How to Build Plasmon-Driven Molecular Jackhammers that Disassemble Cell Membranes and Cytoskeletons in Cancer

Plasmon-driven molecular machines with ultrafast motion at the femtosecond scale are effective for the treatment of cancer and other diseases. It is recently shown that cyanine dyes act as molecular jackhammers (MJH) through vibronic (vibrational and electronic mode coupling) driven activation that causes the molecule to stretch longitudinally and axially through concerted whole molecule vibrations. However, the theoretical and experimental underpinnings of these plasmon-driven motions in molecules are difficult to assess. Here the use of near-infrared (NIR) light-activated plasmons in a broad array of MJH that mechanically disassemble membranes and cytoskeletons in human melanoma A375 cells is described. The characteristics of plasmon-driven molecular mechanical disassembly of supramolecular biological structures are observed and recorded using real-time fluorescence confocal microscopy. Molecular plasmon resonances in MJH are quantified through a new experimental plasmonicity index method. This is done through the measurement of the UV-vis-NIR spectra in various solvents, and quantification of the optical response as a function of the solvent polarity. Structure-activity relationships are used to optimize the synthesis of plasmon-driven MJH, applying them to eradicate human melanoma A375 cells at low lethal concentrations of 75 nm and 80 mW cm-2 of 730 nm NIR-light for 10 min.

Kinetically Controlled Synthesis of Metallic Glass Nanoparticles with Expanded Composition Space

Nanoscale metallic glasses offer opportunities for investigating fundamental properties of amorphous solids and technological applications in biomedicine, microengineering, and catalysis. However, their top-down fabrication is limited by bulk counterpart availability, and bottom-up synthesis remains underexplored due to strict formation conditions. Here, a kinetically controlled flash carbothermic reaction is developed, featuring ultrafast heating (>105 K s-1) and cooling rates (>104 K s-1), for synthesizing metallic glass nanoparticles within milliseconds. Nine compositional permutations of noble metals, base metals, and metalloid (M1─M2─P, M1 = Pt/Pd, M2 = Cu/Ni/Fe/Co/Sn) are synthesized with widely tunable particle sizes and substrates. Through combinatorial development, a substantially expanded composition space for nanoscale metallic glass is discovered compared to bulk counterpart, revealing that the nanosize effect enhances glass forming ability. Leveraging this, several nanoscale metallic glasses are synthesized with composition that have never, to the knowledge, been synthesized in bulk. The metallic glass nanoparticles exhibit high activity in heterogeneous catalysis, outperforming crystalline metal alloy nanoparticles.

Automated Laboratory Kilogram-Scale Graphene Production from Coal

The flash Joule heating (FJH) method converts many carbon feedstocks into graphene in milliseconds to seconds using an electrical pulse. This opens an opportunity for processing low or negative value resources, such as coal and plastic waste, into high value graphene. Here, a lab-scale automation FJH system that allows the synthesis of 1.1 kg of turbostratic flash graphene from coal-based metallurgical coke (MC) in 1.5 h is demonstrated. The process is based on the automated conversion of 5.7 g of MC per batch using an electrical pulse width modulation system to conduct the bottom-up upcycle of MC into flash graphene. This study then compare this method to two other scalable graphene synthesis techniques by both a life cycle assessment and a technoeconomic assessment.

Oxidation of Hydrogen Sulfide to Polysulfide and Thiosulfate by a Carbon Nanozyme: Therapeutic Implications with an Emphasis on Down Syndrome

Hydrogen sulfide (H2 S) is a noxious, potentially poisonous, but necessary gas produced from sulfur metabolism in humans. In Down Syndrome (DS), the production of H2 S is elevated and associated with degraded mitochondrial function. Therefore, removing H2 S from the body as a stable oxide could be an approach to reducing the deleterious effects of H2 S in DS. In this report we describe the catalytic oxidation of hydrogen sulfide (H2 S) to polysulfides (HS2+n - ) and thiosulfate (S2 O3 2- ) by poly(ethylene glycol) hydrophilic carbon clusters (PEG-HCCs) and poly(ethylene glycol) oxidized activated charcoal (PEG-OACs), examples of oxidized carbon nanozymes (OCNs). We show that OCNs oxidize H2 S to polysulfides and S2 O3 2- in a dose-dependent manner. The reaction is dependent on O2 and the presence of quinone groups on the OCNs. In DS donor lymphocytes we found that OCNs increased polysulfide production, proliferation, and afforded protection against additional toxic levels of H2 S compared to untreated DS lymphocytes. Finally, in Dp16 and Ts65DN murine models of DS, we found that OCNs restored osteoclast differentiation. This new action suggests potential facile translation into the clinic for conditions involving excess H2 S exemplified by DS.

Oxidized Activated Charcoal Nanozymes: Synthesis, and Optimization for In Vitro and In Vivo Bioactivity for Traumatic Brain Injury

Carbon-based superoxide dismutase (SOD) mimetic nanozymes have recently been employed as promising antioxidant nanotherapeutics due to their distinct properties. The structural features responsible for the efficacy of these nanomaterials as antioxidants are, however, poorly understood. Here, the process-structure-property-performance properties of coconut-derived oxidized activated charcoal (cOAC) nano-SOD mimetics are studied by analyzing how modifications to the nanomaterial's synthesis impact the size, as well as the elemental and electrochemical properties of the particles. These properties are then correlated to the in vitro antioxidant bioactivity of poly(ethylene glycol)-functionalized cOACs (PEG-cOAC). Chemical oxidative treatment methods that afford smaller, more homogeneous cOAC nanoparticles with higher levels of quinone functionalization show enhanced protection against oxidative damage in bEnd.3 murine endothelioma cells. In an in vivo rat model of mild traumatic brain injury (mTBI) and oxidative vascular injury, PEG-cOACs restore cerebral perfusion rapidly to the same extent as the former nanotube-derived PEG-hydrophilic carbon clusters (PEG-HCCs) with a single intravenous injection. These findings provide a deeper understanding of how carbon nanozyme syntheses can be tailored for improved antioxidant bioactivity, and set the stage for translation of medical applications.

Molecular jackhammers eradicate cancer cells by vibronic-driven action

Through the actuation of vibronic modes in cell-membrane-associated aminocyanines, using near-infrared light, a distinct type of molecular mechanical action can be exploited to rapidly kill cells by necrosis. Vibronic-driven action (VDA) is distinct from both photodynamic therapy and photothermal therapy as its mechanical effect on the cell membrane is not abrogated by inhibitors of reactive oxygen species and it does not induce thermal killing. Subpicosecond concerted whole-molecule vibrations of VDA-induced mechanical disruption can be achieved using very low concentrations (500 nM) of aminocyanines or low doses of light (12 J cm-2, 80 mW cm-2 for 2.5 min), resulting in complete eradication of human melanoma cells in vitro. Also, 50% tumour-free efficacy in mouse models for melanoma was achieved. The molecules that destroy cell membranes through VDA have been termed molecular jackhammers because they undergo concerted whole-molecule vibrations. Given that a cell is unlikely to develop resistance to such molecular mechanical forces, molecular jackhammers present an alternative modality for inducing cancer cell death.

Distinguishing Molecular Mechanical Action from Photothermal and Photodynamic Behavior

Molecular motors (MM) are molecular machines, or nanomachines, that rotate unidirectionally upon photostimulation and perform mechanical work on their environment. In the last several years, it has been shown that the photomechanical action of MM can be used to permeabilize lipid bilayers, thereby killing cancer cells and pathogenic microorganisms and controlling cell signaling. The work contributes to a growing acknowledgement that the molecular actuation characteristic of these systems is useful for various applications in biology. However, the mechanical effects of molecular motion on biological materials are difficult to disentangle from photodynamic and photothermal action, which are also present when a light-absorbing fluorophore is irradiated with light. Here, an overview of the key methods used by various research groups to distinguish the effects of photomechanical, photodynamic, and photothermal action is provided. It is anticipated that this discussion will be helpful to the community seeking to use MM to develop new and distinctive medical technologies that result from mechanical disruption of biological materials.

Cathode Interface Construction by Rapid Sintering in Solid-State Batteries

Solid-state batteries (SSBs) are poised to replace traditional organic liquid-electrolyte lithium-ion batteries due to their higher safety and energy density. Oxide-based solid electrolytes (SEs) are particularly attractive for their stability in air and inability to ignite during thermal runaway. However, achieving high-performance in oxide-based SSBs requires the development of an intimate and robust SE-cathode interface to overcome typically large interfacial resistances. The transition interphase should be both physically and chemically active. This study presents a thin, conductive interphase constructed between lithium aluminum titanium phosphate and lithium cobalt oxide using a rapid sintering method that modifies the interphase within 10 s. The rapid heating and cooling rates restrict side reactions and interdiffusion on the interface. SSBs with thick composite cathodes demonstrate a high initial capacity of ≈120 mAh g-1 over 200 cycles at room temperature. Furthermore, the rapid sintering method can be extended to other cathode systems under similar conditions. These findings highlight the importance of constructing an appropriate SE-cathode interface and provide insight into designing practical SSBs.

Nonlethal Molecular Nanomachines Potentiate Antibiotic Activity Against Gram-Negative Bacteria by Increasing Cell Permeability and Attenuating Efflux

Antibiotic resistance is a pressing public health threat. Despite rising resistance, antibiotic development, especially for Gram-negative bacteria, has stagnated. As the traditional antibiotic research and development pipeline struggles to address this growing concern, alternative solutions become imperative. Synthetic molecular nanomachines (MNMs) are molecular structures that rotate unidirectionally in a controlled manner in response to a stimulus, such as light, resulting in a mechanical action that can propel molecules to drill into cell membranes, causing rapid cell death. Due to their broad destructive capabilities, clinical translation of MNMs remains challenging. Hence, here, we explore the ability of nonlethal visible-light-activated MNMs to potentiate conventional antibiotics against Gram-negative bacteria. Nonlethal MNMs enhanced the antibacterial activity of various classes of conventional antibiotics against Gram-negative bacteria, including those typically effective only against Gram-positive strains, reducing the antibiotic concentration required for bactericidal action. Our study also revealed that MNMs bind to the negatively charged phospholipids of the bacterial inner membrane, leading to permeabilization of the cell envelope and impairment of efflux pump activity following light activation of MNMs. The combined effects of MNMs on membrane permeability and efflux pumps resulted in increased antibiotic accumulation inside the cell, reversing antibiotic resistance and attenuating its development. These results identify nonlethal MNMs as pleiotropic antibiotic enhancers or adjuvants. The combination of MNMs with traditional antibiotics is a promising strategy against multidrug-resistant Gram-negative infections. This approach can reduce the amount of antibiotics needed and slow down antibiotic resistance development, thereby preserving the effectiveness of our current antibiotics.

Low-temperature grapho-epitaxial La-substituted BiFeO3 on metallic perovskite

Bismuth ferrite has garnered considerable attention as a promising candidate for magnetoelectric spin-orbit coupled logic-in-memory. As model systems, epitaxial BiFeO3 thin films have typically been deposited at relatively high temperatures (650-800 °C), higher than allowed for direct integration with silicon-CMOS platforms. Here, we circumvent this problem by growing lanthanum-substituted BiFeO3 at 450 °C (which is reasonably compatible with silicon-CMOS integration) on epitaxial BaPb0.75Bi0.25O3 electrodes. Notwithstanding the large lattice mismatch between the La-BiFeO3, BaPb0.75Bi0.25O3, and SrTiO3 (001) substrates, all the layers in the heterostructures are well ordered with a [001] texture. Polarization mapping using atomic resolution STEM imaging and vector mapping established the short-range polarization ordering in the low temperature grown La-BiFeO3. Current-voltage, pulsed-switching, fatigue, and retention measurements follow the characteristic behavior of high-temperature grown La-BiFeO3, where SrRuO3 typically serves as the metallic electrode. These results provide a possible route for realizing epitaxial multiferroics on complex-oxide buffer layers at low temperatures and opens the door for potential silicon-CMOS integration.

Replacement of Concrete Aggregates with Coal-Derived Flash Graphene

Each year, the growth of cities across developing economies in Asia, Africa, and Latin America drives demand for concrete to house and serve their burgeoning populations. Since 1950, the number of people living in urban areas has quadrupled to 4.2 billion, with another predicted 2.5 billion expected to join them in the next three decades. The largest component of concrete by volume is aggregates, such as sand and rocks, with sand as the most mined material in the world. However, the extraction rate of sand currently exceeds its natural replenishment rate, meaning that a global concrete-suitable sand shortage is extremely likely. As such, replacements for fine aggregates, such as sand, are in demand. Here, flash Joule heating (FJH) is used to convert coal-derived metallurgical coke (MC) into flash graphene aggregate (FGA), a blend of MC-derived flash graphene (MCFG), which mimics a natural aggregate (NA) in size. While graphene and graphene oxide have previously been used as reinforcing additives to concrete, in this contribution, FGA is used as a total aggregate replacement for NA, resulting in 25% lighter concrete with increases in toughness, peak strain, and specific compressive strength of 32, 33, and 21%, respectively, with a small reduction in specific Young's modulus of 11%. FJH can potentially enable the replacement of fine NA with FGA, resulting in lighter, stronger concrete.

Synthesis of Clean Hydrogen Gas from Waste Plastic at Zero Net Cost

Hydrogen gas (H2 ) is the primary storable fuel for pollution-free energy production, with over 90 million tonnes used globally per year. More than 95% of H2 is synthesized through metal-catalyzed steam methane reforming that produces 11 tonnes of carbon dioxide (CO2 ) per tonne H2 . "Green H2 " from water electrolysis using renewable energy evolves no CO2 , but costs 2-3× more, making it presently economically unviable. Here catalyst-free conversion of waste plastic into clean H2 along with high purity graphene is reported. The scalable procedure evolves no CO2 when deconstructing polyolefins and produces H2 in purities up to 94% at high mass yields. The sale of graphene byproduct at just 5% of its current value yields H2 production at a negative cost. Life-cycle assessment demonstrates a 39-84% reduction in emissions compared to other H2 production methods, suggesting the flash H2 process to be an economically viable, clean H2 production route.

High-temperature electrothermal remediation of multi-pollutants in soil

Soil contamination is an environmental issue due to increasing anthropogenic activities. Existing processes for soil remediation suffer from long treatment time and lack generality because of different sources, occurrences, and properties of pollutants. Here, we report a high-temperature electrothermal process for rapid, water-free remediation of multiple pollutants in soil. The temperature of contaminated soil with carbon additives ramps up to 1000 to 3000 °C as needed within seconds via pulsed direct current input, enabling the vaporization of heavy metals like Cd, Hg, Pb, Co, Ni, and Cu, and graphitization of persistent organic pollutants like polycyclic aromatic hydrocarbons. The rapid treatment retains soil mineral constituents while increases infiltration rate and exchangeable nutrient supply, leading to soil fertilization and improved germination rates. We propose strategies for upscaling and field applications. Techno-economic analysis indicates the process holds the potential for being more energy-efficient and cost-effective compared to soil washing or thermal desorption.

Capacitively Coupled Plasma from Laser-Induced Graphene Points to Ozone as the Major Mediator of Antibacterial Activity

Low-temperature plasma is an emerging approach for the treatment of bacterial infections. Nonchemical treatments such as cold plasma offer potential solutions to antibiotic resistance. We investigated the use of laser-induced graphene as an inexpensive, lightweight, and portable electrode for generating cold plasma. At the same time, the mechanism or molecular mediators of cold plasma-induced antibacterial activity remain poorly understood. This study validates graphene as an efficient structure for producing therapeutic cold plasma, and this study also indicates that ozone is the primary mediator of antibacterial activity in graphene-mediated cold plasmas for bacterial growth under the conditions studied.

Battery metal recycling by flash Joule heating

The staggering accumulation of end-of-life lithium-ion batteries (LIBs) and the growing scarcity of battery metal sources have triggered an urgent call for an effective recycling strategy. However, it is challenging to reclaim these metals with both high efficiency and low environmental footprint. We use here a pulsed dc flash Joule heating (FJH) strategy that heats the black mass, the combined anode and cathode, to >2100 kelvin within seconds, leading to ~1000-fold increase in subsequent leaching kinetics. There are high recovery yields of all the battery metals, regardless of their chemistries, using even diluted acids like 0.01 M HCl, thereby lessening the secondary waste stream. The ultrafast high temperature achieves thermal decomposition of the passivated solid electrolyte interphase and valence state reduction of the hard-to-dissolve metal compounds while mitigating diffusional loss of volatile metals. Life cycle analysis versus present recycling methods shows that FJH significantly reduces the environmental footprint of spent LIB processing while turning it into an economically attractive process.

Graphene as a rational interface for enhanced adsorption of microcystin-LR from water

Cyanotoxins such as microcystin-LR (MC-LR) represent a global environmental threat to ecosystems and drinking water supplies. The study investigated the direct use of graphene as a rational interface for removal of MC-LR via interactions with the aromatic ring of the ADDA1 chain of MC-LR and the sp2 hybridized carbon network of graphene. Intra-particle diffusion model fit indicated the high mesoporosity of graphene provided significant enhancements to both adsorption capacities and kinetics when benchmarked against microporous granular activated carbon (GAC). Graphene showed superior MC-LR adsorption capacity of 75.4 mg/g (Freundlich model) compared to 0.982 mg/g (Langmuir model) for GAC. Sorption kinetic studies showed graphene adsorbs 99% of MC-LR in 30 min, compared to zero removal for GAC after 24 hr using the same MC-LR concentration. Density functional theory (DFT), calculations showed that postulated π-based interactions align well with the NMR-based experimental work used to probe primary interactions between graphene and MC-LR adduct. This study proved that π-interactions between the aromatic ring on MC-LR and graphene sp2 orbitals are a dominant interaction. With rapid kinetics and adsorption capacities much higher than GAC, it is anticipated that graphene will offer a novel molecular approach for removal of toxins and emerging contaminants with aromatic systems.

Molecular machines stimulate intercellular calcium waves and cause muscle contraction

Intercellular calcium waves (ICW) are complex signalling phenomena that control many essential biological activities, including smooth muscle contraction, vesicle secretion, gene expression and changes in neuronal excitability. Accordingly, the remote stimulation of ICW could result in versatile biomodulation and therapeutic strategies. Here we demonstrate that light-activated molecular machines (MM)-molecules that perform mechanical work on the molecular scale-can remotely stimulate ICW. MM consist of a polycyclic rotor and stator that rotate around a central alkene when activated with visible light. Live-cell calcium-tracking and pharmacological experiments reveal that MM-induced ICW are driven by the activation of inositol-triphosphate-mediated signalling pathways by unidirectional, fast-rotating MM. Our data suggest that MM-induced ICW can control muscle contraction in vitro in cardiomyocytes and animal behaviour in vivo in Hydra vulgaris. This work demonstrates a strategy for directly controlling cell signalling and downstream biological function using molecular-scale devices.

Bifunctional Gas Diffusion Electrode Enables In Situ Separation and Conversion of CO2 to Ethylene from Dilute Stream

The requirement of concentrated carbon dioxide (CO₂ ) feedstock significantly limits the economic feasibility of electrochemical CO₂ reduction (eCO₂ R) which often involves multiple intermediate processes, including CO₂ capture, energy-intensive regeneration, compression, and transportation. Herein, a bifunctional gas diffusion electrode (BGDE) for separation and eCO₂ R from a low-concentration CO₂ stream is reported. The BGDE is demonstrated for the selective production of ethylene (C₂ H₄ ) by combining high-density-polyethylene-derived porous carbon (HPC) as a physisorbent with polycrystalline copper as a conversion catalyst. The BGDE shows substantial tolerance to 10 vol% CO₂ exhibiting a Faradaic efficiency of ≈45% toward C₂ H₄ at a current density of 80 mA cm^-2 , outperforming previous reports that utilized such partial pressure (P_CO2 = 0.1 atm and above) and unaltered polycrystalline copper. Molecular dynamics simulation and mixed gas permeability assessment reveal that such selective performance is ensured by high CO₂ uptake of the microporous HPC as well as continuous desorption owing to the molecular diffusion and concentration gradient created by the binary flow of CO₂ and nitrogen (CO₂ |N₂ ) within the sorbent boundary. Based on detailed techno-economic analysis, it is concluded that this in situ process can be economically compelling by precluding the C₂ H₄ production cost associated with the energy-intensive intermediate steps of the conventional decoupled process.

Coal-Based Carbon Nanomaterials: En Route to Clean Coal Conversion toward Net Zero CO2

As the world is committed to reach carbon peak by 2030 and net zero by 2050, the use of coal as an energy source is facing unprecedented challenges. According to the International Energy Agency (IEA), global annual coal demand is estimated to drop from more than 5640 million tonnes of coal equivalent (Mtce) in 2021 to 540 Mtce in 2050 under the net zero emission scenario, mostly being replaced by renewable energy such as solar and wind. Therefore, the coal industry is vigorously seeking alternative applications to keep it thriving, and nanotechnology can be one of the contributors. Herein, the challenges to coal-based carbon nanomaterials syntheses are outlined, along with a path toward commercialization. Coal-based carbon nanomaterials can be promising contributors to the concept of clean coal conversion, initiating its migration from an energy source to a high-value-added carbon source.

Upcycling of Waste Plastic into Hybrid Carbon Nanomaterials

Graphitic 1D and hybrid nanomaterials represent a powerful solution in composite and electronic applications due to exceptional properties, but large-scale synthesis of hybrid materials has yet to be realized. Here, a rapid, scalable method to produce graphitic 1D materials from polymers using flash Joule heating (FJH) is reported. This avoids lengthy chemical vapor deposition and uses no solvent or water. The flash 1D materials (F1DM), synthesized using a variety of earth-abundant catalysts, have controllable diameters and morphologies by parameter tuning. Furthermore, the process can be modified to form hybrid materials, with F1DM bonded to turbostratic graphene. In nanocomposites, F1DM outperform commercially available carbon nanotubes. Compared to current 1D material synthetic strategies using life cycle assessment, FJH synthesis represents an 86-92% decrease in cumulative energy demand and 92-94% decrease in global-warming potential. This work suggests that FJH affords a cost-effective and sustainable route to upcycle waste plastic into valuable 1D and hybrid nanomaterials.

Visible-Light-Activated Molecular Machines Kill Fungi by Necrosis Following Mitochondrial Dysfunction and Calcium Overload

Invasive fungal infections are a growing public health threat. As fungi become increasingly resistant to existing drugs, new antifungals are urgently needed. Here, it is reported that 405-nm-visible-light-activated synthetic molecular machines (MMs) eliminate planktonic and biofilm fungal populations more effectively than conventional antifungals without resistance development. Mechanism-of-action studies show that MMs bind to fungal mitochondrial phospholipids. Upon visible light activation, rapid unidirectional drilling of MMs at ≈3 million cycles per second (MHz) results in mitochondrial dysfunction, calcium overload, and ultimately necrosis. Besides their direct antifungal effect, MMs synergize with conventional antifungals by impairing the activity of energy-dependent efflux pumps. Finally, MMs potentiate standard antifungals both in vivo and in an ex vivo porcine model of onychomycosis, reducing the fungal burden associated with infection.

Directing and Understanding the Translation of a Single Molecule Dipole

Understanding the directed motion of a single molecule on surfaces is not only important in the well-established field of heterogeneous catalysis but also for the design of artificial nanoarchitectures and molecular machines. Here, we report how the tip of a scanning tunneling microscope (STM) can be used to control the translation direction of a single polar molecule. Through the interaction of the molecular dipole with the electric field of the STM junction, it was found that both translations and rotations of the molecule occur. By considering the location of the tip with respect to the axis of the dipole moment, we can deduce the order in which rotation and translation take place. While the molecule-tip interaction dominates, computational results suggest that the translation is influenced by the surface direction along which the motion takes place.

Autonomous Single-Molecule Manipulation Based on Reinforcement Learning

Building nanostructures one-by-one requires precise control of single molecules over many manipulation steps. The ideal scenario for machine learning algorithms is complex, repetitive, and time-consuming. Here, we show a reinforcement learning algorithm that learns how to control a single dipolar molecule in the electric field of a scanning tunneling microscope. Using about 2250 iterations to train, the algorithm learned to manipulate the molecule toward specific positions on the surface. Simultaneously, it generates physical insights into the movement as well as orientation of the molecule, based on the position where the electric field is applied relative to the molecule. This reveals that molecular movement is strongly inhibited in some directions, and the torque is not symmetric around the dipole moment.

Chirality-Specific Unidirectional Rotation of Molecular Motors on Cu(111)

Molecular motors have chemical properties that enable unidirectional motion, thus breaking microscopic reversibility. They are well studied in solution, but much less is known regarding their behavior on solid surfaces. Here, single motor molecules adsorbed on a Cu(111) surface are excited by voltages pulses from an STM tip, which leads to their rotation around a fixed pivot point. Comparison with calculations shows that this axis results from a chemical bond of a sulfur atom in the chemical structure and a metal atom of the surface. While statistics show approximately equal rotations in both directions, clockwise and anticlockwise, a detailed study reveals that these motions are enantiomer-specific. Hence, the rotation direction of each individual molecule depends on its chirality, which can be determined from STM images. At first glance, these dynamics could be assigned to the activation of the motor molecule, but our results show that this is unlikely as the molecule remains in the same conformation after rotation. Additionally, a control molecule, although it lacks unidirectional rotation in solution, also shows unidirectional rotation for each enantiomer. Hence, it seems that the unidirectional rotation is not specifically related to the motor property of the molecule. The calculated energy barriers for motion show that the propeller-like motor activity requires higher energy than the simple rotation of the molecule as a rigid object, which is therefore preferred.

Tunable Hybridized Morphologies Obtained through Flash Joule Heating of Carbon Nanotubes

Hybrid carbon nanomaterials, such as those that incorporate carbon nanotubes into graphene sheets, have been found to display interesting mechanical and electrical properties because of their covalent bonding and π-π stacking domains. However, synthesis of these hybrid materials is limited by the high energetic cost of techniques like chemical vapor deposition. Here, we demonstrate the solvent- and gas-free synthesis of a 2D carbon nanotube/graphene network through flash Joule heating of pristine carbon nanotubes. The relative proportion of each morphology in the hybrid material can be tuned by varying the pulse time, as confirmed by Raman spectroscopy and microscopy. Triboindentation of epoxy composites made with the hybrid material shows increases of 162% and 64% to the hardness and Young's modulus, respectively, compared with the neat epoxy. These results demonstrate that flash Joule heating can be used to inexpensively convert carbon nanotubes into a hybrid network of nanotubes and graphene for use as an effective reinforcing additive in epoxy composites.

Flash Recycling of Graphite Anodes

The ever-increasing production of commercial lithium-ion batteries (LIBs) will result in a staggering accumulation of waste when they reach their end of life. A closed-loop solution, with effective recycling of spent LIBs, will lessen both the environmental impacts and economic cost of their use. Presently, <5% of spent LIBs are recycled and the regeneration of graphite anodes has, unfortunately, been mostly overlooked despite the considerable cost of battery-grade graphite. Here, an ultrafast flash recycling method to regenerate the graphite anode is developed and valuable battery metal resources are recovered. Selective Joule heating is applied for only seconds to efficiently decompose the resistive impurities. The generated inorganic salts, including lithium, cobalt, nickel, and manganese, can be easily recollected from the flashed anode waste using diluted acid, specifically 0.1 m HCl. The flash-recycled anode preserves the graphite structure and is coated with a solid-electrolyte-interphase-derived carbon shell, contributing to high initial specific capacity, superior rate performance, and cycling stability, when compared to anode materials recycled using a high-temperature-calcination method. Life-cycle-analysis relative to current graphite production and recycling methods indicate that flash recycling can significantly reduce the total energy consumption and greenhouse gas emission while turning anode recycling into an economically advantageous process.

Probing the Rotary Cycle of Amine-Substituted Molecular Motors

An understanding of the rotary cycle of molecular motors (MMs), a key component of an approach to opening cells using mechanical motion, is important in furthering the research. Nuclear magnetic resonance (NMR) spectroscopy was used for in situ analysis of illuminated light-active MMs. We found that the presence of a N,N-dimethylethylenediamine in a position conjugated to the central olefin results in changes to the rotation of a second-generation Feringa-type MM. Importantly, the addition decreases the photostability of the compound. The parent compound 1 can withstand >2 h of illumination with no signs of decomposition, while the amino 7 decomposes after 10 min. We found that the degradation can be mitigated by implementing the simple techniques of modulating the light dose, dilution, and stirring the sample while illuminating. Additionally, the presence of moisture affects the rate of the motor's rotation. The addition of the amino group to 1, without moisture present, makes the rotation of motor 7 three times slower than the unfunctionalized parent compound. We also report the use of a method that can be used to determine the molar extinction coefficient of a light-generated metastable species. This method can be used when in situ NMR illumination is not available.

A Scalable CMOS Molecular Electronics Chip for Single-Molecule Biosensing

This work reports the first CMOS molecular electronics chip. It is configured as a biosensor, where the primary sensing element is a single molecule "molecular wire" consisting of a ∼100 GΩ, 25 nm long alpha-helical peptide integrated into a current monitoring circuit. The engineered peptide contains a central conjugation site for attachment of various probe molecules, such as DNA, proteins, enzymes, or antibodies, which program the biosensor to detect interactions with a specific target molecule. The current through the molecular wire under a dc applied voltage is monitored with millisecond temporal resolution. The detected signals are millisecond-scale, picoampere current pulses generated by each transient probe-target molecular interaction. Implemented in a 0.18 μm CMOS technology, 16k sensors are arrayed with a 20 μm pitch and read out at a 1 kHz frame rate. The resulting biosensor chip provides direct, real-time observation of the single-molecule interaction kinetics, unlike classical biosensors that measure ensemble averages of such events. This molecular electronics chip provides a platform for putting molecular biosensing "on-chip" to bring the power of semiconductor chips to diverse applications in biological research, diagnostics, sequencing, proteomics, drug discovery, and environmental monitoring.

Chronic exposure to carbon black ultrafine particles reprograms macrophage metabolism and accelerates lung cancer

Chronic exposure to airborne carbon black ultrafine (nCB) particles generated from incomplete combustion of organic matter drives IL-17A-dependent emphysema. However, whether and how they alter the immune responses to lung cancer remains unknown. Here, we show that exposure to nCB particles increased PD-L1⁺ PD-L2⁺ CD206⁺ antigen-presenting cells (APCs), exhausted T cells, and T_reg cells. Lung macrophages that harbored nCB particles showed selective mitochondrial structure damage and decreased oxidative respiration. Lung macrophages sustained the HIF1α axis that increased glycolysis and lactate production, culminating in an immunosuppressive microenvironment in multiple mouse models of non-small cell lung cancers. Adoptive transfer of lung APCs from nCB-exposed wild type to susceptible mice increased tumor incidence and caused early metastasis. Our findings show that nCB exposure metabolically rewires lung macrophages to promote immunosuppression and accelerates the development of lung cancer.

Sustainable valorization of asphaltenes via flash joule heating

The refining process of petroleum crude oil generates asphaltenes, which poses complicated problems during the production of cleaner fuels. Following refining, asphaltenes are typically combusted for reuse as fuel or discarded into tailing ponds and landfills, leading to economic and environmental disruption. Here, we show that low-value asphaltenes can be converted into a high-value carbon allotrope, asphaltene-derived flash graphene (AFG), via the flash joule heating (FJH) process. After successful conversion, we develop nanocomposites by dispersing AFG into a polymer effectively, which have superior mechanical, thermal, and corrosion-resistant properties compared to the bare polymer. In addition, the life cycle and technoeconomic analysis show that the FJH process leads to reduced environmental impact compared to the traditional processing of asphaltene and lower production cost compared to other FJH precursors. Thus, our work suggests an alternative pathway to the existing asphaltene processing that directs toward a higher value stream while sequestering downstream emissions from the processing.

Sustainable 3D Printing of Recyclable Biocomposite Empowered by Flash Graphene

Sustainability of 3D printing can be reflected in three main aspects: deployment of renewable inks, recycling of printed products, and applications for energy- and materials- savings. In this work, we demonstrated sustainable vat-photopolymerization (VPP)-based 3D printing in a whole life-cycle process by developing a renewable ink made of soybean oil and natural polyphenols and recycling the ink for reprinting or converting printed biocomposite to flash graphene (FG) as reinforcing nanofillers in the biocomposite. We also realized its applications in fabricating lightweight, materials-saving 3D structures, acoustic metamaterials, and disposable microreactors for time-saving and efficiency-improving synthesis of metal-organic framework nanostructures. In addition to enhancing the tensile strength and Young's modulus of the biopolymers by 42% and 232% with only 0.6 wt % FG nanofillers, respectively, FG improved the printability of the ink in forming 3D tubular structures, which are usually very hard to be achieved in transparent resin. Success of this work will inspire further development for sustainability in 3D printing.

Hemithioindigo-Based Visible Light-Activated Molecular Machines Kill Bacteria by Oxidative Damage

Antibiotic resistance is a growing health threat. There is an urgent and critical need to develop new antimicrobial modalities and therapies. Here, a set of hemithioindigo (HTI)-based molecular machines capable of specifically killing Gram-positive bacteria within minutes of activation with visible light (455 nm at 65 mW cm^-2 ) that are safe for mammalian cells is described. Importantly, repeated exposure of bacteria to HTI does not result in detectable development of resistance. Visible light-activated HTI kill both exponentially growing bacterial cells and antibiotic-tolerant persister cells of various Gram-positive strains, including methicillin-resistant S. aureus (MRSA). Visible light-activated HTI also eliminate biofilms of S. aureus and B. subtilis in as little as 1 h after light activation. Quantification of reactive oxygen species (ROS) formation and protein carbonyls, as well as assays with various ROS scavengers, identifies oxidative damage as the underlying mechanism for the antibacterial activity of HTI. In addition to their direct antibacterial properties, HTI synergize with conventional antibiotics in vitro and in vivo, reducing the bacterial load and mortality associated with MRSA infection in an invertebrate burn wound model. To the best of the authors' knowledge, this is the first report on the antimicrobial activity of HTI-based molecular machines.

High-surface-area corundum nanoparticles by resistive hotspot-induced phase transformation

High-surface-area α-Al₂O₃ nanoparticles are used in high-strength ceramics and stable catalyst supports. The production of α-Al₂O₃ by phase transformation from γ-Al₂O₃ is hampered by a high activation energy barrier, which usually requires extended high-temperature annealing (~1500 K, > 10 h) and suffers from aggregation. Here, we report the synthesis of dehydrated α-Al₂O₃ nanoparticles (phase purity ~100%, particle size ~23 nm, surface area ~65 m² g^-1) by a pulsed direct current Joule heating of γ-Al₂O₃. The phase transformation is completed at a reduced bulk temperature and duration (~573 K, < 1 s) via an intermediate δ'-Al₂O₃ phase. Numerical simulations reveal the resistive hotspot-induced local heating in the pulsed current process enables the rapid transformation. Theoretical calculations show the topotactic transition (from γ- to δ'- to α-Al₂O₃) is driven by their surface energy differences. The α-Al₂O₃ nanoparticles are sintered to nanograined ceramics with hardness superior to commercial alumina and approaching that of sapphire.

Fragmenting nanoPutians: Capturing admiration to the rationality, predictability, and beauty of ion chemistry in mass spectrometry

The fragmentation chemistry of the protonated and ionized nanoPutian 1 has been studied in the gas phase via electrospray ionization and tandem mass spectrometry. A direct analogy was observed between the fragmentation chemistry of this fascinating "humanoid molecule" and "cleavages" at certain parts of the human body. We argue that such direct analogy and illustrative schemes for the fragmentation of molecular ions of 1 offer a ludic and efficient tool to teach and capture attention to ion chemistry in mass spectrometry. Using the changes in mass for the two heavier nanoPutians with different head styles but the same body design, the analogy has also been used to predict mass spectra. The concepts of isotopic labelling and dissociation thresholds have also been illustrated. For many years, the approach has been successfully used by one of us in classes and lectures, mainly when presenting ion chemistry to students and audiences from fields other than Chemistry, most particularly from Biology, Medicine, and Forensic Chemistry.

Robust Superhydrophobic Surfaces via the Sand-In Method

Superhydrophobic surfaces have gained sustained attention because of their extensive applications in the fields of self-cleaning, anti-icing, and drag reduction systems. Water droplets must have large apparent contact angle (CA) (>150°) and small CA hysteresis (<10°) on these surfaces. However, previous research usually involves complex fabrication strategies to modify the surface wettability. It is also challenging to maintain the temporal and mechanical stability of the delicate surface textures. Here, we develop a one-step solvent-free sand-in method to fabricate robust superhydrophobic surfaces directly atop various substrates with an apparent CA up to ∼163.8° and hysteresis less than 5°. The water repellency can withstand 100 Scotch tape peeling tests and remain stable after being stored under ambient humid conditions in Houston, Texas, for 18 months or being heated at 130 °C in air for 24 h. The superhydrophobic surfaces have excellent anti-icing ability, including a ∼2.6× longer water freezing time and ∼40% smaller ice adhesion strength with the temperature as low as -35 °C. Since the surface layers are fabricated by sanding the substrates with the powder additives, the surface damage can be repaired by a direct re-sanding treatment with the same powder additives. Further sand-in condition screenings broaden surface wettability from hydrophilic to superhydrophobic. The sand-in method induces the surface modification and the formation of the tribofilm. Surface and materials characterizations reveal that both microstructures and nanoscale asperities of the tribofilms contribute to the robust superhydrophobic features of sanded surfaces.

Brushed Metals for Rechargeable Metal Batteries

Battery designs are swiftly changing from metal-ion to rechargeable metal batteries. Theoretically, metals can deliver maximum anode capacity and enable cells with improved energy density. In practice, these advantages are only possible if the parasitic surface reactions associated with metal anodes are controlled. These undesirable surface reactions are responsible for many troublesome issues, like dendrite formation and accelerated consumption of active materials, which leads to anodes with low cycle life or even battery runaway. Here, a facile and solvent-free brushing method is reported to convert powders into films atop Li and Na metal foils. Benefiting from the reactivity of Li metal with these powder films, surface energy can be effectively tuned, thereby preventing parasitic reaction. In-operando study of P₂ S₅ -modified Li anodes in liquid electrolyte cells reveals a smoother electrode contour and more uniform metal electrodeposition and dissolution behavior. The P₂ S₅ -modified Li anodes sustain ultralow polarization in symmetric cell for >4000 h, ≈8× longer than bare Li anodes. The capacity retention is ≈70% higher when P₂ S₅ -modified Li anodes are paired with a practical LiFePO₄ cathode (≈3.2 mAh cm^-2 ) after 340 cycles. Brush coating opens a promising avenue to fabricate large-scale artificial solid-electrolyte-interphase directly on metals without the need for organic solvent.

Turbostratic Boron-Carbon-Nitrogen and Boron Nitride by Flash Joule Heating

Turbostratic layers in 2D materials have an interlayer misalignment. The lack of alignment expands the intrinsic interlayer distances and weakens the optical and electronic interactions between adjacent layers. This introduces properties distinct from those structures with well-aligned lattices and strong coupling interactions. However, direct and rapid synthesis of turbostratic materials remains a challenge owing to their thermodynamically metastable properties. Here, a flash Joule heating (FJH) method to achieve bulk synthesis of boron-carbon-nitrogen ternary compounds with turbostratic structures by a kinetically controlled ultrafast cooling process that takes place within milliseconds (10³  to 10⁴ K s^-1 ) is reported. Theoretical calculations support the existence of turbostratic structures and provide estimates of the energy barriers with respect to conversion into the corresponding well-aligned counterparts. When using non-carbon conductive additives, a direct synthesis of boron nitride is possible. The turbostratic nature facilitates mechanical exfoliation and more stable dispersions. Accordingly, the addition of flash products to a poly(vinyl alcohol) nanocomposite film coating a copper surface greatly improves the copper's resistance to corrosion in 0.5 m sulfuric acid or 3.5 wt% saline solution. FJH allows the use of bulk materials as reactants and provides a rapid approach to large quantities of the hitherto hard-to-access turbostratic materials.

Light-activated molecular machines are fast-acting broad-spectrum antibacterials that target the membrane

The increasing occurrence of antibiotic-resistant bacteria and the dwindling antibiotic research and development pipeline have created a pressing global health crisis. Here, we report the discovery of a distinctive antibacterial therapy that uses visible (405 nanometers) light-activated synthetic molecular machines (MMs) to kill Gram-negative and Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus, in minutes, vastly outpacing conventional antibiotics. MMs also rapidly eliminate persister cells and established bacterial biofilms. The antibacterial mode of action of MMs involves physical disruption of the membrane. In addition, by permeabilizing the membrane, MMs at sublethal doses potentiate the action of conventional antibiotics. Repeated exposure to antibacterial MMs is not accompanied by resistance development. Finally, therapeutic doses of MMs mitigate mortality associated with bacterial infection in an in vivo model of burn wound infection. Visible light-activated MMs represent an unconventional antibacterial mode of action by mechanical disruption at the molecular scale, not existent in nature and to which resistance development is unlikely.

Inverted Conformation Stability of a Motor Molecule on a Metal Surface

Molecular motors have been intensely studied in solution, but less commonly on solid surfaces that offer fixed points of reference for their motion and allow high-resolution single-molecule imaging by scanning probe microscopy. Surface adsorption of molecules can also alter the potential energy surface and consequently preferred intramolecular conformations, but it is unknown how this affects motor molecules. Here, we show how the different conformations of motor molecules are modified by surface adsorption using a combination of scanning tunneling microscopy and density functional theory. These results demonstrate how the contact of a motor molecule with a solid can affect the energetics of the molecular conformations.

Plastic Waste Product Captures Carbon Dioxide in Nanometer Pores

Plastic waste (PW) and increasing atmospheric carbon dioxide (CO₂) levels are among the top environmental concerns presently facing humankind. With an ambitious 2050 zero-CO₂ emissions goal, there is a demand for economical CO₂ capture routes. Here we show that the thermal treatment of PW in the presence of potassium acetate yields an effective carbon sorbent with pores width of 0.7-1.4 nm for CO₂ capture. The PW to carbon sorbent process works with single or mixed streams of polyolefin plastics. The CO₂ capacity of the sorbent at 25 °C is 17.0 ± 1.1 wt % (3.80 ± 0.25 mmol g^-1) at 1 bar and 5.0 ± 0.6 wt % (1.13 ± 0.13 mmol g^-1) at 0.15 bar, and it regenerates upon reaching 75 ± 5 °C. The CO₂ capture cost from flue gas via this technology is estimated to be <$21 ton^-1 CO₂, much lower than competing CO₂ capture technologies. Hence, this PW-derived carbon material should find utility in the capture of CO₂ from point sources of high CO₂ emissions while providing a use for otherwise deleterious PW.

Holey and Wrinkled Flash Graphene from Mixed Plastic Waste

High surface area varieties of graphene have captured significant attention, allowing for improved performance in a variety of applications. However, there are challenges facing the use of graphene in these applications since it is expensive and difficult to synthesize in bulk. Here, we leverage the capabilities of flash Joule heating to synthesize holey and wrinkled flash graphene (HWFG) in seconds from mixed plastic waste feedstocks, using in situ salt decomposition to produce and stabilize pore formation during the reaction. Surface areas as high as 874 m² g^-1 are obtained, with characteristics of micro-, meso-, and macroporosities. Raman spectroscopy confirms the wrinkled and turbostratic nature of the HWFG. We demonstrate HWFG applications in its use as a metal-free hydrogen evolution reaction electrocatalyst, with excellent stability, competitive overpotential, and Tafel slope; in a Li-metal battery anode allowing for stable and high discharge rates; and in a material with high gas adsorption. This represents an upcycle of mixed plastic waste, thereby affording a valuable route to address this pressing environmental pollutant concern.

Heteroatom-Doped Flash Graphene

Heteroatom doping can effectively tailor the local structures and electronic states of intrinsic two-dimensional materials, and endow them with modified optical, electrical, and mechanical properties. Recent studies have shown the feasibility of preparing doped graphene from graphene oxide and its derivatives via some post-treatments, including solid-state and solvothermal methods, but they require reactive and harsh reagents. However, direct synthesis of various heteroatom-doped graphene in larger quantities and high purity through bottom-up methods remains challenging. Here, we report catalyst-free and solvent-free direct synthesis of graphene doped with various heteroatoms in bulk via flash Joule heating (FJH). Seven types of heteroatom-doped flash graphene (FG) are synthesized through millisecond flashing, including single-element-doped FG (boron, nitrogen, oxygen, phosphorus, sulfur), two-element-co-doped FG (boron and nitrogen), as well as three-element-co-doped FG (boron, nitrogen, and sulfur). A variety of low-cost dopants, such as elements, oxides, and organic compounds are used. The graphene quality of heteroatom-doped FG is high, and similar to intrinsic FG, the material exhibits turbostraticity, increased interlayer spacing, and superior dispersibility. Electrochemical oxygen reduction reaction of different heteroatom-doped FG is tested, and sulfur-doped FG shows the best performance. Lithium metal battery tests demonstrate that nitrogen-doped FG exhibits a smaller nucleation overpotential compared to Cu or undoped FG. The electrical energy cost for the synthesis of heteroatom-doped FG synthesis is only 1.2 to 10.7 kJ g^-1, which could render the FJH method suitable for low-cost mass production of heteroatom-doped graphene.

Atomic Molybdenum for Synthesis of Ammonia with 50% Faradic Efficiency

The electrochemical dinitrogen (N₂ ) reduction reaction (NRR) under ambient conditions has gained significant interest as an environmentally friendly alternative to the traditional Haber-Bosch process for the synthesis of ammonia (NH₃ ). However, up to now, most of the reported NRR electrocatalysts with satisfactory catalytic activities have been hindered by the large overpotential in N₂ activation. The preparation of highly efficient Mo-based NRR electrocatalyst in acidic electrolytes under ambient conditions is demonstrated here, consisting of stabilized single Mo atoms anchored on holey nitrogen-doped graphene synthesized through a convenient potassium-salt-assisted activation method. At -0.05 V versus a reversible hydrogen electrode (RHE), an electrode consisting of the resultant electrocatalyst immobilized on carbon fiber paper can attain an exceptional Faradaic efficiency of 50.2% and a NH₃ yield rate of 3.6 µg h^-1 mg_cat^-1 with low overpotentials. Density functional theory calculations further unveil that compared to the original graphene without holes, the edge coordinated Mo atoms and the existence of vacancies on holey graphene lower the overpotential of N₂ reduction, thereby promoting the NRR catalytic activity. This work could provide new guidelines for future designs in single-atom catalysis that would be beneficial to ambient N₂ fixation, and replacement of classical synthesis processes that are very energy-intensive.

Machine Learning Guided Synthesis of Flash Graphene

Advances in nanoscience have enabled the synthesis of nanomaterials, such as graphene, from low-value or waste materials through flash Joule heating. Though this capability is promising, the complex and entangled variables that govern nanocrystal formation in the Joule heating process remain poorly understood. In this work, machine learning (ML) models are constructed to explore the factors that drive the transformation of amorphous carbon into graphene nanocrystals during flash Joule heating. An XGBoost regression model of crystallinity achieves an r² score of 0.8051 ± 0.054. Feature importance assays and decision trees extracted from these models reveal key considerations in the selection of starting materials and the role of stochastic current fluctuations in flash Joule heating synthesis. Furthermore, partial dependence analyses demonstrate the importance of charge and current density as predictors of crystallinity, implying a progression from reaction-limited to diffusion-limited kinetics as flash Joule heating parameters change. Finally, a practical application of the ML models is shown by using Bayesian meta-learning algorithms to automatically improve bulk crystallinity over many Joule heating reactions. These results illustrate the power of ML as a tool to analyze complex nanomanufacturing processes and enable the synthesis of 2D crystals with desirable properties by flash Joule heating.

Rare earth elements from waste

Rare earth elements (REEs) are critical materials in electronics and clean technologies. With the diminishing of easily accessible minerals for mining, the REE recovery from waste is an alternative toward a circular economy. Present methods for REE recovery suffer from lengthy purifications, low extractability, and high wastewater streams. Here, we report an ultrafast electrothermal process (~3000°C, ~1 s) based on flash Joule heating (FJH) for activating wastes to improve REE extractability. FJH thermally degrades or reduces the hard-to-dissolve REE species to components with high thermodynamic solubility, leading to ~2× increase in leachability and high recovery yields using diluted acid (e.g., 0.1 M HCl). The activation strategy is feasible for various wastes including coal fly ash, bauxite residue, and electronic waste. The rapid FJH process is energy-efficient with a low electrical energy consumption of 600 kWh ton^-1. The potential for this route to be rapidly scaled is outlined.

Abstract WP253: Increased Hydrogen Sulfide As A New Mechanism For Hyperglycemic Worsening Of Stroke Outcome

Introduction: Hyperglycemia at stroke onset worsens outcome and reduces the effectiveness of reperfusion therapies. Increased oxidative and mitochondrial injury likely contribute. To treat this mechanism, we synthesized (PEG)-ylated carbon nanoparticles (CNPs) from acid oxidation of activated charcoal (OAC) generating 3 nm discs, catalytic superoxide dismutase mimetics that protect mitochondrial complexes. Cellular uptake is rapid and delayed I.V. PEG-CNPs are highly protective in reversible MCAO in hyperglycemic rats. Hydrogen sulfide (H 2 S) is an essential gaseous transmitter with a narrow therapeutic index associated with many disorders e.g., diabetes. Its synthesis is influenced by radicals. Excess H 2 S is toxic to mitochondrial complex IV. H 2 S is endogenously oxidized to polysulfides (PS), potent antioxidants also needed for protein persulfidation. We hypothesized that OAC’s favorable redox potential will catalyze H 2 S oxidization to PS, acute hyperglycemia will increase H 2 S and PEG-OACs will blunt the increase.

Methods: b.End3 brain endothelial and HEK293 cultured cells were employed. SSP4 fluorescence measured PS levels with increasing concentrations of PEG-OACs. AzMC fluorescence detected H 2 S levels in cells incubated in 100 mg/dL glucose media followed by glucose 500 mg/dL with or without PEG-OACs, first in normoxia followed by anoxia/normoxia.

Results: PEG-OACs dose dependently increased cellular PS levels (Fig 1a). High glucose increased H 2 S levels especially during anoxia/normoxia (Fig 1b). PEG-OACs completely eliminated the glucose-induced increase in H 2 S (Fig 1c).

Conclusions: Acute hyperglycemia increased H 2 S production especially under conditions mimicking ischemia/reperfusion, an effect eliminated by PEG-OACs. Because of mitochondrial toxicity, an H 2 S increase may contribute to worsened outcome in hyperglycemic stroke. These results suggest a new therapeutic target for this important cause of poor stroke outcome.

Large-Scale Syntheses of 2D Materials: Flash Joule Heating and Other Methods

In the past 17 years, the larger-scale production of graphene and graphene family materials has proven difficult and costly, thus slowing wider-scale commercial applications. The quality of the graphene that is prepared on larger scales has often been poor, demonstrating a need for improved quality controls. Here, current industrial graphene synthetic and analytical methods, as well as recent academic advancements in larger-scale or sustainable synthesis of graphene, defined here as weights more than 200 mg or films larger than 200 cm² , are compiled and reviewed. There is a specific emphasis on recent research in the use of flash Joule heating as a rapid, efficient, and scalable method to produce graphene and other 2D nanomaterials. Reactor design, synthetic strategies, safety considerations, feedstock selection, Raman spectroscopy, and future outlooks for flash Joule heating syntheses are presented. To conclude, the remaining challenges and opportunities in the larger-scale synthesis of graphene and a perspective on the broader use of flash Joule heating for larger-scale 2D materials synthesis are discussed.

Phase controlled synthesis of transition metal carbide nanocrystals by ultrafast flash Joule heating

Nanoscale carbides enhance ultra-strong ceramics and show activity as high-performance catalysts. Traditional lengthy carburization methods for carbide syntheses usually result in coked surface, large particle size, and uncontrolled phase. Here, a flash Joule heating process is developed for ultrafast synthesis of carbide nanocrystals within 1 s. Various interstitial transition metal carbides (TiC, ZrC, HfC, VC, NbC, TaC, Cr2C3, MoC, and W2C) and covalent carbides (B4C and SiC) are produced using low-cost precursors. By controlling pulse voltages, phase-pure molybdenum carbides including β-Mo2C and metastable α-MoC1-x and η-MoC1-x are selectively synthesized, demonstrating the excellent phase engineering ability of the flash Joule heating by broadly tunable energy input that can exceed 3000 K coupled with kinetically controlled ultrafast cooling (>104 K s-1). Theoretical calculation reveals carbon vacancies as the driving factor for topotactic transition of carbide phases. The phase-dependent hydrogen evolution capability of molybdenum carbides is investigated with β-Mo2C showing the best performance.

The Future of Flash Graphene for the Sustainable Management of Solid Waste

Graphene research has steadily increased, and its commercialization in many applications is becoming a reality because of its superior physicochemical properties and advances in synthesis techniques. However, bulk-scale production of graphene still requires large amounts of solvents, electrochemical treatment, or sonication. Recently, a method was discovered to convert bulk quantities of carbonaceous materials to graphene using flash Joule heating (FJH) and, so named, flash graphene (FG). This method can be used to turn various solid wastes containing the prerequisite element carbon into FG. Globally, more than 2 billion tons of municipal solid waste (MSW) are generated every year and, in many municipalities, are becoming unmanageable. The most commonly used waste management methods include recycling, composting, anaerobic digestion, incineration, gasification, pyrolysis, and landfill disposal. However, around 70% of global waste ends up in landfills or open dumps, while the rest is recycled, composted, or incinerated. Even the various waste valorization techniques, such as pyrolysis and gasification, produce some waste residues that have their ultimate destination in landfills. Thus, technologies that can minimize waste volume or convert waste into valuable products are required. The thermal treatment process of FJH for FG production provides both waste volume reduction and valorization in the form of FG. In this Perspective, we provide an overview of FJH and its possible applications in various types of waste conversion/valorization. We describe the typical current MSW management system as well as the potential for creating FG at various stages and propose a schematic plan for the incorporation of FG in MSW management. We also analyze the strengths, weaknesses, opportunities, and threats of MSW as an FG precursor in terms of technical, economic, environmental, and social sustainability. This valuable waste valorization and management strategy can help achieve near-zero waste and an economy-boosting MSW management system.