Synthesis and applications of anisotropic nanoparticles with precisely defined dimensions

Tuning particle aspect ratio and surface roughness to modulate properties in colloidal gels

HYPOTHESIS

Particle shape and surface roughness may have synergistic effects on particle network formation in colloidal gels. Particles with an aspect ratio greater than one have orientation-dependent interactions with neighboring particles compared to spheres, making their interactions highly sensitive to rotational dynamics. By adding surface roughness, we add non-central surface forces and expect to further constrain particle rotation, potentially enhancing the stability and rigidity of networks formed by these particles.

EXPERIMENTS

To this end, smooth and rough particles of different aspect ratios were synthesized and grafted with an octadecyl layer to form a thermoreversible gel in tetradecane. The gels were characterized using rheological and optical methods.

FINDINGS

Surface roughness was found to reduce the percolation threshold and improve sedimentation stability, though its impact diminishes with increasing aspect ratio. Rough particles formed more homogeneous networks, as surface roughness restricts the excluded-volume-driven local alignment in smooth systems. Consequently, elasticity and yielding behavior are more strongly influenced by aspect ratio in smooth rod gels than in rough rod gels.

Atomic Defect-Directed Epitaxial Growth of Multimetallic Nanorods for High-Efficiency Alcohol Electro-Oxidation

Site-selective epitaxial growth of metals onto shaped nanoparticles represents a versatile strategy for tailoring nanostructures to optimize the optical and catalytic properties. In this study, we systematically elucidate the critical factors governing the epitaxial growth of silver and platinum atoms onto gold nanorods (Au NRs), revealing that atomic defects on the Au NR surface dictate the deposition sites of Ag and Pt. By precisely modulating epitaxial growth conditions and density of surface atomic defects, we achieve the synthesis of dumbbell-shaped (DS) and thorny-shell (TS) structured Au-AgPt NRs. Notably, the DS-Au-AgPt0.24 NR catalyst demonstrated exceptional catalytic performance in alcohol fuel cell reactions, driven by their abundant atomic defects and strong strain effects localized at the crown structure. For ethylene glycol electro-oxidation, these DS-Au-AgPt0.24 NRs achieved a mass activity of 23.5 A mgPt-1 and a specific activity of 156.9 mA cm-2, which were 4.1 and 11.2 times higher than that of commercial platinum-carbon (Pt/C) catalysts (5.7 A mgPt-1 and 14.0 mA cm-2), respectively. Our findings not only advance the mechanistic understanding of defect-mediated epitaxial growth in multimetallic systems but also provide a blueprint for designing high-performance catalysts through atomic-scale structural engineering.

A Versatile Route to Shape Polymer Nanoparticles by Deforming Nanoreactors Made from Magnetic Surfactants

Directions are equivalent in an amorphous system, so anisotropy cannot emerge of its own accord, resulting in a gap for preparing polymer nanoparticles deviating from a spherical shape. Unlike inorganic nanocrystals for which faceting controls shape, polymers are not directly available as rod-like particles, for instance. Here, we show a highly versatile, nontoxic, novel approach to break this paradigm and obtain polymer nanorods by emulsion polymerization using a unique surfactant comprising a magnetic head group. Surprisingly, even applying a weak magnetic field to the magnetic surfactant within an emulsion polymerization transforms diamagnetic polymers into rod-like nanoparticles instead of their usual spherical shapes. The polarization in a magnetic field exerts a torque on the molecular structure, and as a result, the emulsion droplets deform. The method can be applied to different polymers such as polystyrene, polymethylmethacrylate, or polythiophene. The magnetic surfactant is recovered quantitatively and can be reused; one obtains metal-free polymer particles, and the process is sustainable. The straightforward approach presented here will unlock several applications of these previously inaccessible polymer nanorods, particularly in the case of conducting polymers.

Ferritin-Inspired Encapsulation and Stabilization of Gold Nanoclusters for High-Performance Photothermal Conversion

Gold nanoclusters (AuNCs) are highly promising for applications in photothermal conversion due to their exceptional surface area and optical properties. However, their high surface energy often leads to aggregation, compromising stability and performance. To address this, we developed a ferritin-inspired covalent organic cage with a near-enclosed cavity to physically stabilize AuNCs. This superphane cage coordinates with Au3⁺ ions, forming highly stable and uniform AuNCs upon reduction. The encapsulated AuNCs exhibit broad absorption (250-2500 nm) and achieve remarkable photothermal conversion efficiency of 92.8% under 808 nm laser irradiation. At low power densities (0.5 W/cm2), temperatures reach 150 °C, and under one-sun illumination (1 kW/m2), the solar-to-vapor generation efficiency reaches 95.1%, with a water evaporation rate of 2.35 kg m-2 h-1. Even after 20 seawater desalination cycles, the system maintains a stable evaporation rate of 2.24 kg m-2 h-1, demonstrating excellent salt tolerance and durability. This ferritin-inspired strategy offers a robust platform for enhancing the stability and performance of AuNCs, advancing sustainable energy and water purification technologies.

Measurement of Anisotropic Exciton Transport Lengths in Organic Crystals Using Photoetching

Measuring anisotropic exciton transport in organic crystals goes beyond just assessing one-dimensional (1D) transport. It offers a deeper understanding of how molecular packing and interactions affect exciton transport in different dimensions. However, achieving nanoscale precision in measuring anisotropic exciton transport lengths and linking them to specific crystalline directions remains a formidable challenge. Here the development of a photoetching method is reported to visualize the exciton transport distances as gaps within two-dimensional (2D) crystals, which in turn allows for the use of a scanning electron microscope (SEM) to precisely measure the sizes. The photoetching method combined with hetero-seeded self-assembly enables the use of conventional fluorescence spectrometry for precise determination of anisotropic exciton transport lengths in 2D structures at the nanoscale. Relying on this novel method, It is unexpectedly found that increasing intermolecular interactions in one crystal direction not only improves exciton transport in that dimension but also enhances exciton transport in the other dimension. These findings provide valuable insights for engineering organic materials that require efficient exciton transport across extended distances.

Precision Stealth Nanofibers via PET-RAFT Polymerisation: Synthesis, Crystallization-driven Self-assembly and Cellular Uptake Studies

Stealth precision polymer nanofibers show great promise as therapeutic delivery systems. However, existing systems are largely limited to poly(ethylene glycol) (PEG) and suffer from challenging functionalization, hampering their translation. This work develops a modular, easily functionalizable platform for biocompatible stealth nanofibers based on a combination of ring-opening polymerisation (ROP), photoinduced electron/energy transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerisation, and crystallization-driven self-assembly (CDSA). Low length-dispersity poly(fluorenetrimethylenecarbonate)-b-poly(N-(2-hydroxypropyl) methacrylamide) (PFTMC-b-PHPMA) nanofibers may be produced in a single-step via CDSA, with a length that is dependent on the PHPMA DPn. Separately, living CDSA leads to nanofibers with length control between 30 nm and ca. 700 nm. Incorporation of fluorescein into the PET-RAFT polymerization results in fluorescent PFTMC-b-PHPMA block copolymers that can undergo CDSA, forming fluorescent nanoparticles for preliminary cell studies. PFTMC-b-PHPMA nanofibers exhibited minimal toxicity to cells as well as limited cellular association, in line with previous studies on neutral polymer nanofibers. In comparison, PFTMC-b-PHPMA nanospheres exhibited no cellular association. These results indicate that the unique shape and core-crystallinity of PFTMC-b-PHPMA nanofibers ideally positions them for use as therapeutic delivery systems. Overall, the results described herein provide the basis for a modular, easily functionalizable platform for precision stealth polymer nanofibers for a variety of prospective biomedical applications.

Exfoliating from high-pressure arsenic-nitrogen compounds: an efficient way to obtain 2D-AsN

AsN compounds show potential for optoelectronic applications and are considered promising candidates for solar cell materials. Here, new arsenic-nitrogen compounds (i.e., AsN, As2N3, AsN3) have been identified under pressure by first-principles calculations. We find that the cubic phase of reported AsN compounds transforms into the newly discovered layered Cmc21 phase at 19 GPa and then transitions to the Pnma phase at 63 GPa. Both layered structures are semiconductors and exhibit dynamic and mechanical stability at 0 GPa, suggesting potential for quenching to ambient pressure. Furthermore, two-dimensional AsN with a structure similar to black phosphorus is proposed to have excellent multifunctionality; however, it has not yet been synthesized. We propose a method to exfoliate monolayer AsN from a layered structure and find that the exfoliation energies of AsN compounds are at least 1 meV Å-2 lower than those of graphene and phosphorene. These findings shed light on the formation conditions and properties of AsN compounds and provide valuable insights for future experimental synthesis.

Plasmonic Geometry-Induced Viscoelastic Biocomplex Formation with Optical Concealment, Liquid Slips, and Soundscapes in Bioassays

Plasmonic nanoparticles (NPs), typically made up of gold or silver, are widely used in point-of-care bio- and chemical sensing due to their role in enhancing detection sensitivity. Key NP properties influencing sensing performance include the material type, NP size, and geometry. While much research has focused on material and size optimization, less attention has been given to understand NP geometry effects and interactions with biomolecules involved in the bioassay. In this context, we investigate the interfacial properties of the biocomplex formed by spherical-shaped gold nanoparticles (AuNPs) and gold nanostars (AuNSts) during a sandwich assay using localized surface plasmon resonance (LSPR) and quartz crystal microbalance with dissipation (QCM-D). The chosen model to study the biocomplex specifically detects interleukin-6 (IL-6). Our results show that AuNSts, with their anisotropic shape and higher surface area, form antibody-antigen complexes more effectively than AuNPs. AuNSts also create a softer, more hydrated layer due to their complex geometry, which leads to larger liquid slips. Lastly, we showed that AuNSts avoid optical concealment at high IL-6 concentrations, unlike AuNPs, making them more reliable for detecting a wider range of concentrations. These findings highlight the importance of optimizing NP geometry for improved bio/chemical sensor performance.

Uniform Single-Domain Liquid Crystalline Hexagonal Rods by Synchronized Polymerization and Self-Assembly Using Disc-Shaped Monomers

The fabrication of nanostructures from polycyclic aromatic hydrocarbons (PAHs) is highly attractive owing to their unique optical, electrical, and magnetic properties. However, the creation of uniform and well-defined PAH nanostructures by self-assembly still remains a significant challenge. Herein, we report that highly uniform hexagonal rods can be obtained from triphenylene (TP)-derived monomers by synchronized polymerization and self-assembly (SPSA). These rods have a single-domain columnar liquid crystalline structure in which columns formed from stacked TPs are along the long axis of the rods. The length/diameter ratios of the rods can be tuned over a wide range. Key factors to achieve SPSA of PAHs were analyzed, and the formation mechanism was clarified. In particular, it is observed that successful SPSA occurs below an upper critical temperature, which could be attributed to insufficient microphase separation between the side chains and the main chains and should be a general principle for SPSA. Furthermore, we demonstrate that the columnar stacking of TP units significantly promotes the intersystem crossing of the singlet excited state to the triplet excited state, resulting in simultaneous fluorescence and phosphorescence emission at room temperature. This work may be extended to a wide range of PAHs to regulate their self-assembly and light emission properties.

Colloidal Synthesis of Thiospinel High-Entropy Sulfide Star-like Nanocrystals with High Cycling Stability for the Oxygen Evolution Reaction

High-entropy semiconducting nanocrystals involving the random incorporation of five or more metals within a single, disordered lattice are receiving significant research interest as catalytic materials. Among these, high-entropy sulfide (HES) nanocrystals demonstrate potential as electrocatalysts but have been slower to gain research interest compared to other high-entropy systems due to the complications introduced by multistep, high-temperature synthesis techniques and the issues of material stability during performance. In this work, we report a simple, reproducible, and scalable HES synthesis to produce star-like nanocrystals. The HES nanocrystals show promise as electrocatalysts with high stability by maintaining a uniform overpotential within 1.5% of the initial value for over 2,200 cycles while rotating, with values as low as 313 mV at 10 mA/cm2 for the oxygen evolution reaction (OER) in alkaline media. Our work provides a low-temperature, colloidal method in the formation of highly complex, phase-pure thiospinel high-entropy sulfide nanocrystals.

Real-time label-free imaging of living crystallization-driven self-assembly

Living crystallization-driven self-assembly (CDSA) of semicrystalline block copolymers is a powerful method for the bottom-up construction of uniform polymer microstructures with complex hierarchies. Improving our ability to engineer such complex particles demands a better understanding of how to precisely control the self-assembly process. Here, we apply interferometric scattering (iSCAT) microscopy to observe the real-time growth of individual poly(ε-caprolactone)-based fibers and platelets. This label-free method enables us to map the role of key reaction parameters on platelet growth rate, size, and morphology. Furthermore, iSCAT provides a contrast mechanism for studying multi-annulus platelets formed via the sequential addition of different unimers, offering insights into the spatial distribution of polymer compositions within a single platelet.

Triggered "On/off" Luminescent Polypeptide Bowl-Shaped Nanoparticles for Selective Lighting of Tumor Cells

Functional polymeric nanoparticles, especially those with anisotropic structures, have shown significant potential and advantages in biomedical applications including detecting, bioimaging, antimicrobial and anticancer. Herein, tetraphenylethylene (TPE) and azobenzene modified polypeptides of poly((L-glutamic acid) tetraphenylethylene-stat-(L-glutamic acid)) (P(GATPE9-stat-GA25)) and poly((L-glutamic acid) azobenzene-stat-(L-glutamic acid)) (P(GAAzo5-stat-GA29) are synthesized, which self-assemble into bowl-shaped nanoparticles (BNPs) with controlled diameter, opening size and fluorescent property individually, or by co-assembly. Due to the quenching effect of azobenzene, the fluorescence of the coassembled BNPs is completely inhibited. Upon incubated under reduction environment, the fluorescence of the BNPs is re-excited owing to the reduction or break of azo bonds. Benefiting from the high-level azo reductase in hypoxic liver cancer cells comparing to normal liver cells, the quenched BNPs exhibit pronounced fluorescence signal in human hepatoma (HepG2) cells under hypoxic condition, demonstrating the high efficiency of the reduction-responsive luminescent BNPs for selective screening of tumor cells. In addition, it is also found that a proper opening size promotes the cellular uptake of the BNPs even with size up to micron. Overall, this study provides a fresh perspective in the controlled preparation of anisotropic polymeric nanoparticles and high efficient cancer cell screening.

Phytochemical Analysis, Isolation, and Characterization of Gentiopicroside from Gentiana kurroo and Cytotoxicity of Biosynthesized Silver Nanoparticles Against HeLa Cells

Gentiana kurroo Royle, a critically endangered Himalayan herb, is valued in treating leucoderma, syphilis, bronchial asthma, hepatitis, etc. The current investigation performed quantitative and qualitative phytochemical analysis of G. kurroo root extracts prepared in chloroform, methanol, and ethyl acetate. The phenolic and flavonoid contents were the highest in methanol and chloroform extract, respectively. Several pharmacologically important compounds were identified through gas chromatography-mass spectrometry. Antioxidant analysis revealed methanolic extract to be the most efficient scavenger of 2,2-diphenyl-1-picrylhydrazyl (IC50 = 114 µg mL-1), hydrogen peroxide (IC50 = 109.9 µg mL-1), and superoxide (IC50 = 74.63 µg mL-1) radicals. Gentiopicroside was isolated from the methanolic root extract through silica-gel column-chromatography, and the characterization of concentrated fractions was achieved employing various analytical techniques. Pertaining to silver nanoparticle (GkAgNPs) synthesis, different physicochemical parameters were optimized and it was observed that root extract treated with silver-nitrate (0.5 mM) at 60 °C and incubated in dark for at least 120 min after initial color change, yielded GkAgNPs optimally. GkAgNPs were anisotropic and polydisperse and exhibited characteristic surface plasmon resonance (424 nm), crystalline face-centered cubic geometry, size (50-300 nm), and zeta-potential (- 16.3 mV). FT-IR spectra indicated the involvement of phenols and flavonoids in AgNPs synthesis. GkAgNPs were evidenced as strongly cytotoxic (IC50 = 1.964 µg mL-1) against HeLa cells and also showed deformed cellular morphology, a significant reduction in viable cell counts and colony-forming efficiency (4.08%). The findings suggest potential applications in drug development for treating serious human diseases. To the best of our knowledge, this study represents the first report on the isolation of gentiopicroside, the bio-fabrication of GkAgNPs using G.kurroo root extract, and their strong bioefficacy against HeLa cells.

Size-Dependent, Topology-Regulated, pH-Change-Tolerable, and Reversible Self-Assembly of Ultrasmall Nanoparticles

The multiscale ordering of colloidal nanoparticles (NPs) endows materials with diverse functions and performances. The controllable and predictable assembly of NPs is essential for the new generation of materials science. This study presents a topology-regulated self-assembly approach in an aqueous environment, utilizing polysorbate 20 (Tween-20) and ultrasmall gold nanoparticles (2, 4, and 8 nm AuNPs). The self-assembly process was governed by polyvalent hydrogen bonding interactions between the amphiphilic Tween-20 and tiopronin-capped NPs, with the amphipathic nature of Tween-20 primarily dictating the transformation from 1D to 3D structures. Notably, the NP size influences the assembly process, with the 2 nm particles demonstrating a well-regulated, pH-stable, and reversible assembly capability. Our findings provide a straightforward approach for controlling the assembly of simple nanoparticles and molecules into higher dimensional nano/microstructures, and close the knowledge gap in how NP size affects interactions within the assembly dynamics.

Creation of Segmented Platelets with Diverse Crystalline Cores Using Double Crystalline Triblock Copolymers

Two-dimensional (2D) platelet structures with uniform dimensions and spatially defined diverse cores are highly sought but are still challenging to access. Living crystallization-driven self-assembly (CDSA)-seeded growth enables the creation of uniform 2D core-shell nanomaterials with diverse core compositions via sequential epitaxial crystallization of block copolymers. Nevertheless, general limitation of the growth process to strict requirements of heteroepitaxial crystallization is a major obstacle to the formation of segmented nanoparticles with extended diverse core chemistries. Herein, we introduce a strategy of using double-crystalline triblock copolymers, such as poly(ε-caprolactone)-block-poly(p-dioxanone)-block-poly(N,N-dimethyl acrylamide) (PCL-b-PPDO-b-PDMA), as bridges to create segmented platelets with compositionally distinct cores. The epitaxial crystallization of the PCL block excludes the PPDO block, forming out-of-plane PPDO crystals that seed subsequent epitaxial crystallization of the added PPDO unimer, producing flat-on quasi-square PPDO crystals. Meanwhile, the less-defined orientation of PPDO crystals has confirmed the presence of flat-on epitaxy between PCL and PPDO. For comparison, PCL-b-PHL (PHL = poly(ζ-heptalactone)) forms in-plane crystals with a strictly defined orientation via edge-on epitaxy due to the cocrystallization of PCL and PHL. Therefore, this approach provides a novel route to construct precisely controlled segmented 2D platelet structures with chemically distinct cores and tunable functionalities, an extension to expand the precise design of complex nanoparticles.

Gas-Releasing Polymer Tubesomes: Boosting Gas Delivery of Nanovehicles via Membrane Stretching

Hydrogen sulfide (H2S), one of the three gas signaling molecules, not only plays a vital role in mediating a series of cellular activities but also manifests exciting applications in clinical therapy. However, one main obstacle in using H2S as a gaseous therapeutic agent is to realize on-demand storage and delivery of gas, and thus, it is of great importance to develop H2S-donating vehicle platforms. Although a variety of polymer-based gas-releasing carriers have been designed, almost all the systems are limited to spherical structures. Here we explore the role of polymer self-assembled morphologies, especially toward those non-spherical nanostructures, on the H2S release capacity. A kind of tubular polymersomes (i.e. tubesomes), formed by the membrane stretching of polythionoester-containing block copolymer vesicles, exhibit enhanced cysteine-responsive H2S-releasing behavior in contrast to their spherical counterparts. Moreover, we found that the amount and rate of H2S release from diverse polymersomes is relied on the extent of membrane elongation, which allows us to regulate the gas releasing kinetics through tailoring the membrane geometries. More importantly, it is demonstrated that the tubesomes as polymer-type H2S donors have better anticancer performance than those spherical polymersomes. This would inspire new possibilities to boost gas therapeutic efficacy through shaping the morphology of gas nanovehicles.

Liquid Crystalline Nanorods by Synchronized Polymerization, Self-Assembly and Oriented Attachment for Utilization in Magnetically Responsive Displays

The creation of anisotropic nanoparticles (NPs) by polymerization and/or self-assembly (SA) has significantly promoted the applications of polymer nanomaterials in many fields. However, polymer nanorods are not easily accessible via conventional polymerization or SA. Here we report a one-step route to synthesize single-domain smectic liquid crystalline (LC) nanorods utilizing oriented attachment (OA) that was usually found in the synthesis of inorganic NPs, synchronized with polymerization and SA. The synchronization was achieved by developing a novel stabilizer derived from a thermo-responsive polyelectrolyte system. Mechanistic studies reveal that controlling the thermo-responsive behavior and the distribution of stabilizers on NPs enabled OA. The LC nanorods can further form hierarchical colloidal LCs, which show much larger light transmittance than that of non-LC nanorods. Moreover, we demonstrate that this LC system can be manipulated by an external magnetic field, thus providing a candidate material for magnetic-responsive display.

Computational Modeling of Pharmaceuticals with an Emphasis on Crossing the Blood-Brain Barrier

The discovery and development of new pharmaceutical drugs is a costly, time-consuming, and highly manual process, with significant challenges in ensuring drug bioavailability at target sites. Computational techniques are highly employed in drug design, particularly to predict the pharmacokinetic properties of molecules. One major kinetic challenge in central nervous system drug development is the permeation through the blood-brain barrier (BBB). Several different computational techniques are used to evaluate both BBB permeability and target delivery. Methods such as quantitative structure-activity relationships, machine learning models, molecular dynamics simulations, end-point free energy calculations, or transporter models have pros and cons for drug development, all contributing to a better understanding of a specific characteristic. Additionally, the design (assisted or not by computers) of prodrug and nanoparticle-based drug delivery systems can enhance BBB permeability by leveraging enzymatic activation and transporter-mediated uptake. Neuroactive peptide computational development is also a relevant field in drug design, since biopharmaceuticals are on the edge of drug discovery. By integrating these computational and formulation-based strategies, researchers can enhance the rational design of BBB-permeable drugs while minimizing off-target effects. This review is valuable for understanding BBB selectivity principles and the latest in silico and nanotechnological approaches for improving CNS drug delivery.

Synthesis of anisotropic gold nanoparticles in binary surfactant mixtures: a review on mechanisms of particle formation

Gold nanoparticles are promising candidates for a wide spectrum of biomedical applications ranging from diagnostics and sensors to therapeutics. Their plasmonic properties are dependent on their size and shape among other factors, which can be controlled by understanding various growth mechanisms. Since the breakthrough of the seed-mediated growth approach reported in 2001, the scientific community has actively engaged in the synthesis of tailored anisotropic gold nanoparticles. Surfactants are known for their shape-controlling abilities and since Nikoobakht and El-Sayed in 2003 used a binary surfactant mixture, this method has been adopted as a common synthesis strategy. A wide range of particle shapes have been produced in binary surfactant mixtures using different synthesis approaches, and different working mechanisms have been proposed. This calls for a thorough and critical evaluation of the synthetic methods with an aim to bridge the link between the use of binary surfactants and the control of morphology of anisotropic gold nanoparticles. This review gives a systematic overview of experimental procedures using binary surfactant mixtures to produce gold nanoparticles with tuned properties. The resulting shapes include gold nanorods, bipyramids, tetrahexahedra, and other anisotropic structures. Different mechanisms proposed based on experimental, simulation and modelling analyses are discussed based on the type of binary surfactant systems. Current challenges that need to be addressed and future prospects that may open up new avenues of applications for anisotropic gold nanoparticles are also discussed.

Dual-Ligand Assisted Anisotropic Assembly for the Construction of NIR-II Light-Propelled Mesoporous Nanomotors

The advent of autonomous nanomotors presents exciting opportunities for nanodrug delivery. However, significant potential remains for enhancing the asymmetry of nanomotors and advancing the development of second near-infrared (NIR-II) light-propelled nanomotors capable of operating within deep tissues. Herein, we developed a dual-ligand assisted anisotropic assembly strategy that enables precise regulation of the interfacial energy between selenium (Se) nanoparticle and periodic mesoporous organosilica (PMO). This strategy facilitates the controllable anisotropic growth of PMO on the Se nanoparticle, leading to the formation of Se&PMO Janus nanohybrids. The exposure ratio of the Se subunit within the Janus nanohybrids can be finely tuned from 0% to 75%. Leveraging the transformability of the Se subunit, a variety of functional MxSe&PMO Janus nanocomposites (MxSe denotes metal selenide) were further derived. As a proof of concept, CuSe&PMO Janus nanohybrids, with NIR-II photothermal properties, were employed as NIR-II light-driven nanomotors. By precisely controlling the exposure ratio of the CuSe subunit within the Janus nanostructure, these CuSe&PMO nanomotors achieved optimal self-propulsion, thus enhancing cellular uptake and promoting deep tumor penetration. Furthermore, the high loading capacity and hydrophobic framework of the PMO subunit enabled the incorporation of hydrophobic disulfiram, thereby significantly boosting the efficacy of synergistic active-motion photothermal therapy.

Precisely Prepared Hierarchical Micelles of Polyfluorene-block-Polythiophene-block-Poly(phenyl isocyanide) via Crystallization-Driven Self-Assembly

The precise preparation of hierarchical micelles is a fundamental challenge in modern materials science and chemistry. Herein, poly(di-n-hexylfluorene)-block-poly(3-tetraethylene glycol thiophene) (poly(1m-b-2n)) diblock copolymers and polyfluorene-block-polythiophene-block-poly(phenyl isocyanide) triblock copolymers were synthesized using a one-pot process via the sequential addition of corresponding monomers using a Ni(II) complex as a single catalyst for living/controlled polymerization. The crystallization-driven self-assembly of amphiphilic conjugated poly(1m-b-2n) led to the formation of nanofibers with controlled lengths and narrow dispersity. The block copolymers exhibited white, yellow, and red emissions in different self-assembly states. By using uniform poly(1m-b-2n) nanofibers as seeds, introducing the polyfluorene-block-polythiophene-block-poly(phenyl isocyanide) triblock polymer as a unimer in the seed growth process, and adjusting the structure of the poly(phenyl isocyanide) block and the polarity of self-assembly solvent, A-B-A triblock micelles, multiarm branched micelles, and raft micelles were prepared.

Surface-Enhanced Raman Spectroscopy for Nitrite Detection

Nitrite is an important chemical intermediate in the nitrogen cycle and is ubiquitously present in environmental and biological systems as a metabolite or additive in the agricultural and food industries. However, nitrite can also be toxic in excessive concentrations. As such, the development of quick, sensitive, and portable assays for its measurement is desirable. In this review, we summarize the working principles and applications of surface-enhanced Raman spectroscopy (SERS) as a rapid, portable, and ultrasensitive method for nitrite detection and showcase its applicability in various water, food, and biological samples. The challenges and opportunities for future developments are also discussed.

Sequence-Defined DNA Polymers: New Tools for DNA Nanotechnology and Nucleic Acid Therapy

Structural DNA nanotechnology offers a unique self-assembly toolbox to construct soft materials of arbitrary complexity, through bottom-up approaches including DNA origami, brick, wireframe, and tile-based assemblies. This toolbox can be expanded by incorporating interactions orthogonal to DNA base-pairing such as metal coordination, small molecule hydrogen bonding, π-stacking, fluorophilic interactions, or the hydrophobic effect. These interactions allow for hierarchical and long-range organization in DNA supramolecular assemblies through a DNA-minimal approach: the use of fewer unique DNA sequences to make complex structures. Here we describe our research group's work to integrate these orthogonal interactions into DNA and its supramolecular assemblies. Using automated solid phase techniques, we synthesized sequence-defined DNA polymers (SDPs) featuring a wide range of functional groups, achieving high yields in the process. These SDPs can assemble into not only isotropic spherical morphologies─such as spherical nucleic acids (SNAs)─but also into anisotropic nanostructures such as 1D nanofibers and 2D nanosheets. Our structural and molecular modeling studies revealed new insights into intermolecular chain packing and intramolecular chain folding, influenced by phosphodiester positioning and SDP sequence. Using these new self-assembly paradigms, we created hierarchical, anisotropic assemblies and developed systems exhibiting polymorphism and chiroptical behavior dependent on the SDP sequence. We could also precisely control the size of our nanofiber assemblies via nucleation-growth supramolecular polymerization and create compartmentalized nanostructures capable of precise surface functionalization.The exquisite control over sequence, composition, and length allowed us to combine our SDPs with nanostructures including DNA wireframe assemblies such as prisms, nanotubes, and cubes to create hybrid, stimuli-responsive assemblies exhibiting emergent structural and functional modes. The spatial control of our assemblies enabled their use as nanoreactors for chemical transformations in several ways: via hybridization chain reaction within SNA coronas, through chemical conjugation within SNA cores, and through a molecular "printing" approach within wireframe assemblies for nanoscale information transfer and the creation of anisotropic "DNA-printed" polymer particles.We have also employed our SDP nanostructures toward biological and therapeutic applications. We demonstrated that our SNAs could serve as both extrinsic and intrinsic therapeutic platforms, with improved cellular internalization and biodistribution profiles, and excellent gene silencing activities. Using SDPs incorporating hydrophobic dendrons, high-affinity and highly specific oligonucleotide binding to human serum albumin was demonstrated. These structures showed an increased stability to nuclease degradation, reduced nonspecific cellular uptake, no toxicity even at high concentrations, and excellent biodistribution beyond the liver, resulting in unprecedented gene silencing activity in various tissues.Control over the sequence has thus presented us with a unique polymeric building block in the form of the SDP, which combines the chemical and structural diversity of polymers with the programmability of DNA. By linking these orthogonal assembly languages, we have discovered new self-assembly rules, created DNA-minimal nanostructures, and demonstrated their utility through a range of applications. Developing this work further will open new avenues in the fields of DNA nanomaterials, nucleic acid therapeutics, as well as block copolymer self-assembly.

Navigating the nano-world future: Harnessing cellulose nanocrystals from green sources for sustainable innovation

Cellulose nanocrystals (CNCs) are a class of materials that have received significant attention in recent years due to their unique properties and potential applications. CNCs are extracted from plant fibers and possess high strength, stiffness, and biocompatibility, making them attractive materials for use in various fields such as biomedical engineering, renewable energy, and nanotechnology. This provides an in-depth discussion of the extraction, characterization, and promising applications of CNCs. Furthermore, it discusses the sources of CNCs and the methods used for their extraction as well as the common techniques used to characterize their properties. This work also highlights various applications of CNCs and their advantages over other materials. The challenges associated with the use of CNCs and the current research efforts to address these challenges were analyzed. In addition, the potential future directions and applications for CNCs were discussed. This review article aims to provide a comprehensive understanding of CNCs and their potential as versatile and sustainable materials.

Liquid-nano-liquid interface-oriented anisotropic encapsulation

Emulsion interface engineering has been widely employed for the synthesis of nanomaterials with various morphologies. However, the instability of the liquid-liquid interface and uncertain interfacial interactions impose significant limitations on controllable fabrications. Here, we developed a liquid-nano-liquid interface-oriented anisotropic encapsulation strategy for fabricating asymmetric nanohybrids. Specifically, functional nanoparticles such as magnetic nanoparticles, lanthanide fluorescent nanoparticles, and Au nanorods were anisotropically encapsulated by mesoporous polydopamine (mPDA). In this emulsion system, the wetting behavior of functional nanoparticles at the water/oil interface could be manipulated by the stabilizer of the emulsion (surfactant), leading to the anisotropic assembly of mPDA shell and resulting in various nanostructures, including core-shell, yolk-shell with small opening, ball-in-bowl, and multipetal structures. Due to their structural asymmetry, inherent magnetic properties, and photothermal properties, the ball-in-bowl structured Fe3O4@SiO2&mPDA nanohybrids, serving as proof of concept for nanomotors, demonstrated effective penetration of bacterial biofilm and promotion of infected wound healing. Overall, our approach offers a different perspective for designing morphologically controllable asymmetric structures based on liquid-nano-liquid interface in microemulsion systems that hold great potential for establishing innovative functional nanomaterials.

Terminal Tryptophan-Directed Anisotropic Self-Assembly for Precise Protein Nanostructure Regulation

A common challenge in nanotechnology is synthesizing nanomaterials with well-defined structures. In particular, it remains a major unresolved challenge to precisely regulate the structure and function of protein nanomaterials, which are structurally diverse, highly ordered, and complex and offer an innovative means that enables a high performance in various nanodevices, which is rarely achievable with other nanomaterials. Here an innovative approach is proposed to fabricating multi-dimensional (0- to 3D) protein nanostructures with functional and structural specialties via molecular-level regulation. This approach is based on a stable, consistent, anisotropic self-assembly of Tobacco mosaic virus (TMV) coat protein-derived engineered building blocks where genetically added tryptophan residues are externally tailored. The unique structural characteristics of each nanostructure above are demonstrated in detail through various analyses (electron microscopy, atomic force microscopy, dynamic light scattering, and small-angle X-ray scattering) and further investigated through molecular dynamics simulations, indicating that this control, anisotropic, and molecular assembly-based approach to regulating protein nanostructures holds great potential for customizing a variety of nanomaterials with unique functions and structures.

Effects of nanoparticle size, shape, and zeta potential on drug delivery

Nanotechnology has brought about a significant revolution in drug delivery, and research in this domain is increasingly focusing on understanding the role of nanoparticle (NP) characteristics in drug delivery efficiency. First and foremost, we center our attention on the size of nanoparticles. Studies have indicated that NP size significantly influences factors such as circulation time, targeting capabilities, and cellular uptake. Secondly, we examine the significance of nanoparticle shape. Various studies suggest that NPs of different shapes affect cellular uptake mechanisms and offer potential advantages in directing drug delivery. For instance, cylindrical or needle-like NPs may facilitate better cellular uptake compared to spherical NPs. Lastly, we address the importance of nanoparticle charge. Zeta potential can impact the targeting and cellular uptake of NPs. Positively charged NPs may be better absorbed by negatively charged cells, whereas negatively charged NPs might perform more effectively in positively charged cells. This review provides essential insights into understanding the role of nanoparticles in drug delivery. The properties of nanoparticles, including size, shape, and charge, should be taken into consideration in the rational design of drug delivery systems, as optimizing these characteristics can contribute to more efficient targeting of drugs to the desired tissues. Thus, research into nanoparticle properties will continue to play a crucial role in the future of drug delivery.

Nanoporous Submicron Gold Particles Enable Nanoparticle-Based Localization Optoacoustic Tomography (nanoLOT)

Localization optoacoustic tomography (LOT) has recently emerged as a transformative super-resolution technique breaking through the acoustic diffraction limit in deep-tissue optoacoustic (OA) imaging via individual localization and tracking of particles in the bloodstream. However, strong light absorption in red blood cells has previously restricted per-particle OA detection to relatively large microparticles, ≈5 µm in diameter. Herein, it is demonstrated that submicron-sized porous gold nanoparticles, ≈600 nm in diameter, can be individually detected for noninvasive super-resolution imaging with LOT. Ultra-high-speed bright-field microscopy revealed that these nanoparticles generate microscopic plasmonic vapor bubbles, significantly enhancing opto-acoustic energy conversion through a nano-to-micro size transformation. Comprehensive in vitro and in vivo tests further demonstrated the biocompatibility and biosafety of the particles. By reducing the detectable particle size by an order of magnitude, nanoLOT enables microangiographic imaging with a significantly reduced risk of embolisms from particle aggregation and opens new avenues to visualize how nanoparticles reach vascular and potentially extravascular targets. The performance of nanoLOT for non-invasive imaging of microvascular networks in the murine brain anticipates new insights into neurovascular coupling mechanisms and longitudinal microcirculatory changes associated with neurodegenerative diseases.

Geometrical impacts of platonic particles on nematic liquid crystal dynamics

Platonic-solid-like particles in liquid crystals offer intriguing opportunities for engineering complex materials with tailored properties. Inspired by platonic solids' geometric simplicity and symmetry, these particles possess well-defined shapes such as cubes, tetrahedra, octahedra, dodecahedra, and icosahedra. When dispersed within nematic liquid-crystalline media, these particles interact with the surrounding medium in intricate ways, influencing the local orientational order of liquid crystal molecules. In this work, we implement continuum simulations to study how the combination of particle shape and surface anchoring gives rise to line defects that follow the edges of the particles and how they are affected by the presence of a Poiseuille flow. Platonic-solid-like particles in liquid crystals have shown promise in diverse applications ranging from photonics and metamaterials to colloidal self-assembly and responsive soft materials.

Crystal-Phase-Selective Etching of Heterophase Au Nanostructures

Selective oxidative etching is one of the most effective ways to prepare hollow nanostructures and nanocrystals with specific exposed facets. The mechanism of selective etching in noble metal nanostructures mainly relies on the different reactivity of metal components and the distinct surface energy of multimetallic nanostructures. Recently, phase engineering of nanomaterials (PEN) offers new opportunities for the preparation of unique heterostructures, including heterophase nanostructures. However, the synthesis of hollow multimetallic nanostructures based on crystal-phase-selective etching has been rarely studied. Here, a crystal-phase-selective etching method is reported to selectively etch the unconventional 4H and 2H phases in the heterophase Au nanostructures. Due to the coating of Pt-based alloy and the crystal-phase-selective etching of 4H-Au in 4H/face-centered cubic (fcc) Au nanowires, the well-defined ladder-like Au@PtAg nanoframes are prepared. In addition, the 2H-Au in the fcc-2H-fcc Au nanorods and 2H/fcc Au nanosheets can also be selectively etched using the same method. As a proof-of-concept application, the ladder-like Au@PtAg nanoframes are used for the electrocatalytic hydrogen evolution reaction (HER) in acidic media, showing excellent performance that is comparable to the commercial Pt/C catalyst.

Optical and Structural Properties of Anisotropic ZnS Nanoparticle Suspensions

We studied the optical and structural properties of highly ordered arrays of surfactant-capped ZnS nanowires (NWs) and nanorods (NRs) in organic suspensions. The photoluminescence (PL) emission measured under different concentrations and postsynthesis washing cycles interestingly showed increasing emission upon decreasing nanoparticle (NP) concentration. Synchrotron small angle X-ray scattering measurements elucidated the liquid-crystal-like structure of the NPs in suspension under different concentrations and temperatures. The NWs are stacked in a simple structure with a hexagonal cross-section, whereas the structure of the NRs is more complex, resembling a smectic-c liquid crystal, and shows unusual thermal expansion versus temperature. The results point out that a certain amount of bound surfactant must be present on the NP surface to maximize the PL intensity.

Fluorescence anisotropic probe for sensing cardiac troponin-I antigen through target-specific antibody-conjugated gold nanoclusters

Fluorescence anisotropy (FA) is a versatile and efficient platform for developing biosensors that rely on the rate of rotations of fluorescence molecular entities in biochemical systems. However, by virtue of its intricate complexity, FA is a neglected and less explored area for developing biosensors. Herein, we experimented with the possibility of developing a fluorescence anisotropic probe to detect cardiac troponin I (cTnI), the gold standard biomarker for acute myocardial infarction, via target-specific monoclonal antibody-conjugated gold nanoclusters. The successful detection of cTnI antigen in clinically relevant concentration with a low detection limit of 0.91 ng mL-1 was achieved. The specific molecular interaction between the cTnI antigen and its monoclonal antibody tagged at the surface of gold nanoclusters has restricted the free rotation of gold nanoclusters and increased the FA value. This incremental increase in FA can be correlated to the concentration of cTnI antigen in the sample, thereby achieving the quantitative linear detection of cTnI.

Hydrothermal synthesis of metal nanoparticles@hydrogels and statistical evaluation of reaction conditions' effects on nanoparticle morphologies

We report a facile green hydrothermal synthesis (HTS) of monoliths of hydrogels decorated with noble metal nanoparticles (NPs). The one-pot approach requires solely water, a polysaccharide able to form a hydrogel, and a salt precursor (Mx+-containing) for the metal NPs. The polysaccharide fulfills three roles: (i) it acts as the reducing agent of Mx+ to M0 under hydrothermal conditions, (ii) it stabilizes NPs surfaces, and (iii) it forms a hydrogel scaffold in which the metal NPs are embedded. The NPs' localization in the hydrogel can be controlled through the gelation mechanism. Specifically, the NPs can either be located on and slightly under the surface of the hydrogel monoliths or in the volume. The former is found when a hydrogel monolith is crosslinked prior to HTS. The latter is observed when the HTS reaction mixture contains a polysaccharide dissolved in H2O, which forms a hydrogel upon cooling. Furthermore, we studied the influence of HTS conditions on NP shapes. To find significant levers towards morphological control, a set of HTS experiments featuring broad ranges of reaction conditions was performed. Subsequently, we employed statistical analyses with multivariate regression fits to evaluate synthesis parameter effects. Thereby, we can link the synthesis parameters of temperature, time, precursor concentration, heating rate, choice of metallic precursor, and type of biopolymer, to morphology descriptors such as diameter, circularity, and polydispersity index. The presented approach is in fine compatible with broad arrays of NPs and can in principle be modified for different chemistries, thereby providing a tool for quantitatively assessing morphological impacts of reaction parameters.

Preparation of viromimetic rod-like nanoparticle vaccines (RLNVax) and study of their humoral immune activation efficacy

Virus-like nanoparticle vaccines can efficiently activate the humoral immune response by cross-linking B cell receptors with their surface multivalent antigen arrays. This structurally dependent mechanism makes it crucial to regulate and optimize structural parameters to enhance the efficacy of nanoparticle vaccines. In this study, we prepared nanoparticle vaccines with different aspect ratios by chemically modifying antigen proteins onto the surfaces of poly(amino acid) nanoparticles of various shapes (spherical, ellipsoidal, and rod-like). This allowed us to investigate the impact of structural anisotropy on the humoral immune activation efficacy of nanoparticle vaccines. Furthermore, the end-group molecules of poly(amino acid) materials possess aggregation-induced emission (AIE) properties, which facilitate monitoring the dynamics of nano-assemblies within the body. Results showed that rod-like nanoparticle vaccines (RLNVax) with a higher aspect ratio (AR = 5) exhibited greater lymph node draining efficiency and could elicit more effective B cell activation compared to conventional isotropic spherical nanoparticle vaccines. In a murine subcutaneous immunization model using ovalbumin (OVA) as a model antigen, RLNVax elicited antigen-specific antibody titers that were about 64 times and 4.6 times higher than those induced by free antigen proteins and spherical nanoparticle vaccines, respectively. Additionally, when combined with an aluminum adjuvant, antibody titers elicited by RLNVax were further enhanced by 4-fold. These findings indicate that the anisotropic rod-like structure is advantageous for improving the humoral immune activation efficacy of nanoparticle vaccines, providing significant insights for the design and optimization of next-generation nanoparticle vaccines.

A Versatile Strategy toward Donor-Acceptor Nanofibers with Tunable Length/Composition and Enhanced Photocatalytic Activity

Living crystallization-driven self-assembly (CDSA) has emerged as an efficient strategy to generate nanofibers of π-conjugated polymers (CPNFs) in a controlled fashion. However, reports of donor-acceptor (D-A) heterojunction CPNFs are extremely rare. The preparation of these materials remains a challenge due to the lack of rational design guidelines for the D-A π-conjugated units. Herein, we report a versatile CDSA strategy based upon carefully designed D-A-co-oligomers in which electron-deficient benzothiadiazole (BT) or dibenzo[b,d]thiophene 5,5-dioxide (FSO) units are attached to the two ends of an oligo(p-phenylene ethynylene) heptamer [BT-OPE7-BT, FSO-OPE7-FSO]. This arrangement with the electron-deficient groups at the two ends of the oligomer enhances the stacking interaction of the A-D-A π-conjugated structure. In contrast, D-A-D structures with a single BT in the middle of a string of OPE units disrupt the packing. We employed oligomers with a terminal alkyne to synthesize diblock copolymers BT-OPE7-BT-b-P2VP and BT-OPE7-BT-b-PNIPAM (P2VP = poly(2-vinylpyridine), PNIPAM = poly(N-isopropylacrylamide)) and FSO-OPE7-FSO-b-P2VP and FSO-OPE7-FSO-b-PNIPAM. CDSA experiments with these copolymers in ethanol were able to generate CPNFs of controlled length by both self-seeding and seeded growth as well as block comicelles with precisely tunable length and composition. Furthermore, the D-A CPNFs with a BT-OPE7-BT-based core demonstrate photocatalytic activity for the photooxidation of sulfide to sulfoxide and benzylamine to N-benzylidenebenzylamine. Given the scope of the oligomer compositions examined and the range of structures formed, we believe that the living CDSA strategy with D-A-based co-oligomers opens future opportunities for the creation of D-A CPNFs with programmable architectures as well as diverse functionalities and applications.

Particle-Based Photoelectrodes for PEC Water Splitting: Concepts and Perspectives

This comprehensive review delves into the intricacies of the photoelectrochemical (PEC) water splitting process, specifically focusing on the design, fabrication, and optimization of particle-based photoelectrodes for efficient green hydrogen production. These photoelectrodes, composed of semiconductor materials, potentially harness light energy and generate charge carriers, driving water oxidation and reduction reactions. The versatility of particle-based photoelectrodes as a platform for investigating and enhancing various semiconductor candidates is explored, particularly the emerging complex oxides with compelling charge transfer properties. However, the challenges presented by many factors influencing the performance and stability of these photoelectrodes, including particle size, shape, composition, morphology, surface modification, and electrode configuration, are highlighted. The review introduces the fundamental principles of semiconductor photoelectrodes for PEC water splitting, presents an exhaustive overview of different synthesis methods for semiconductor powders and their assembly into photoelectrodes, and discusses recent advances and challenges in photoelectrode material development. It concludes by offering promising strategies for improving photoelectrode performance and stability, such as the adoption of novel architectures and heterojunctions.

Impact of nanosilver surface electronic distributions on serum protein interactions and hemocompatibility

The translation of silver-based nanotechnology 'from bench to bedside' requires a deep understanding of the molecular aspects of its biological action, which remains controversial at low concentrations and non-spherical morphologies. Here, we present a hemocompatibility approach based on the effect of the distinctive electronic charge distribution in silver nanoparticles (nanosilver) on blood components. According to spectroscopic, volumetric, microscopic, dynamic light scattering measurements, pro-coagulant activity tests, and cellular inspection, we determine that at extremely low nanosilver concentrations (0.125-2.5μg ml-1), there is a relevant interaction effect on the serum albumin and red blood cells (RBCs). This explanation has its origin in the surface charge distribution of nanosilver particles and their electron-mediated energy transfer mechanism. Prism-shaped nanoparticles, with anisotropic charge distributions, act at the surface level, generating a compaction of the native protein molecule. In contrast, the spherical nanosilver particle, by exhibiting isotropic surface charge, generates a polar environment comparable to the solvent. Both morphologies induce aggregation at NPs/bovine serum albumin ≈ 0.044 molar ratio values without altering the coagulation cascade tests; however, the spherical-shaped nanosilver exerts a negative impact on RBCs. Overall, our results suggest that the electron distributions of nanosilver particles, even at extremely low concentrations, are a critical factor influencing the molecular structure of blood proteins' and RBCs' membranes. Isotropic forms of nanosilver should be considered with caution, as they are not always the least harmful.

Well-Defined Homopolymer Nanoparticles with Uniaxial Molecular Orientation by Synchronized Polymerization and Self-Assembly

Synthesizing anisotropic polymeric nanoparticles (NPs) with well-defined shapes, dimensions, and molecular orientations is a very challenging task. Herein, we report the synthesis of surprisingly highly uniform shape-anisotropic polymer NPs with uniaxial internal molecular orientation. Keys to our method are synchronized polymerization and self-assembly (SPSA), which can even be realized by regular dispersion polymerization. This is demonstrated using a monomer containing a rigid 4-nitroazobenzene (NAB) side group. The short nucleation period, the completion of microphase separation before molecular motion is frozen, and sufficient low particle/solvent interfacial tension are shown to be the origins of the highly uniform dimensions, single liquid crystal domains, and well-defined anisotropic shape of particles. The liquid crystallization ability of the polymers, control of molecular weight distribution, and the polymerization kinetics are identified as three key factors controlling the NP formation. The uniformity of these NPs facilitates their SA formation into colloidal crystals. The particles exhibit optically anisotropic properties depending on orientations and, in particular, show intriguing photoswitchable LC-glass (order-disorder) transition, which can be used for the detection of ultraviolet (UV) light and allows the fabrication of photoreversible colloidal films.

Analyzing the charge contributions of metal-organic framework derived nanosized cobalt nitride/carbon composites in asymmetrical supercapacitors

Metal-organic framework derived nanostructures have recently received research attention owing to their inherent porosity, stability, and structural tailorability. This work involves the conversion of zeolitic imidazolate frameworks (ZIFs) into cobalt nitride nanoparticles embedded within a porous carbon matrix (Co4N/C). The as-prepared composite shows great synergy by providing a high surface area and efficient charge transfer, showcasing outstanding electrochemical performance by providing a specific capacitance of 313 F g-1. Moreover, we meticulously conducted calculations to derive the most precise values for the surface contribution, a crucial aspect often overlooked in existing literature, thereby ensuring the reliability of our calculated measurements. Correct calculations of surface and diffusion charge contributions are necessary for evaluating the overall electrochemical performance of supercapacitors. For practical utility, we successfully assembled an asymmetrical supercapacitor employing the Co4N/carbon composite as the negative electrode that achieved an impressive energy density of 26.6 W h kg-1 at a power density of 0.36 kW kg-1. This study opens up new avenues for investigating the use of other metal nitride nanoparticles embedded in carbon structures for various energy storage applications.

Unlocking Single Particle Anisotropy in Real-Time for Photoelectrochemistry Processes at the Nanoscale

The key to rationally and rapidly designing high-performance materials is the monitoring and comprehension of dynamic processes within individual particles in real-time, particularly to gain insight into the anisotropy of nanoparticles. The intrinsic property of nanoparticles typically varies from one crystal facet to the next under realistic working conditions. Here, we introduce the operando collision electrochemistry to resolve the single silver nanoprisms (Ag NPs) anisotropy in photoelectrochemistry. We directly identify the effect of anisotropy on the plasmonic-assisted electrochemistry at the single NP/electrolyte interface. The statistical collision frequency shows that heterogeneous diffusion coefficients among crystal facets facilitate Ag NPs to undergo direction-dependent mass transfer toward the gold ultramicroelectrode. Subsequently, the current amplitudes of transient events indicate that the anisotropy enables variations in dynamic interfacial electron transfer behaviors during photothermal processes. The results presented here demonstrate that the measurement precision of collision electrochemistry can be extended to the sub-nanoparticle level, highlighting the potential for high-throughput material screening with comprehensive kinetics information at the nanoscale.

Surface Coordination Modulated Morphological Anisotropic Engineering of Iron-Benzoquinone Frameworks for Lithium-Ion Batteries

Morphological anisotropic engineering is powerful to synthesize metal-organic frameworks (MOFs) with versatile physicochemical properties for diverse applications ranging from gas storage/separation to electrocatalysis and batteries, etc. Herein, we developed a carbon substrate guided strategy to manipulate the facet-dependent coordination for morphology engineering of Fe-THBQ (tetrahydroxy-1,4-benzoquinone) frameworks, which is built with cubic Fe octamer bridged by two parallel THBQ ligands along three orthogonal axes, extending to a three-dimensional (3D) framework with pcu-e network topology. The electronegative O-containing functional groups on carbon surfaces compete with THBQ linkers to selectively interact with the unsaturated coordinated Fe cations on the {111} facets and inhibit crystal growth along the <111> direction. The morphology of Fe-THBQ evolves from thermodynamically favored truncated cube to cuboctahedron depending on the content of O-containing functional groups on the carbon substrate. The Fe-THBQ with varied morphologies exhibits facet-dependent performances for electrochemical lithium storage. This work will shed light on the morphology modulation of MOFs for promising applications.

Ultrafine Asymmetric Soft/Stiff Nanohybrids with Tunable Patchiness via a Dynamic Surface-Mediated Assembly

Asymmetric soft-stiff patch nanohybrids with small size, spatially separated organics and inorganics, controllable configuration, and appealing functionality are important in applications, while the synthesis remains a great challenge. Herein, based on polymeric single micelles (the smallest assembly subunit of mesoporous materials), we report a dynamic surface-mediated anisotropic assembly approach to fabricate a new type of small asymmetric organic/inorganic patch nanohybrid for the first time. The size of this asymmetric organic/inorganic nanohybrid is ∼20 nm, which contains dual distinct subunits of a soft organic PS-PVP-PEO single micelle nanosphere (12 nm in size and 632 MPa in Young' modulus) and stiff inorganic SiO2 nanobulge (∼8 nm, 2275 MPa). Moreover, the number of SiO2 nanobulges anchored on each micelle can be quantitatively controlled (from 1 to 6) by dynamically tuning the density (fluffy or dense state) of the surface cap organic groups. This small asymmetric patch nanohybrid also exhibits a dramatically enhanced uptake level of which the total amount of intracellular endocytosis is about three times higher than that of the conventional nanohybrids.

Functional Noncentrosymmetric Nanoparticle-Nanofiber Hybrids via Selective Fragmentation

Noncentrosymmetric nanostructures are an attractive synthetic target as they can exhibit complex interparticle interactions useful for numerous applications. However, generating uniform, colloidally stable, noncentrosymmetric nanoparticles with low aspect ratios is a significant challenge using solution self-assembly approaches. Herein, we outline the synthesis of noncentrosymmetric multiblock co-nanofibers by subsequent living crystallization-driven self-assembly of block co-polymers, spatially confined attachment of nanoparticles, and localized nanofiber fragmentation. Using this strategy, we have fabricated uniform diblock and triblock noncentrosymmetric π-conjugated nanofiber-nanoparticle hybrid structures. Additionally, in contrast to Brownian motion typical of centrosymmetric nanoparticles, we demonstrated that these noncentrosymmetric nanofibers undergo ballistic motion in the presence of H2O2 and thus could be employed as nanomotors in various applications, including drug delivery and environmental remediation.

Biohybrid materials comprising an artificial peroxidase and differently shaped gold nanoparticles

The immobilization of biocatalysts on inorganic supports allows the development of bio-nanohybrid materials with defined functional properties. Gold nanomaterials (AuNMs) are the main players in this field, due to their fascinating shape-dependent properties that account for their versatility. Even though incredible progress has been made in the preparation of AuNMs, few studies have been carried out to analyze the impact of particle morphology on the behavior of immobilized biocatalysts. Herein, the artificial peroxidase Fe(iii)-Mimochrome VI*a (FeMC6*a) was conjugated to two different anisotropic gold nanomaterials, nanorods (AuNRs) and triangular nanoprisms (AuNTs), to investigate how the properties of the nanosupport can affect the functional behavior of FeMC6*a. The conjugation of FeMC6*a to AuNMs was performed by a click-chemistry approach, using FeMC6*a modified with pegylated aza-dibenzocyclooctyne (FeMC6*a-PEG4@DBCO), which was allowed to react with azide-functionalized AuNRs and AuNTs, synthesized from citrate-capped AuNMs. To this end, a literature protocol for depleting CTAB from AuNRs was herein reported for the first time to prepare citrate-AuNTs. The overall results suggest that the nanomaterial shape influences the nanoconjugate functional properties. Besides giving new insights into the effect of the surfaces on the artificial peroxidase properties, these results open up the way for creating novel nanostructures with potential applications in the field of sensing devices.

Synthesis, Structural Analysis, and Peroxidase-Mimicking Activity of AuPt Branched Nanoparticles

Bimetallic nanomaterials have generated significant interest across diverse scientific disciplines, due to their unique and tunable properties arising from the synergistic combination of two distinct metallic elements. This study presents a novel approach for synthesizing branched gold-platinum nanoparticles by utilizing poly(allylamine hydrochloride) (PAH)-stabilized branched gold nanoparticles, with a localized surface plasmon resonance (LSPR) response of around 1000 nm, as a template for platinum deposition. This approach allows precise control over nanoparticle size, the LSPR band, and the branching degree at an ambient temperature, without the need for high temperatures or organic solvents. The resulting AuPt branched nanoparticles not only demonstrate optical activity but also enhanced catalytic properties. To evaluate their catalytic potential, we compared the enzymatic capabilities of gold and gold-platinum nanoparticles by examining their peroxidase-like activity in the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB). Our findings revealed that the incorporation of platinum onto the gold surface substantially enhanced the catalytic efficiency, highlighting the potential of these bimetallic nanoparticles in catalytic applications.

Green Synthesis of CuO Nanoparticles from Macroalgae Ulva lactuca and Gracilaria verrucosa

Macroalgae seaweeds such as Ulva lactuca and Gracilaria verrucosa cause problems on the northern coast of the Italian Adriatic Sea because their overabundance hinders the growth of cultivated clams, Rudatapes philippinarum. This study focused on the green synthesis of CuO nanoparticles from U. lactuca and G. verrucosa. The biosynthesized CuO NPs were successfully characterized using FTIR, XRD, HRTEM/EDX, and zeta potential. Nanoparticles from the two different algae species are essentially identical, with the same physical characteristics and almost the same antimicrobial activities. We have not investigated the cause of this identity, but it seems likely to arise from the reaction of Cu with the same algae metabolites in both species. The study demonstrates that it is possible to obtain useful products from these macroalgae through a green synthesis approach and that they should be considered as not just a cause of environmental and economic damage but also as a potential source of income.

Controlled release of vitamin A palmitate from crosslinked cyclodextrin organic framework for dry eye disease therapy

Controlled release drug delivery systems of eye drops are a promising ophthalmic therapy with advantages of good patient compliance and low irritation. However, the lack of a suitable drug carrier for ophthalmic use limits the development of the aforementioned system. Herein, the crosslinked cyclodextrin organic framework (COF) with a cubic porous structure and a uniform particle size was synthesized and applied to solidify vitamin A palmitate (VAP) by using the solvent-free method. The VAP@COF suspension eye drops were formulated by screening co-solvents, suspending agents, and stabilizing agents to achieve a homogeneous state and improve stability. According to the in vitro release study, the VAP@COF suspension exhibited a controlled release of VAP within 12 h. Both the ex vivo corneal contact angle and in vivo fluorescence tracking indicated that the VAP@COF suspension prolonged the VAP residence time on the ocular surface. This suspension accelerated the recovery of the dry eye disease (DED) model in New Zealand rabbits. Furthermore, the suspension was non-cytotoxic to human corneal epithelial cells and non-irritation to rabbit eyes. In summary, the particulate COF is an eye-acceptable novel carrier that sustains release and prolongs the VAP residence time on the ocular surface for DED treatment.

Frictional behavior of one-dimensional materials: an experimental perspective

The frictional behavior of one-dimensional (1D) materials, including nanotubes, nanowires, and nanofibers, significantly influences the efficient fabrication, functionality, and reliability of innovative devices integrating 1D components. Such devices comprise piezoelectric and triboelectric nanogenerators, biosensing and implantable devices, along with biomimetic adhesives based on 1D arrays. This review compiles and critically assesses recent experimental techniques for exploring the frictional behavior of 1D materials. Specifically, it underscores various measurement methods and technologies employing atomic force microscopy, electron microscopy, and optical microscopy nanomanipulation. The emphasis is on their primary applications and challenges in measuring and characterizing the frictional behavior of 1D materials. Additionally, we discuss key accomplishments over the past two decades in comprehending the frictional behaviors of 1D materials, with a focus on factors such as materials combination, interface roughness, environmental humidity, and non-uniformity. Finally, we offer a brief perspective on ongoing challenges and future directions, encompassing the systematic investigation of the testing environment and conditions, as well as the modification of surface friction through surface alterations.

Easy Synthetic Access to High-Melting Sulfurated Copolymers and their Self-Assembling Diblock Copolymers from Phenylisothiocyanate and Oxetane

Although sulfurated polymers promise unique properties, their controlled synthesis, particularly when it comes to complex and functional architectures, remains challenging. Here, we show that the copolymerization of oxetane and phenyl isothiocyanate selectively yields polythioimidocarbonates as a new class of sulfur containing polymers, with narrow molecular weight distributions (Mn=5-80 kg/mol with Đ≤1.2; Mn,max=124 kg/mol) and high melting points of up to 181 °C. The method tolerates different substituent patterns on both the oxetane and the isothiocyanate. Self-nucleation experiments reveal that π-stacking of phenyl substituents, the presence of unsubstituted polymer backbones, and the kinetically controlled linkage selectivity are key factors in maximising melting points. The increased tolerance to macro-chain transfer agents and the controlled propagation allows the synthesis of double crystalline and amphiphilic diblock copolymers, which can be assembled into micellar- and worm-like structures with amorphous cores in water. In contrast, crystallization driven self-assembly in ethanol gives cylindrical micelles or platelets.

Designing Green Synthesis-Based Silver Nanoparticles for Antimicrobial Theranostics and Cancer Invasion Prevention

Introduction

Researchers are increasingly favouring the use of biological resources in the synthesis of metallic nanoparticles. This synthesis process is quick and affordable. The current study examined the antibacterial and anticancer effects of silver nanoparticles (AgNPs) derived from the Neurada procumbens plant. Biomolecules derived from natural sources can be used to coat AgNPs to make them biocompatible.

Methods

UV-Vis spectroscopy was used to verify the synthesis of AgNPs from Neurada procumbens plant extract, while transmission electron microscopy (TEM), photoluminescence (PL) spectroscopy, dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FTIR) were used to characterize their morphology, crystalline structure, stability, and coating.

Results

UV-visible spectrum of AgNPs shows an absorption peak at 422 nm, indicating the isotropic nature of these nanoparticles. As a result of the emergence of a transmission peak at 804.53 and 615.95 cm-1 in the spectrum of the infrared light emitted by atoms in a sample, FTIR spectroscopy demonstrated that the Ag stretching vibration mode is metal-oxygen (M-O). Electron dispersive X-ray (EDX) spectral analysis shows that elementary silver has a peak at 3 keV. Irradiating the silver surface with electrons, photons, or laser beams triggers the illumination. The emission peak locations have been found between 300 and 550 nm. As a result of DLS analysis, suspended particles showed a bimodal size distribution, with their Z-average particle size being 93.38 nm.

Conclusion

The findings showed that the antibacterial action of AgNPs was substantially (p≤0.05) more evident against Gramme-positive strains (S. aureus and B. cereus) than E. coli. The biosynthesis of AgNPs is an environmentally friendly method for making nanostructures that have antimicrobial and anticancer properties.