Reflection Microscopy Research Articles

Multipole engineering by displacement resonance: a new degree of freedom of Mie resonance

The canonical studies on Mie scattering unravel strong electric/magnetic optical responses in nanostructures, laying foundation for emerging meta-photonic applications. Conventionally, the morphology-sensitive resonances hinge on the normalized frequency, i.e. particle size over wavelength, but non-paraxial incidence symmetry is overlooked. Here, through confocal reflection microscopy with a tight focus scanning over silicon nanostructures, the scattering point spread functions unveil distinctive spatial patterns featuring that linear scattering efficiency is maximal when the focus is misaligned. The underlying physical mechanism is the excitation of higher-order multipolar modes, not accessible by plane wave irradiation, via displacement resonance, which showcases a significant reduction of nonlinear response threshold, sign flip in all-optical switching, and spatial resolution enhancement. Our result fundamentally extends the century-old light scattering theory, and suggests new dimensions to tailor Mie resonances.

Abstract 14438: Loss of the ROR2 Tyrosine Kinase Receptor is Associated With Dysfunctional Angiogenesis in Pulmonary Hypertension via Inappropriate Focal Adhesion Activation and Disruption of the Endothelial Barrier

Background: Dysfunctional angiogenesis is a hallmark of pulmonary arterial hypertension (PAH), but its mechanisms are unclear. We recently demonstrated a key role for Wnt7a in lung angiogenesis. Wnt7a acts through ROR2, a Wnt pathway tyrosine kinase receptor. We elucidate how ROR2 controls angiogenic functions in pulmonary microvascular endothelial cells (PMVECs). Hypothesis: Loss of ROR2 activity is associated with PAH. Methods: Healthy and PAH PMVECs were obtained from explanted lungs. PMVECs were transfected with ROR2 siRNA/constructs, followed by functional and molecular studies. Focal adhesion (FA) activation and force generation was measured using FRET-based total internal reflection microscopy (TIRF). Mice with endothelial-specific conditional ROR2 KO (ROR2 ECKO) were phenotyped in normoxia and hypoxia. Results: ROR2 expression was found predominantly in the endothelium of healthy lung vessels but significantly reduced within PAH lesions. ROR2 knockdown (siROR2) reduced vascular sprouting comparable to PAH PMVECs. Interestingly, siROR2 and ROR2-deficient PAH PMVECs displayed increased fibronectin adhesion and hyperpermeability, which led us to look at focal adhesions (FA) and cell-cell junctions. Confocal and TIRF microscopy of siROR2 and ROR2-deficient PAH PMVECs revealed an increase in the FA number and force that inversely correlated with reduced VE-cadherin at cell junctions. However, transfection of a ROR2 construct in PAH PMVECs resulted in FAs activity normalization and junctional integrity accompanied by recovery of adhesion and permeability. Proteomic studies demonstrated that ROR2 interacts with Integrin b1 in focal adhesions, and its loss results in Integrin b1 activation, FA clustering, and high mechanical forces. In animal studies, we found that, compared to controls, ROR2 ECKO developed more severe pulmonary hypertension, right ventricular remodeling, microvascular reduction, and muscularization in hypoxia, which correlated with higher levels of integrin b1 activation and reduced VE-cadherin expression. Conclusions: ROR2 promotes PMVEC adhesion and barrier formation, and its loss is associated with dysfunctional angiogenesis. Restoring ROR2 could be a novel therapeutic strategy in PAH.

Operando Surface Optical Reflectance Microscopy Study of Corrosion Film Growth on a Ni–Cr–Mo Alloy During Anodic Polarization

Operando Surface Optical Reflectance Microscopy Study of Corrosion Film Growth on a Ni–Cr–Mo Alloy During Anodic Polarization

Analysing Sources of Error in Total Internal Reflection Microscopy (TIRM) Experiments and Data Analysis.

Many phenomena observed in synthetic and biological colloidal suspensions are dominated by the static interaction energies and the hydrodynamic interactions that act both between individual particles and also between colloids and macroscopic interfaces. This calls for methods that allow precise measurements of the corresponding forces. One method used for this purpose is total internal reflection microscopy (TIRM), which has been employed for around three decades to measure in particular the interactions between a single particle suspended in a liquid and a solid surface. However, given the importance of the observable variables, it is crucial to understand the possibilities and limitations of the method. In this paper, we investigate the influence of technically unavoidable noise effects and an inappropriate choice of particle size and sampling time on TIRM measurement results. Our main focus is on the measurement of diffusion coefficients and drift velocities, as the influence of error sources on dynamic properties has not been investigated so far. We find that detector shot noise and prolonged sampling times may cause erroneous results in the steep parts of the interaction potential where forces of the order of pico-Newtons or larger act on the particle, while the effect of background noise is negligible below certain thresholds. Furthermore, noise does not significantly affect dynamic data but we find that lengthy sampling times and/or probe particles with too small a radius will cause issues. Most importantly, we observe that dynamic results are very likely to differ from the standard hydrodynamic predictions for stick boundary conditions due to partial slip.

Multiplexed and Millimeter-Scale Fluorescence Nanoscopy of Cells and Tissue Sections via Prism-Illumination and Microfluidics-Enhanced DNA-PAINT.

Fluorescence nanoscopy has become increasingly powerful for biomedical research, but it has historically afforded a small field-of-view (FOV) of around 50 μm × 50 μm at once and more recently up to ∼200 μm × 200 μm. Efforts to further increase the FOV in fluorescence nanoscopy have thus far relied on the use of fabricated waveguide substrates, adding cost and sample constraints to the applications. Here we report PRism-Illumination and Microfluidics-Enhanced DNA-PAINT (PRIME-PAINT) for multiplexed fluorescence nanoscopy across millimeter-scale FOVs. Built upon the well-established prism-type total internal reflection microscopy, PRIME-PAINT achieves robust single-molecule localization with up to ∼520 μm × 520 μm single FOVs and 25-40 nm lateral resolutions. Through stitching, nanoscopic imaging over mm2 sample areas can be completed in as little as 40 min per target. An on-stage microfluidics chamber facilitates probe exchange for multiplexing and enhances image quality, particularly for formalin-fixed paraffin-embedded (FFPE) tissue sections. We demonstrate the utility of PRIME-PAINT by analyzing ∼106 caveolae structures in ∼1,000 cells and imaging entire pancreatic cancer lesions from patient tissue biopsies. By imaging from nanometers to millimeters with multiplexity and broad sample compatibility, PRIME-PAINT will be useful for building multiscale, Google-Earth-like views of biological systems.

Intelligent polyester fabric with fire safety for personal temperature management

The stability of personal thermal management are increasingly indispensable in modern society due to the growing demand for energy savings and environmental protection. Herein, inspired by solid–liquid host–guest materials, we propose a coating preparation strategy that uses a solid flame-retardant gel as the host skeleton filled by a solid–liquid switchable phase change flame-retardant functional guest, thus fabricating smart polyester fabrics for personal temperature management in one step. Both attenuated total reflectance (ATR) and scanning electron microscopy (SEM) are used to confirm the host–guest structure coating on the surface of polyester fabric. Results from simulated cold and heating environments show that the coated polyester fabric has a desirable personal temperature regulation ability. The skin wrapped by the coated polyester fabric presents a higher temperature compared with bare polyester fabric, in simulated cold conditions. Meanwhile, in heating conditions, the internal temperature of the coated polyester fabric is 5.2 oC lower than that of the bare polyester fabric. Furthermore, the coated polyester fabric exhibits excellent flame retardancy in the combustion test, with a horizontal burning rate of 85.7 mm/min and a peak of heat release rate (PHRR) reduction of 52.8 %, attributed to higher graphitization degree and suppressed pyrolysis products. For promoting the practical application, the water vapor transmission, washing resistance, and mechanical performance are also deeply studied. Hence, a phase-change flame-retardant polyester fabric constructed with a host–guest structure provides huge application potentials in various personal temperature management fields, such as snow rescue, field camping, and adventure activities.

Synthesis and characterization of Pt/CuBi2O4. Application to photocatalytic H2 evolution under visible light

The platinized spinel Pt/CuBi2O4 (Pt/CBO) is successfully employed as catalyst for the H2 formation under visible irradiation for the first time. CBO is synthetized by sol gel route from nitrates precursors and calcined at 800 °C. The X-Ray Diffractometry (XRD), X-Ray photoelectron spectroscopy (XPS), UV–Visible diffuse reflectance, Raman spectroscopy and Scanning Electron Microscopy (SEM/EDX) were used for the physical characterization. CBO crystallizes in a tetragonal symmetry (Space Group: P4/ncc). The spinel is p-type semiconductor with a narrow optical gap (1.51 eV) with a transition directly permitted. The reduction of adsorbed H2O molecules to gaseous H2 at ∼ -0.5 VAg/Agcl is evidenced by cyclic voltammetry. The latter is determined from the capacitance measurement in KOH (0.1 M) solution where the spinel exhibits a chemical stability with an exchange current of 50 µA cm−2. The conduction band deriving from the Bi3+: 6p, (3.59 eV/Vacuum / −1.15 VAg/Agcl) is energetically localized above the H2O level (∼-0.7 VAg/Agcl), leading to the feasibility of CBO for the H2 release. The photo-electrochemical activity shows an optimal H2 formation of 270 µmol with a release rate of 8.1 µmol h−1 (mg catalyst)−1 under visible illumination (LED lamp: 3 × 13 W, 1.65 × 1019 photons s−1) in KOH electrolyte (0.1 M) using I− as reducing agent. Pt-islands deposited under UV light improves significantly the photocatalysis (61 %) due to its low overvoltage (∼70 mV) with a quantum yield of 0.91 %, compared to CBO alone.

Unravelling the Mystery inside Cells by Using Single-Molecule Fluorescence Imaging.

Live-cell imaging is a powerful technique to study the dynamics and mechanics of various biological molecules like proteins, organelles, DNA, and RNA. With the rapid evolution of optical microscopy, our understanding of how these molecules are implicated in the cells' most critical physiological roles deepens. In this review, we focus on how spatiotemporal nanoscale live-cell imaging at the single molecule level allows for profound contributions towards new discoveries in life science. This review will start by summarizing how single-molecule tracking has been used to analyze membrane dynamics, receptor-ligand interactions, protein-protein interactions, inner- and extra-cellular transport, gene expression/transcription, and whole organelle tracking. We then move on to how current authors are trying to improve single-molecule tracking and overcome current limitations by offering new ways of labeling proteins of interest, multi-channel/color detection, improvements in time-lapse imaging, and new methods and programs to analyze the colocalization and movement of targets. We later discuss how single-molecule tracking can be a beneficial tool used for medical diagnosis. Finally, we wrap up with the limitations and future perspectives of single-molecule tracking and total internal reflection microscopy.

Effective investigation of murine femoral bone development utilizing correlative light and electron microscopy (CLEM)

BackgroundFor effective investigation of the developing structure and chemistry of bone, comprehensive studies including compositional analysis can be achieved through the gradual observation from the micro- to nanometer scale via correlative light and electron microscopy (CLEM). This technique is particularly useful considering the complex hierarchical arrangement of bioapatite and collagen fibrils which may vary according to specific bone tissue types (i.e., lamellar bone and woven bone) and different growth stages. Scanning electron microscopy (SEM) accompanied with the attachment of the scanning transmission electron microscopy (STEM) detector, referred to as the STEM-in-SEM can be utilized to produce high contrast images from materials composed of light elements, and efficiently allows the selection of suitable accelerating voltage for energy-dispersive spectroscopy (EDS). This study aims to emphasize the efficacy of CLEM techniques through applying STEM-in-SEM and EDS analyses, and its application to comparative murine bone investigation in differing ontogenetic stages.FindingsWe have designed a new grid-holder which can be used for both light and electron microscopy, and we presented an imaging technique for TEM specimens via reflective light microscopy (RLM). For performing CLEM, ultra-thin-sections (UTS) prepared from the femoral bones of 1- to 16-week old of Sprague-Dawley (SD) rats provided light and electron micrographs that can be correlated based on the regions of interest (ROIs). STEM-in-SEM micrographs revealed information not attainable by secondary electron (SE) and back-scattered electron (BSE) micrographs. In addition, for analyzing chemical variation according to growth and development of femoral bones from 1- to 16-week-old rats, comparative chemical analysis was performed through STEM-in-SEM EDS with two reference materials.ConclusionHerein, from femoral bones of SD rats, we have confirmed the rapid chemical and structural variations within the first 8 weeks after birth. STEM-in-SEM micrographs revealed the bone development process of the early stage porous bone matrix subsequently being filled with collagen fibrils and bioapatite. In addition, chemical analysis for carbon and oxygen showed the ratios of inorganic to organic phases according to growth and progress in bone mineralization. As a result, we were able to postulate the growth mechanism of murine femoral bone in the neonatal stages of development. We also anticipate that our CLEM techniques can be further utilized for more thorough investigation of bone structure and chemistry in diverse scales.

Epitaxial growth of oriented CoO films by radio-frequency sputtering deposition

Rock-salt CoO is a p-type semiconductor and its Néel temperature is close to room temperature. CoO-based compounds are known as promising systems for renewable energy harvest with high efficiency. CoO with catalytic and exchange bias properties can be widely used for industrial applications. In this paper, we report high-quality stable CoO(111) and (100) films epitaxially grown on c-cut (0001) and r-cut (101‾2) α-Al2O3 substrates, respectively, using radio-frequency sputtering deposition. X-ray diffraction (XRD) measurements revealed that the CoO films had a rock-salt structure (Fm3m) with lattice constants of 4.2477 Å and 4.2617 Å for film grown on (0001) and (101‾2) α-Al2O3 substrates, respectively. CoO films with the best crystal quality were grown at a substrate temperature of ∼700 °C. XRD measurements of CoO(111) films indicated a lack of structural residual strain, whereas CoO(100) films had substantial amounts of structural strain. X-ray reflectivity (XRR) and transmission electron microscopy measurements showed neither oxygen vacancy nor defects in both CoO(111) and (100) films. XRR revealed that the mean electron density of the CoO films was nearly identical to a pure CoO and that the films were considerably stable under the atmosphere.

Hypomyelination, hypodontia and craniofacial abnormalities in a Polr3b mouse model of leukodystrophy.

RNA polymerase III (Pol III)-related hypomyelinating leukodystrophy (POLR3-HLD), also known as 4H leukodystrophy, is a severe neurodegenerative disease characterized by the cardinal features of hypomyelination, hypodontia and hypogonadotropic hypogonadism. POLR3-HLD is caused by biallelic pathogenic variants in genes encoding Pol III subunits. While approximately half of all patients carry mutations in POLR3B encoding the RNA polymerase III subunit B, there is no in vivo model of leukodystrophy based on mutation of this Pol III subunit. Here, we determined the impact of POLR3BΔ10 (Δ10) on Pol III in human cells and developed and characterized an inducible/conditional mouse model of leukodystrophy using the orthologous Δ10 mutation in mice. The molecular mechanism of Pol III dysfunction was determined in human cells by affinity purification-mass spectrometry and western blot. Postnatal induction with tamoxifen induced expression of the orthologous Δ10 hypomorph in triple transgenic Pdgfrα-Cre/ERT; R26-Stopfl-EYFP; Polr3bfl mice. CNS and non-CNS features were characterized using a variety of techniques including microCT, ex vivo MRI, immunofluorescence, immunohistochemistry, spectral confocal reflectance microscopy and western blot. Lineage tracing and time series analysis of oligodendrocyte subpopulation dynamics based on co-labelling with lineage-specific and/or proliferation markers were performed. Proteomics suggested that Δ10 causes a Pol III assembly defect, while western blots demonstrated reduced POLR3BΔ10 expression in the cytoplasm and nucleus in human cells. In mice, postnatal Pdgfrα-dependent expression of the orthologous murine mutant protein resulted in recessive phenotypes including severe hypomyelination leading to ataxia, tremor, seizures and limited survival, as well as hypodontia and craniofacial abnormalities. Hypomyelination was confirmed and characterized using classic methods to quantify myelin components such as myelin basic protein and lipids, results which agreed with those produced using modern methods to quantify myelin based on the physical properties of myelin membranes. Lineage tracing uncovered the underlying mechanism for the hypomyelinating phenotype: defective oligodendrocyte precursor proliferation and differentiation resulted in a failure to produce an adequate number of mature oligodendrocytes during postnatal myelinogenesis. In summary, we characterized the Polr3bΔ10 mutation and developed an animal model that recapitulates features of POLR3-HLD caused by POLR3B mutations, shedding light on disease pathogenesis, and opening the door to the development of therapeutic interventions.

Does dinocyst wall composition really reflect trophic affinity? New evidence from ATR micro-FTIR spectroscopy measurements.

Attenuated total reflection (ATR) microscope Fourier transform infrared (micro-FTIR) spectroscopy was used to investigate the dinosporin composition in the walls of modern, organic-walled dinoflagellate resting cysts (dinocysts). Variable cyst wall compositions were observed, which led to the erection of four spectrochemical groups, some with striking similarities to other resistant biomacromolecules such as sporopollenin and algaenan. Furthermore, possible proxies derivable from the spectrochemical composition of modern and fossil dinocysts were discussed. The color of the dinocyst walls was reflected in the spectral data. When comparing that color with a standard and the results of a series of bleaching experiments with oxidative agents, eumelanin was assigned as a likely pigment contributing to the observed color. Following this assignment, the role of eumelanin as an ultraviolet sunscreen in colored dinocysts was hypothesized, and its implications on the autofluorescence and morphological preservation of dinocysts were further discussed. Unlike what had previously been assumed, it was shown that micro-FTIR data from dinocysts cannot be used to unambiguously infer trophic affinities of their associated cells. Finally, using methods with high spatial resolutions (synchrotron transmission micro-FTIR and optical photothermal infrared spectroscopy), it was shown that dinocyst wall layers are chemically homogenous at the probed scales. This study fills a large knowledge gap in our understanding of the chemical nature of dinocyst walls and has nuanced certain assumptions and interpretations made in the past.

Accelerated in vitro oxidative degradation testing of polypropylene surgical mesh.

Polypropylene (PP) surgical mesh had reasonable success in repair of hernia and treatment of stress urinary incontinence (SUI); however, their use for the repair of pelvic organ prolapse (POP) resulted in highly variable results with lifelong complications in some patients. One of several factors that could be associated with mesh-related POP complications is changes in the properties of the implanted surgical mesh due to oxidative degradation of PP in vivo. Currently, there are no standardized in vitro bench testing methods available for assessing the susceptibility to oxidative degradation and estimating long-term in vivo stability of surgical mesh. In this work, we adapted a previously reported automated reactive accelerated aging (aRAA) system, which uses elevated temperatures and high concentrations of hydrogen peroxide (H2 O2 ), for accelerated bench-top oxidative degradation testing of PP surgical mesh. Since H2 O2 is highly unstable at elevated temperatures and for prolonged periods, the aRAA system involves a feedback loop based on electrochemical detection methods to maintain consistent H2 O2 concentration in test solutions. Four PP mesh samples with varying mesh knit designs, filament diameter, weight, and % porosity, were selected for testing using aRAA up to 4 weeks and characterized using thermal analysis, Fourier-transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) and scanning electron microscopy (SEM). Additionally, the oxidation index (OI) values were calculated based on the FTIR-ATR spectra to estimate the oxidative degradation and oxidation reaction kinetics of PP surgical mesh. The OI values and surface damage in the form of surface flaking, peeling, and formation of transverse cracks increased with aRAA aging time. The aRAA test method introduced here could be used to standardize the assessment of long-term stability of surgical mesh and may also be adopted for accelerated oxidative degradation testing of other polymer-based medical devices.

Furnaces, hearths, rituals, and construction: investigating the utilisation of woody plant species at the Early Iron Age site of Ndondondwane by means of identifying archaeological charcoal

Ndondondwane, an Early Iron Age settlement situated on the banks of the Thukela River, KwaZulu-Natal, South Africa, provides a unique record of a single, short-term occupation (c. 1300 to 1200 years ago). Several areas associated with different activities had been previously excavated and analysed, yielding various scenarios for the cultural and social organisation of the settlement. Three phases of occupation or cultural horizons have been identified and this paper largely explores the charcoal assemblage from the middle cultural horizon, during the settlement’s maximum extent of occupation. Charcoal was analysed from the central part of the site, represented by a livestock byre (kraal), a meeting place, and a craft production area; as well as the peripheral areas including three domestic middens and a charcoal preparation area. Archaeological charcoal specimens were examined using reflective light microscopy to observe the characteristic anatomical features needed to determine the taxonomic group they represent and subsequently identified by direct comparison with a modern charcoal reference collection and published archaeological charcoal studies. Charcoal was identified as belonging to 15 families, 23 genera, and 29 species of trees with known fuel, construction, and medicinal uses. There was a preference for wood previously known as Acacia*, indicating that this genus was readily available and prolific in the surrounds of the site. Ndondondwane has been extensively investigated in terms of the archaeology, and this together with the anthracology data provides further insight into Early Iron Age settlement location-specific activities, cultural practices, and reasons for abandonment.

Interrogating the Light-Induced Charging Mechanism in Li-Ion Batteries Using Operando Optical Microscopy.

Photobatteries, batteries with a light-sensitive electrode, have recently been proposed as a way of simultaneously capturing and storing solar energy in a single device. Despite reports of photocharging with multiple different electrode materials, the overall mechanism of operation remains poorly understood. Here, we use operando optical reflection microscopy to investigate light-induced charging in LixV2O5 electrodes. We image the electrode, at the single-particle level, under three conditions: (a) with a closed circuit and light but no electronic power source (photocharging), (b) during galvanostatic cycling with light (photoenhanced), and (c) with heat but no light (thermal). We demonstrate that light can indeed drive lithiation changes in LixV2O5 while maintaining charge neutrality, possibly via a combination of faradaic and nonfaradaic effects taking place in individual particles. Our results provide an addition to the photobattery mechanistic model highlighting that both intercalation-based charging and lithium concentration polarization effects contribute to the increased photocharging capacity.

Strong Dipolar Repulsion of One-Dimensional Interfacial Excitons in Monolayer Lateral Heterojunctions.

Repulsive and long-range exciton-exciton interactions are crucial for the exploration of one-dimensional (1D) correlated quantum phases in the solid state. However, the experimental realization of nanoscale confinement of a 1D dipolar exciton has thus far been limited. Here, we demonstrate atomically precise lateral heterojunctions based at transitional-metal dichalcogenides (TMDCs) as a platform for 1D dipolar excitons. The dynamics and transport of the interfacial charge transfer excitons in a type II WSe2-WS1.16Se0.84 lateral heterostructure were spatially and temporally imaged using ultrafast transient reflection microscopy. The expansion of the exciton cloud driven by dipolar repulsion was found to be strongly density dependent and highly anisotropic. The interaction strength between the 1D excitons was determined to be ∼3.9 × 10-14 eV cm-2, corresponding to a dipolar length of 310 nm, which is a factor of 2-3 larger than the interlayer excitons at two-dimensional van der Waals vertical interfaces. These results suggest 1D dipolar excitons with large static in-plane dipole moments in lateral TMDC heterojunctions as an exciting system for investigating quantum many-body physics.

Modeling periodontal host-microbe interactions using vascularized gingival connective tissue equivalents

Gingival connective tissue and its vasculature play a crucial role in the host’s immune response against the periodontal microbiome and serve as a bridge between the oral and systemic environments. However, there is a lack of representative models that mimic the complex features of vascularized gingival connective tissue and its interaction with the periodontal microbiome, hindering our understanding of periodontal health and disease. Towards this pursuit, we present the characterization of vascularized gingival connective tissue equivalents (CTEs) as a model to study the interactions between oral biofilm colonizers and gingival tissues in healthy and diseased states. Whole-mount immunolabeling and label-free confocal reflectance microscopy of human fibrin-based matrix embedded with gingival fibroblasts and microvascular endothelial cells demonstrated the generation of bi-cellular vascularized gingival CTEs. Next, we investigated the response of the vascularized gingival CTEs to early, intermediate, and late oral biofilm colonizers. Despite colonization, the early colonizers did not elicit any significant change in the production of the cytokines and chemokines by the CTEs representative of the commensal and homeostatic state. In contrast, intermediate and late colonizers representing a transition to a diseased state exhibited connective tissue and vascular invasion, and elicited a differential immune response accompanied by increased monocyte migration. The culture supernatants produced by the vascularized gingival CTEs in response to early and intermediate colonizers polarized macrophages towards an immunomodulatory M2-like phenotype which activates and protects the host, while the late colonizers polarized towards a pro-inflammatory M1-like phenotype. Lastly, in silico analysis showed a high strength of associations between the proteins and transcripts investigated with periodontitis and vascular diseases. In conclusion, the vascularized gingival CTEs provide a biomimetic in vitro platform to study host-microbiome interactions and innate immune response in periodontal health and diseased states, which potentially paves the way toward the development and assessment of novel periodontal therapeutics.

Formation of structured silica layers from Dodecaphenyl POSS thin films via microwave-induced oxygen plasma treatment

The study investigated the effect of microwave-induced oxygen plasma on Dodecaphenyl-POSS (Ph12T12) thin films that were obtained by Physical Vapor Deposition (PVD) in an Ultra-High Vacuum (UHV) system. Due to its ability to self-assemble and its relatively low cost, Ph12T12 is a promising material as a precursor for the fabrication of silica thin films. The study found that the treatment of the Ph12T12 thin film with oxygen plasma results in the formation of a new material with a cage-like structure preserved. The thin films were examined using X-ray Reflectivity (XRR), Raman spectroscopy, and Atomic Force Microscopy (AFM). The results showed significant changes in the microstructure, chemical composition, and topography of the annealed POSS films. Thermal and plasma treatment improved the thermal resistance of the surface layer, increasing the evaporation temperature by over 80 °C. XRR modeling of the films' spectra enabled the determination of the composition of each interphase. Additionally, Bragg reflections (00l) remained visible on the spectra after annealing, indicating the presence of a preserved POSS cage-like structure.

Optical Orientation Mapping of Additively Manufactured Alloys Using Directional Reflectance Microscopy.

Optical Orientation Mapping of Additively Manufactured Alloys Using Directional Reflectance Microscopy.

Unveiling the Rational Development of Stimuli-Responsive Silk Fibroin-Based Ionogel Formulations.

We present an approach for the rational development of stimuli-responsive ionogels which can be formulated for precise control of multiple unique ionogel features and fill niche pharmaceutical applications. Ionogels are captivating materials, exhibiting self-healing characteristics, tunable mechanical and structural properties, high thermal stability, and electroconductivity. However, the majority of ionogels developed require complex chemistry, exhibit high viscosity, poor biocompatibility, and low biodegradability. In our work, we overcome these limitations. We employ a facile production process and strategically integrate silk fibroin, the biocompatible ionic liquids (ILs) choline acetate ([Cho][OAc]), choline dihydrogen phosphate ([Cho][DHP]), and choline chloride ([Cho][Cl]), traditional pharmaceutical excipients, and the model antiepileptic drug phenobarbital. In the absence of ILs, we failed to observe gel formation; yet in the presence of ILs, thermoresponsive ionogels formed. Systems were assessed via visual tests, transmission electron microscopy, confocal reflection microscopy, dynamic light scattering, zeta potential and rheology measurements. We formed diverse ionogels of strengths ranging between 18 and 642 Pa. Under 25 °C storage, formulations containing polyvinylpyrrolidone (PVP) showed an ionogel formation period ranging over 14 days, increasing in the order of [Cho][DHP], [Cho][OAc], and [Cho][Cl]. Formulations lacking PVP showed an ionogel formation period ranging over 32 days, increasing in the order of [Cho][OAc], [Cho][DHP] and [Cho][Cl]. By heating from 25 to 60 °C, immediately following preparation, thermoresponsive ionogels formed below 41 °C in the absence of PVP. Based on our experimental results and density functional theory calculations, we attribute ionogel formation to macromolecular crowding and confinement effects, further enhanced upon PVP inclusion. Holistically, applying our rational development strategy enables the production of ionogels of tunable physicochemical and rheological properties, enhanced drug solubility, and structural and energetic stability. We believe our rational development approach will advance the design of biomaterials and smart platforms for diverse drug delivery applications.