Electrochemical Lensing for High Resolution Nanostructure Synthesis in Liquids.

The advancement of liquid phase electron/ion beam induced deposition has enabled an effective direct-write approach for functional nanostructure synthesis with the possibility of three-dimensional control of morphology. For formation of a metallic solid phase, the process employs ambient temperature, beam-guided, electrochemical reduction of precursor cations, resulting in rapid formation of structures, but with challenges for retention of resolution achievable via slower electron beam approaches. The possibility of spatial control of redox pathways via the use of water-ammonia solvents has opened avenues for improved nanostructure resolution without sacrificing the growth rate. In particular, ammonia enables "electrochemical lensing" in which a tightly confined and highly reducing environment is created locally to enable high resolution, rapid beam-directed nanostructure growth. We demonstrate this unique approach to high resolution synthesis through a combination of analysis and experiment.

Microfluidics enabled multi-omics triple-shot mass spectrometry for cell-based therapies.

In recent years, cell-based therapies have transformed medical treatment. These therapies present a multitude of challenges associated with identifying the mechanism of action, developing accurate safety and potency assays, and achieving low-cost product manufacturing at scale. The complexity of the problem can be attributed to the intricate composition of the therapeutic products: living cells with complex biochemical compositions. Identifying and measuring critical quality attributes (CQAs) that impact therapy success is crucial for both the therapy development and its manufacturing. Unfortunately, current analytical methods and tools for identifying and measuring CQAs are limited in both scope and speed. This Perspective explores the potential for microfluidic-enabled mass spectrometry (MS) systems to comprehensively characterize CQAs for cell-based therapies, focusing on secretome, intracellular metabolome, and surfaceome biomarkers. Powerful microfluidic sampling and processing platforms have been recently presented for the secretome and intracellular metabolome, which could be implemented with MS for fast, locally sampled screening of the cell culture. However, surfaceome analysis remains limited by the lack of rapid isolation and enrichment methods. Developing innovative microfluidic approaches for surface marker analysis and integrating them with secretome and metabolome measurements using a common analytical platform hold the promise of enhancing our understanding of CQAs across all "omes," potentially revolutionizing cell-based therapy development and manufacturing for improved efficacy and patient accessibility.

Direct evidence of substorm-related impulsive injections of electrons at Mercury.

Mercury's magnetosphere is known to involve fundamental processes releasing particles and energy like at Earth due to the solar wind interaction. The resulting cycle is however much faster and involves acceleration, transport, loss, and recycling of plasma. Direct experimental evidence for the roles of electrons during this cycle is however missing. Here we show that in-situ plasma observations obtained during BepiColombo's first Mercury flyby reveal a compressed magnetosphere hosts of quasi-periodic fluctuations, including the original observation of dynamic phenomena in the post-midnight, southern magnetosphere. The energy-time dispersed electron enhancements support the occurrence of substorm-related, multiple, impulsive injections of electrons that ultimately precipitate onto its surface and induce X-ray fluorescence. These observations reveal that electron injections and subsequent energy-dependent drift now observed throughout Solar System is a universal mechanism that generates aurorae despite the differences in structure and dynamics of the planetary magnetospheres.

Forecasting Heliospheric CME Solar-Wind Parameters Using the UCSD Time-Dependent Tomography and ISEE Interplanetary Scintillation Data: The 10 March 2022 CME.

Remotely sensed interplanetary scintillation (IPS) data from the Institute for Space-Earth Environmental Research (ISEE), Japan, allows a determination of solar-wind parameters throughout the inner heliosphere. We show the 3D analysis technique developed for these data sets that forecast plasma velocity, density, and component magnetic fields at Earth, as well at the other inner heliospheric planets and spacecraft. One excellent coronal mass ejection (CME) example that occurred on the 10 March 2022 was viewed not only in the ISEE IPS analyses, but also by the spacecraft near Earth that measured the CME arrival at one AU. Solar Orbiter, that was nearly aligned along the Earth radial at 0.45 AU, also measured the CME in plasma density, velocity, and magnetic field. BepiColombo at 0.42 AU was also aligned with the STEREO A spacecraft, and viewed this CME. The instruments used here from BepiColombo include: 1) the European-Space-Agency Mercury-Planetary-Orbiter magnetic field measurements; 2) the Japan Aerospace Exploration Agency Mio spacecraft Solar Particle Monitor that viewed the CME Forbush decrease, and the Mercury Plasma Experiment/Mercury Electron Analyzer instruments that measured particles and solar-wind density from below the spacecraft protective sunshield covering. This article summarizes the analysis using ISEE, Japan real-time data for these forecasts: it provides a synopsis of the results and confirmation of the CME event morphology after its arrival, and discusses how future IPS analyses can augment these results.

Early detection and metabolic pathway identification of T cell activation by in-process intracellular mass spectrometry.

BACKGROUND AIMS: In-process monitoring and control of biomanufacturing workflows remains a significant challenge in the development, production, and application of cell therapies. New process analytical technologies must be developed to identify and control the critical process parameters that govern ex vivo cell growth and differentiation to ensure consistent and predictable safety, efficacy, and potency of clinical products. METHODS: This study demonstrates a new platform for at-line intracellular analysis of T-cells. Untargeted mass spectrometry analyses via the platform are correlated to conventional methods of T-cell assessment. RESULTS: Spectral markers and metabolic pathways correlated with T-cell activation and differentiation are detected at early time points via rapid, label-free metabolic measurements from a minimal number of cells as enabled by the platform. This is achieved while reducing the analytical time and resources as compared to conventional methods of T-cell assessment. CONCLUSIONS: In addition to opportunities for fundamental insight into the dynamics of T-cell processes, this work highlights the potential of in-process monitoring and dynamic feedback control strategies via metabolic modulation to drive T-cell activation, proliferation, and differentiation throughout biomanufacturing.

Predicting brain temperature in humans using bioheat models: Progress and outlook.

Brain temperature, regulated by the balance between blood circulation and metabolic heat generation, is an important parameter related to neural activity, cerebral hemodynamics, and neuroinflammation. A key challenge for integrating brain temperature into clinical practice is the lack of reliable and non-invasive brain thermometry. The recognized importance of brain temperature and thermoregulation in both health and disease, combined with limited availability of experimental methods, has motivated the development of computational thermal models using bioheat equations to predict brain temperature. In this mini-review, we describe progress and the current state-of-the-art in brain thermal modeling in humans and discuss potential avenues for clinical applications.

Comparisons of healthy human brain temperature predicted from biophysical modeling and measured with whole brain MR thermometry.

Brain temperature is an understudied parameter relevant to brain injury and ischemia. To advance our understanding of thermal dynamics in the human brain, combined with the challenges of routine experimental measurements, a biophysical modeling framework was developed to facilitate individualized brain temperature predictions. Model-predicted brain temperatures using our fully conserved model were compared with whole brain chemical shift thermometry acquired in 30 healthy human subjects (15 male and 15 female, age range 18-36 years old). Magnetic resonance (MR) thermometry, as well as structural imaging, angiography, and venography, were acquired prospectively on a Siemens Prisma whole body 3 T MR scanner. Bland-Altman plots demonstrate agreement between model-predicted and MR-measured brain temperatures at the voxel-level. Regional variations were similar between predicted and measured temperatures (< 0.55 °C for all 10 cortical and 12 subcortical regions of interest), and subcortical white matter temperatures were higher than cortical regions. We anticipate the advancement of brain temperature as a marker of health and injury will be facilitated by a well-validated computational model which can enable predictions when experiments are not feasible.

Altering apparent optical properties with an array of semitransparent mesoscale structures.

The ability to control and optimize interactions between light and matter has much utility in engineering design. A well-researched way to achieve optical property modulation is via the use of optical metamaterials, which feature sub-wavelength scale surface structures. In this work, an alternative approach for modulating optical properties is presented using a composite surface modified with a periodic array of semitransparent hemispherical shell mesoscale structures which are larger than the incident light wavelength. A ray-tracing simulation approach is used to predict the optical behavior for an arrayed surface. At oblique angles of incidence, significant increases and decreases in apparent absorptance are achieved via the use of optically thick and thin shells, respectively. Additionally, a potential application to solar cells is described with optimal spectral behavior achieved via the use of semitransparent external structures.

Integrated photoelectrochemical energy storage cells prepared by benchtop ion soft landing.

The exceptional photochromic and redox properties of polyoxometalate anions, PW12O403-, have been exploited to develop an integrated photoelectrochemical energy storage cell for conversion and storage of solar energy. Elimination of strongly coordinating cations using benchtop ion soft landing leads to a ∼370% increase in the maximum power output of the device. Additionally, the photocathode displayed a pronounced color change from clear to blue upon irradiation, which warrants the potential application of the IPES cell in advanced smart windows and photochromic lenses.

Radiolytic redox interplay defines nanomaterial synthesis in liquids.

Irradiation of a liquid solution generates solvated electrons and radiolysis products, which can lead to material deposition or etching. The chemical environment dictates the dominant reactions. Radiolysis-induced reactions in salt solutions have substantially different results in pure water versus water-ammonia, which extends the lifetime of solvated electrons. We investigate the interplay between transport and solution chemistry via the example of solid silver formation from e-beam irradiation of silver nitrate solutions in water and water-ammonia. The addition of ammonia results in the formation of a secondary ring-shaped deposit tens of micrometers in diameter (formed over tens of seconds) around the primary point of deposition (formed over milliseconds). Simulations uncover the relative importance of oxidizing and reducing reactions and transport effects. Our explanation of this behavior involves mechanisms beyond ammonia's role in extending solvated electron lifetimes.

Sample-to-analysis platform for rapid intracellular mass spectrometry from small numbers of cells.

Real-time, advanced diagnostics of the biochemical state within cells remains a significant challenge for research and development, production, and application of cell-based therapies. The fundamental biochemical processes and mechanisms of action of such advanced therapies are still largely unknown, including the critical quality attributes that correlate to therapeutic function, performance, and potency and the critical process parameters that impact quality throughout cell therapy manufacturing. An integrated microfluidic platform has been developed for in-line analysis of a small number of cells via direct infusion nano-electrospray ionization mass spectrometry. Central to this platform is a microfabricated cell processing device that prepares cells from limited sample volumes removed directly from cell culture systems. The sample-to-analysis workflow overcomes the labor intensive, time-consuming, and destructive nature of existing mass spectrometry approaches for analysis of cells. By providing rapid, high-throughput analyses of the intracellular state, this platform enables untargeted discovery of critical quality attributes and their real-time, in-process monitoring.

Nanoscale Engineering of Inorganic Composite Scintillation Materials.

This review article considers the latest developments in the field of inorganic scintillation materials. Modern trends in the improvement of inorganic scintillation materials are based on engineering their features at the nanoscale level. The essential challenges to the fundamental steps of the technology of inorganic glass, glass ceramics, and ceramic scintillation materials are discussed. The advantage of co-precipitation over the solid-state synthesis of the raw material compositions, particularly those which include high vapor components is described. Methods to improve the scintillation parameters of the glass to the level of single crystals are considered. The move to crystalline systems with the compositional disorder to improve their scintillation properties is justified both theoretically and practically. A benefit of the implementation of the discussed matters into the technology of well-known glass and crystalline scintillation materials is demonstrated.

Localized Sampling Enables Monitoring of Cell State via Inline Electrospray Ionization Mass Spectrometry.

Nascent advanced therapies, including regenerative medicine and cell and gene therapies, rely on the production of cells in bioreactors that are highly heterogeneous in both space and time. Unfortunately, advanced therapies have failed to reach a wide patient population due to unreliable manufacturing processes that result in batch variability and cost prohibitive production. This can be attributed largely to a void in existing process analytical technologies (PATs) capable of characterizing the secreted critical quality attribute (CQA) biomolecules that correlate with the final product quality. The Dynamic Sampling Platform (DSP) is a PAT for cell bioreactor monitoring that can be coupled to a suite of sensor techniques to provide real-time feedback on spatial and temporal CQA content in situ. In this study, DSP is coupled with electrospray ionization mass spectrometry and direct-from-culture sampling to obtain measures of CQA content in bulk media and the cell microenvironment throughout the entire cell culture process (≈3 weeks). Post hoc analysis of this real-time data reveals that sampling from the microenvironment enables cell state monitoring (e.g., confluence, differentiation). These results demonstrate that an effective PAT should incorporate both spatial and temporal resolution to serve as an effective input for feedback control in biomanufacturing.

Hydrodynamics of Vortical Gas Jets Coupled to Point-Like Suction.

Vortical jet flows in the Reynolds number (Re) range from 1000 to 3425 and swirl number (S) below 0.5, alone and in combination with suction through a small aperture, are experimentally investigated using optical visualization. Schlieren photography is employed to assess the vortical flow structure and establish the fundamental understanding of the source-to-sink gas-dynamic coupling, including the role played by flow rate, jet diameter, and the separation distance between the gas jet source and the suction sink. Compared to vortex-free jets, vortical jets for Re>2700 with swirl number S>0.27 experience earlier laminar-to-turbulent transition, with resulting rapid growth of the jet boundary. The ability to control growth of the jet expansion and mass and momentum dissipation into the surrounding is demonstrated via use of a coaxially aligned flow suction placed in the path of a jet. When a swirling jet is completely coupled with a flow suction, jet expansion is significantly suppressed. The suction/sink flow rate imposes a limit on the maximum input/source flow rate of gas jet to achieve complete coupling. Furthermore, there is a maximum distance over which effective coupling can occur, and for all Reynolds numbers considered this distance is shorter than the distance at which the jet structure breaks up into turbulent eddies in the absence of a sink.

Electrohydrodynamics of Gas-Assisted Electrospray Ionization Mass Spectrometry.

Gas-flow assistance is commonly used in ESI-MS for improved transport and desolvation, and fundamental understanding of the underlying phenomena is essential for improvement of aerodynamic interfaces that couple ESI sources and MS. For this purpose, an electrohydrodynamic model is developed for simulation of charged droplet dynamics under the combined effects of gas flow and electric fields with consideration of space charge interactions within the charged aerosol plume. The model is implemented in COMSOL by exploiting a formalism for establishing the droplet trajectories as a sequence of successive droplets ejected at a frequency defined by the electrospray current. The model is used to assess the effect of two distinct flow configurations and compared to the baseline care of electrospray without assist gas. The simulated flows are jet flows oriented coaxially with the ESI spray, with and without imposed vorticity (swirling). Droplet trajectory simulations of a bimodal droplet population consisting of large primary droplets and small progeny droplets reveal a unique capability for vortical assist jet flow to selectively transmit smaller droplets into the MS due to inertial separation. ESI-MS analysis of fluorinated phosphazines subjected to the different gas flow conditions supports the model predictions. The electrohydrodynamic model developed in this work provides a versatile tool to analyze and design aerodynamic ESI interfaces with rigorous incorporation of drag, inertia, and space-charge repulsion and can be used as a powerful simulation methodology for optimizing charged droplet transmission and ultimately improved analytical performance of gas-assisted ESI-MS workflows.

High-Resolution Three-Dimensional Sculpting of Two-Dimensional Graphene Oxide by E-Beam Direct Write.

On-demand switchable "additive/subtractive" patterning of two-dimensional (2D) nanomaterials is an essential capability for developing new concepts of functional nanomaterials and their device realizations. Traditionally, this is performed via a multistep process using photoresist coating and patterning by conventional photo or electron beam lithography, which is followed by bulk dry/wet etching or deposition. This limits the range of functionalities and structural topologies that can be achieved as well as increases the complexity, cost, and possibility of contamination, which are significant barriers to device fabrication from highly sensitive 2D materials. Focused electron beam-induced processing (FEBIP) enables a material chemistry/site-specific, high-resolution multimode atomic scale processing and provides unprecedented opportunities for "direct-write", single-step surface patterning of 2D nanomaterials with an in situ imaging capability. It allows for realizing a rapid multiscale/multimode approach, ranging from an atomic scale manipulation (e.g., via targeted defect introduction as an active site) to a large-area surface modification on nano- and microscales, including patterned doping and material removal/deposition with 2D (in-plane)/three-dimensional (3D) (out-of-plane) control. In this work, we report on a new capability of FEBIP for nanoscale patterning of graphene oxide via removal of oxygenated carbon moieties with no use of reactive gas required for etching complemented by carbon atom deposition using a focused electron beam. The mechanism of experimentally observed phenomena is explored using the density functional theory (DFT) calculations, revealing that interactions of e-beam that liberated reactive oxygen radicals with carbon atoms on the graphene basal plane lead to the creation of atomic vacancies in the material. The reaction byproducts are volatile carbon dioxides, which are dissociated and volatilized from the graphene oxide surface functional groups by interactions with an energetic focused electron beam. Along with selective subtractive patterning of graphene oxide, the same electron beam with increased irradiation doses can deposit out-of-plane 3D carbon nanostructures on top of or around the 2D etched pattern, thus forming a hybrid 2D/3D nanocomposite with a feature control down to a few nanometers. This in operando dual nanofabrication capability of FEBIP is unmatched by any other nanopatterning techniques and opens a new design window for forming 2D/3D complex nanostructures and functional nanodevices.

Non-equilibrium adatom thermal state enables rapid additive nanomanufacturing.

A new state of radical thermal non-equilibrium in surface adsorbed molecules is discovered that enables rapid surface diffusion of energized adatoms with a negligible effect on the substrate surface temperature. Due to enhanced surface diffusion, growth rates can be achieved that improve the feasibility of many nanofabrication techniques. Since the adatom temperature cannot be directly measured without disturbing its thermodynamic state, the first principle hard-cube model is used to predict both the adatom effective temperature and the surface temperature in response to gaseous particle impingement in a vacuum. The validity of the approach is supported by local, spatially-resolved surface temperature measurements of the thermal response to supersonic microjet gas impingement. The ability to determine and control the adatom effective temperature, and therefore the surface diffusion rate, opens new degrees of freedom in controlling a wide range of nanofabrication processes that critically depend on surface diffusion of precursor molecules. This fundamental understanding has the potential to accelerate research into nanoscale fabrication and to yield the new materials with unique properties that are only accessible with nanoscale features.

Dynamic mass spectrometry probe for electrospray ionization mass spectrometry monitoring of bioreactors for therapeutic cell manufacturing.

Large-scale manufacturing of therapeutic cells requires bioreactor technologies with online feedback control enabled by monitoring of secreted biomolecular critical quality attributes (CQAs). Electrospray ionization mass spectrometry (ESI-MS) is a highly sensitive label-free method to detect and identify biomolecules, but requires extensive sample preparation before analysis, making online application of ESI-MS challenging. We present a microfabricated, monolithically integrated device capable of continuous sample collection, treatment, and direct infusion for ESI-MS detection of biomolecules in high-salt solutions. The dynamic mass spectrometry probe (DMSP) uses a microfluidic mass exchanger to rapidly condition samples for online MS analysis by removing interfering salts, while concurrently introducing MS signal enhancers to the sample for sensitive biomolecular detection. Exploiting this active conditioning capability increases MS signal intensity and signal-to-noise ratio. As a result, sensitivity for low-concentration biomolecules is significantly improved, and multiple proteins can be detected from chemically complex samples. Thus, the DMSP has significant potential to serve as an enabling portion of a novel analytical tool for discovery and monitoring of CQAs relevant to therapeutic cell manufacturing.

Enhanced intracellular delivery via coordinated acoustically driven shear mechanoporation and electrophoretic insertion.

Delivery of large and structurally complex target molecules into cells is vital to the emerging areas of cellular modification and molecular therapy. Inadequacy of prevailing in vivo (viral) and in vitro (liposomal) gene transfer methods for delivery of proteins and a growing diversity of synthetic nanomaterials has encouraged development of alternative physical approaches. Efficacy of injury/diffusion-based delivery via shear mechanoporation is largely insensitive to cell type and target molecule; however, enhanced flexibility is typically accompanied by reduced gene transfer effectiveness. We detail a method to improve transfection efficiency through coordinated mechanical disruption of the cell membrane and electrophoretic insertion of DNA to the cell interior. An array of micromachined nozzles focuses ultrasonic pressure waves, creating a high-shear environment that promotes transient pore formation in membranes of transmitted cells. Acoustic Shear Poration (ASP) allows passive cytoplasmic delivery of small to large nongene macromolecules into established and primary cells at greater than 75% efficiency. Addition of an electrophoretic action enables active transport of target DNA molecules to substantially augment transfection efficiency of passive mechanoporation/diffusive delivery without affecting viability. This two-stage poration/insertion method preserves the compelling flexibility of shear-based delivery, yet substantially enhances capabilities for active transport and transfection of plasmid DNA.

DRILL Interface Makes Ion Soft Landing Broadly Accessible for Energy Science and Applications.

Polyoxometalates (POM) have been deposited onto carbon nanotube (CNT) electrodes using benchtop ion soft landing (SL) enabled by a vortex-confined electrohydrodynamic desolvation process. The device is based on the dry ion localization and locomotion (DRILL) mass spectrometry interface of Fedorov and co-workers. By adding electrospray emitters, heating the desolvation gas, and operating at high gas flow rates, it is possible to obtain stable ion currents up to -15 nA that are ideal for deposition. Coupled with ambient ion optics, this interface enables desolvated ions to be delivered to surfaces while excluding solvent and counterions. Electron microscopy of surfaces prepared using the device reveal discrete POM and no aggregation that degrades electrode performance. Characterization of POM-coated CNT electrodes in a supercapacitor showed an energy storage capacity similar to that achieved with SL in vacuum. For solutions that produce primarily a single ion by electrospray ionization, benchtop SL offers a simpler and less costly approach for surface modification with applications in catalysis, energy storage, and beyond.