pH theory by R. Willstätter. Shibata's successors, S. Hattori and K. Hayashi, made efforts to clarify blue flower coloration by metal complexation and found commelinin, a self-assembled supramolecular metal complex pigment, in blue dayflower, Tsuyukusa. The author introduces two key reports on blue flower coloration published in the Proceedings of the Japan Academy and describes the subsequent development of the study.

High-order layered self-assembled multicavity metal--organic capsules and anti-cooperative host-multi-guest chemistry.

The construction and application of metal-organic cages with accessible internal cavities have witnessed rapid development, however, the precise synthesis of complex metal-organic capsules with multiple cavities and achievement of multi-guest encapsulation, and further in-depth comprehension of host-multi-guest recognition remain a great challenge. Just like building LEGO blocks, herein, we have constructed a series of high-order layered metal-organic architectures of generation n (n = 1/2/3/4 is also the number of cavities) by multi-component coordination-driven self-assembly using porphyrin-containing tetrapodal ligands (like plates), multiple parallel-podal ligands (like clamps) and metal ions (like nodes). Importantly, these high-order assembled structures possessed different numbers of rigid and separate cavities formed by overlapped porphyrin planes with specific gaps. The host-guest experiments and convincing characterization proved that these capsules G2-G4 could serve as host structures to achieve multi-guest recognition and unprecedentedly encapsulate up to four C60 molecules. More interestingly, these capsules revealed negative cooperation behavior in the process of multi-guest recognition, which provides a new platform to further study complicated host-multi-guest interaction in the field of supramolecular chemistry.

Self-assembled two-dimensional metal–organic framework membranes as nanofluidic osmotic power generators

2D ZnTCPP membranes with nanopores of 1.2 nm and interlayer spacing of 0.9 nm exhibit excellent osmotic power generation.

A self-assembled metal–organic framework for enhanced UO22+ fluorescence sensing: integration of an octa-nuclear zinc cluster with hexakis(4-carboxyphenoxy)cyclotriphosphazene

A novel photoactive Zn-MOF was successfully synthesised by introducing a flexible cyclotriphosphonitrile hexacarboxylic acid, which achieves a sensitive fluorescence quenching response to radioactive UO22+ ions and the heavy metal Fe3+.

Rapid self-assembly of self-healable and transferable liquid metal epidermis

Healable electronic skins, an essential component for future soft robotics, implantable bioelectronics, and smart wearable systems, necessitate self-healable and pliable materials that exhibit functionality at intricate interfaces. Although a plethora of self-healable materials have been developed, the fabrication of highly conformal biocompatible functional materials on complex biological surfaces remains a formidable challenge. Inspired by regenerative properties of skin, we present the self-assembled transfer-printable liquid metal epidermis (SALME), which possesses autonomous self-healing capabilities at the oil–water interface. SALME comprises a layer of surfactant-grafted liquid metal nanodroplets that spontaneously assemble at the oil–water interface within a few seconds. This unique self-assembly property facilitates rapid restoration (<10 s) of SALME following mechanical damage. In addition to its self-healing ability, SALME exhibits excellent shear resistance and can be seamlessly transferred to arbitrary hydrophilic/hydrophobic curved surfaces. The transferred SALME effectively preserves submicron-scale surface textures on biological substrates, thus displaying tremendous potential for future epidermal bioelectronics.

Multifunctional Chiral d10-Metal Coordination Polymers: Tunable Photoluminescence and Efficient Second-Harmonic Generation with Circular Dichroic Response.

A series of homochiral coordination polymers (HCPs), [M2(SIAP)2(bpy)2] [M(S)] and [M2(RIAP)2(bpy)2] [M(R)] (M = Zn or Cd, SIAP or RIAP = (S,S)- or (R,R)- 2,2'-(isophthaloylbis(azanediyl))di-propionic acid, bpy = 4,4'-bipyridine), is successfully synthesized through solvothermal reactions, self-assembling d10 metal cations, chiral dicarboxylic ligands, and π-conjugated bipyridyl ligands. The HCPs crystallize in the extremely rare triclinic chiral space group, P1, and present 3D framework structures attributed to the strong intermolecular interactions, such as hydrogen bonds and π-π stacking. Due to the unique crystal structures, the title compounds reveal efficient photoluminescence emission across a broad visible range, with significant brightness and color tuning by varying the excitation wavelength. Moreover, they exhibit efficient phase-matched second-harmonic generation (SHG) with very high laser-induced damage thresholds, essential for high-power nonlinear optical (NLO) applications. Intriguingly, the title compounds exhibit a measurable contrast in the SHG response under right- and left-handed circularly polarized excitation, thereby providing a unique case of SHG circular dichroism from the chiral centers of SIAP2- or RIAP2- ligand packed in the noncentrosymmetric environment. These exceptional attributes position these HCPs as promising candidates for multifunctional materials, with potential applications ranging from NLO devices to tailored luminescent systems with polarization control.

Glutamic based self-assembly urchin microsphere structure metal organic framework for gas sorption and aluminium ion sensing applications

Bio-molecules based self-assembled nano range metal-organic frameworks (MOFs) potential materials used in recent compact applications. For its structural tunability, large void area, pore volumes and eco-friendly nature. In this work, we report the same composition but different synthesized method glutamic acid cobalt node-based metal-organic compounds GACo1 and GACo2. In this material, GACo2 has the property of a nanocrystalline nature, this fundamental combination forms self-assembly uniform well-developed porous 3D urchin-like microsphere architectures with the dimension of 1.5 µm. The sorption analysis declares N2 adsorbed in the amount of 1544 ccg−1 and surface area is 2695 m2 g−1 without supercritical CO2 treatment. Interestingly, GACo2 MOF acts as a fluorescence probe for Al3+ metal ions in the aqueous phase with high selectivity and sensitivity. The KSV value and detection limit of material were 2.13 × 103 M−1 and 0.0547 × 10−7 M respectively, Also, the limit of detection is significantly lower than the WHO recommendation of Al3+ ion for drinking water ((7.41310−3 M)). Interestingly, the turn-on-sensing ability of GACo2 MOF for Al3+ ions in an aqueous medium was achieved even in the presence of a change in the pH of the solution.

Programmable Monodisperse Glyco-Multivalency Using Self-Assembled Coordination Cages as Scaffolds.

The multivalent presentation of glycans leads to enhanced binding avidity to lectins due to the cluster glycoside effect. Most materials used as scaffolds for multivalent glycan arrays, such as polymers or nanoparticles, have intrinsic dispersity: meaning that in any sample, a range of valencies are presented and it is not possible to determine which fraction(s) are responsible for binding. The intrinsic dispersity of many multivalent glycan scaffolds also limits their reproducibility and predictability. Here we make use of the structurally programmable nature of self-assembled metal coordination cages, with polyhedral metal-ion cores supporting ligand arrays of predictable sizes, to assemble a 16-membered library of perfectly monodisperse glycoclusters displaying valencies from 2 to 24 through a careful choice of ligand/metal combinations. Mono- and trisaccharides are introduced into these clusters, showing that the synthetic route is tolerant of biologically relevant glycans, including sialic acids. The cluster series demonstrates increased binding to a range of lectins as the number of glycans increases. This strategy offers an alternative to current glycomaterials for control of the valency of three-dimensional (3-D) glycan arrays, and may find application across sensing, imaging, and basic biology.

A novel layered double hydroxides oleogel lubricant: Inspired by conventional greases

Grease lubricants serve as a simple, effective and convenient source of lubrication for saving energy. However, the most applicable lithium greases meet contradictory pressures of high performance and low pricing demands because of the substantial development of the global electric vehicles industry and the ubiquity of lithium batteries. In order to alleviate the dependence on lithium resources and develop resource-widespread and economical lubricating grease, herein, a class of thickener and oleogel system based on organic acid intercalated layered double hydroxides (LDHs) inspired by traditional grease has been reported. LDHs materials can be regarded as a preassembled “salt-like” compound, comparable to the self-assembled traditional metal soap salt thickener. LDHs oleogels exhibit viscoelastic properties and tribological performance similar to those of lithium greases. This study presents ideas for future development through layered materials regarding as "salt-like" compounds as a replacement for traditional grease thickeners.

Easy to make highly efficient FG@ACC stable platform for sp3C-CF3 bond generation and NADH regeneration under sun light

The conversion of sun light energy into sustainble greener chemicals are a major obstacle due to the use of expensive and toxic materials. Sun light induced trifluoromethylation emerges as a highly efficient procedure to insert trifluoromethyl groups into the organic compounds. Yet, the expensive and toxic properties of the metal-based photocatalysts creates a major obstacle for the insertion of trifluoromethyl groups. Metal free activated carbon cloth (ACC) emerged as a highly efficient pillar in the area of material science. In this work, we have successfully synthesized self-assembled metal free fast green with activated carbon cloth (FG@ACC) photocatalyst for photocatalytic trifluoromethylation and reduced nicotinamide adenine dinucleotide (NADH) cofactor regeneration (85.89 %, 2 h) under sun light. The sun light induced organic transformation promotes the use of low-cost CF3SO2Na as the CF3 radical source to produce highly selective products with 97% yield.

Resolving Molecular Size and Homologues with a Self-Assembled Metal–Organic Framework Photonic Crystal Detector

Traditional environmental photonic sensing based on the balanced reflection of a photonic structure can hardly be applied to distinguish molecular size and homologues, since the refractive index change introduced by these analytes can be too similar to be unambiguously distinguished. Here, a sensing method based on the pore size selectivity and organics adsorption–desorption capacity of self-assembled ZIF-8 photonics crystal is demonstrated, which can tell apart different molecular sizes, homologues, and organics with similar structures and physical properties. Specificity is improved by the inherent relationships between the pore size of ZIF-8 metal–organic frameworks and the associated molecular diffusion rates in the pores, so that the combination of the observed peak shift and recovery time are unique to each analyte. Using this method, selective detection of molecular size is also demonstrated in the case of linear vs cyclic molecules, since only the former can penetrate inside the ZIF-8 pores to induce a large wavelength shift. The reflection peak shift caused by the linear molecules was found to be about 30–40 nm, an order of magnitude larger compared to those for the cyclic molecules. A relationship between the diffusion rate of linear molecules in ZIF-8 pore and the recovery time of photonic crystal reflective peak is further established, linking the recovery time and the linear molecular diffusion coefficient. Finally, different linear molecules are identified by their associated recovery time to detect homologues or organics with similar refractive index.

Gold vs. Silver Colloidal Nanoparticle Films for Optimized SERS Detection of Propranolol and Electrochemical-SERS Analyses.

The increasing pollution of surface and groundwater bodies by pharmaceuticals is a general environmental problem requiring routine monitoring. Conventional analytical techniques used to quantify traces of pharmaceuticals are relatively expensive and generally demand long analysis times, associated with difficulties in performing field analyses. Propranolol, a widely used β-blocker, is representative of an emerging class of pharmaceutical pollutants with a noticeable presence in the aquatic environment. In this context, we focused on developing an innovative, highly accessible analytical platform based on self-assembled metal colloidal nanoparticle films for the fast and sensitive detection of propranolol based on Surface Enhanced Raman Spectroscopy (SERS). The ideal nature of the metal used as the active SERS substrate was investigated by comparing silver and gold self-assembled colloidal nanoparticle films, and the improved enhancement observed on the gold substrate was discussed and supported by Density Functional Theory calculations, optical spectra analyses, and Finite-Difference Time-Domain simulations. Next, direct detection of propranolol at low concentrations was demonstrated, reaching the ppb regime. Finally, we showed that the self-assembled gold nanoparticle films could be successfully used as working electrodes in electrochemical-SERS analyses, opening the possibility of implementing them in a wide array of analytical applications and fundamental studies. This study reports for the first time a direct comparison between gold and silver nanoparticle films and, thus, contributes to a more rational design of nanoparticle-based SERS substrates for sensing applications.