Additive manufacturing has revolutionized the fabrication of complex 3D materials. Hydrogels are commonly used as "inks" in 3D printing and offer easy mixing and processing of many materials. Here, the synthesis and characterization of a new library of thermoresponsive ABC triblock copolymers based on oligo(ethylene glycol) methyl ether methacrylate (OEGMA, Molar Mass, MM = 300 g mol-1, A block), 2-phenylethyl methacrylate (PhEMA, B block) and di(ethylene glycol) methyl ether methacrylate (DEGMA, C block) is reported. Polymers of different comonomer compositions were fabricated and investigated in terms of their aqueous solution properties and their ability to form thermogels. The most promising polymer was then used to fabricate a graphene-containing ink, and graphene constructs were successfully printed and characterized in terms of the electrical conductivity properties.

ABSTRACTPolyolefin degradation is widely studied to assess the lifetime of packaging materials. In this work, a combination of bulk (DSC, GPC, 13C‐NMR, XRD), surface (FTIR) and cross‐sectional characterization (Raman spectroscopy and nanoindentation) was used to examine changes in the mechanical properties and microstructure of two different commercially‐available polyolefins, with similar crystallinities, produced by injection molding—a polypropylene homopolymer (PPH) and a polypropylene random copolymer (PPRC)—aged under accelerated UV‐A conditions. The aim was to characterize the variations in the crystallinity and microstructure across the cross‐section of these materials. Our results suggest that the presence of ethylene comonomer units in PPRC results, on average, in smaller crystal dimensions, leads to improved packing, and a more homogeneous microstructure and hardness across the cross‐section of the sample. The ethylene monomers stabilize PPRC from oxidation during the first 14 days of accelerated aging, but eventually the rate of degradation matches the PPH at 28 days of aging, probably because of the higher surface area to volume ratio of the smaller crystals. The work emphasizes the importance of incorporating ethylene comonomers into polyolefins to limit variation of the microstructure across the core to the skin layer, for improved future design of packaging that degrades fully.

Growth plate cartilage (GP) serves as a dynamic site of active mineralization and offers a unique opportunity to investigate the cell-regulated matrix mineralization process. Transmission electron microscopy (TEM) provides a means for the direct observation of these mechanisms, offering the necessary resolution and chemical analysis capabilities. However, as mineral crystallinity is prone to artifacts using aqueous fixation protocols, sample preparation techniques are critical to preserve the mineralized tissue in its native form. We optimized cryofixation by high-pressure freezing followed by freeze substitution in anhydrous acetone containing 0.5 % uranyl acetate to prepare murine GP for TEM analysis. This sample preparation workflow maintains cellular and extracellular protein structural integrity with sufficient contrast for observation and without compromising mineral crystallinity. By employing appropriate sample preparation techniques, we were able to observe two parallel mineralization processes driven by chondrocytes: 1) intracellular- and 2) extracellular-originating mineralized vesicles. Both mechanisms are based on sequestering calcium phosphate (CaP) within a membrane-limited structure, albeit originating from different compartments of the chondrocytes. In the intracellular originating pathway, CaP accumulates within mitochondria as globular CaP granules, which are incorporated into intracellular vesicles (500-1000 nm) and transported as granules to the extracellular matrix (ECM). In contrast, membrane budding vesicles with a size of approximately 100-200 nm, filled with needle-shaped minerals were observed only in the ECM. Both processes transport CaP to the collagenous matrix via vesicles, they can be differentiated based on the vesicle size and mineral morphologies. Their individual importance to the cartilage mineralization process is yet to be determined. STATEMENT OF SIGNIFICANCE: We do not fully understand the process by which epiphyseal cartilage mineralizes - a vital step in endochondral bone formation. Previous work has proposed that mitochondria and intracellular vesicles are storage sites for the delivery of mineral to collagen fibrils. However, these concepts are founded on results from in vitro models of mineralization; no prior work has observed mineral-containing intracellular vesicles or mitochondria in developing epiphyseal cartilage. Here we developed a new cryofixation preparation route for transmission electron microscopy (TEM) imaging that has disclosed a cell-regulated process of mineralization in epiphyseal cartilage. High resolution TEM images revealed an involvement of mitochondria and intracellular and extracellular vesicles in delivering transient mineral phases to the collagen fibrils to promote cartilage mineralization.

Glioblastoma (GBM) is an extremely infiltrative brain cancer that is impossible to fully remove surgically and almost always recurs at the borders of the resection cavity. There is increasing focus on inducing cancer cell death using magneto-mechanical therapy (MMT), which involves energy conversion of an external low-frequency magnetic field into mechanical forces using magnetic nanoparticles. Here, we combined MMT with enhanced radiotherapy (RT)─the standard of care treatment for GBM─to increase the efficiency of treatment using gold-iron nanowires (AuFe NWs). The magnetic iron component of the nanowires mechanically rotates, inducing cellular damage, and the gold scatters X-rays due to its high atomic number, enhancing the local RT dose. We show that reproducible synthesis of AuFe NWs with different ratios of gold:iron can be achieved using a hard-template electrochemical method, controlling composition by tuning the deposition current. Ratios with best-performing iron percentages were selected for computational modeling to predict which frequency should be applied in vitro on a GBM cell line. In vitro testing, using a cell metabolism assay, and the optimal frequency and gold:iron ratio, demonstrated that applying MMT alongside RT resulted in a synergistic effect, reducing cell viability significantly by ∼60% (as compared with a 30% reduction for RT, with/without AuFe NWs), and a 20% reduction for MMT (with AuFe NWs). The increased efficacy of RT, post-MMT, was attributed to the higher association of the nanowires with the cells following application of the magnetic field and local membrane damage.

Mango seed kernel extract (MSKE) and its phytochemical compositions were investigated for their anticancer activities and synergistic effects with doxorubicin (DOX) against hepatocellular carcinoma (HCC) in both 2D and 3D culture models. Molecular docking studies were conducted to elucidate the mechanisms of DOX, MSKE, and major phytochemical components against overexpressed HCC-related proteins. Co-delivery of DOX and MSKE demonstrated significant synergistic anticancer activity in both models. A sequential nanotheranostic platform (SNP), consisting of MSKE encapsulated aminated hollow mesoporous silica nanoparticles capped with graphene quantum dots (GQD-MSKE-NH2HMSNs) and DOX encapsulated HMSNs (DOX-HMSNs), was synthesized for HCC treatment. GQD conjugation allowed real-time cellular tracking and photothermal therapy (PTT). The SNP exhibited particle sizes of 96.12 ± 5.12 nm for GQD-MSKE-NH2HMSNs and 94.99 ± 6.30 nm for DOX-HMSNs, both with positive surface charges. Encapsulation efficiency (%EE) and loading capacity (%LC) of GQD-MSKE-NH2HMSNs were 95.50 ± 0.20% and 46.72 ± 1.14%, respectively, while DOX-HMSNs achieved 96.42 ± 2.48 %EE and 29.0 ± 0.70 %LC. GQD-MSKE-NH2HMSNs provided PTT and disrupted the tumor microenvironment, collagen type 1, thereby enhancing the penetration of GQD-MSKE-NH2HMSNs in 3D-HCC spheroids. In parallel, DOX-HMSNs exhibited a pH-responsive drug release behavior, allowing controlled DOX delivery in the acidic tumor area. Therefore, the SNP demonstrated significantly higher anticancer efficacy than the combination of MSKE and DOX at equivalent concentrations and provided the synergistic effect of the triple combination therapy (herbal adjuvant, PTT and chemotherapy) against HCC.

Bone structure is generally hierarchically organized into organic (collagen, proteins, ...), inorganic (hydroxyapatite (HAP)) components. However, many fundamental mechanisms of the biomineralization processes such as HAP formation, the influence of trace elements, the mineral-collagen arrangement, etc., are not clearly understood. This is partly due to the analytical challenge of simultaneously characterizing the three-dimensional (3D) structure and chemical composition of biominerals in general at the nanometer scale, which can, in principle be achieved by atom probe tomography (APT). Yet, the hierarchical structures of bone represent a critical hurdle for APT analysis in terms of sample yield and analytical resolution, particularly for trace elements, and organic components from the collagen appear to systematically get lost from the analysis. Here, we applied in-situ metallic coating of APT specimens within the focused ion beam (FIB) used for preparing specimens, and demonstrate that the sample yield and chemical sensitivity are tremendously improved, allowing the analysis of individual collagen fibrils and trace elements such as Mg and Na. We explored a range of measurement parameters with and without coating, in terms of analytical resolution performance and determined the best practice parameters for analyzing bone samples in APT. To decipher the complex mass spectra of the bone specimens, reference spectra from pure HAP and collagen were acquired to unambiguously identify the signals, allowing us to analyze entire collagen fibrils and interfaces at the near-atomic scale. Our results open new possibilities for understanding the hierarchical structure and chemical heterogeneity of bone structures at the near-atomic level and demonstrate the potential of this new method to provide new, unexplored insights into biomineralization processes in the future. STATEMENT OF SIGNIFICANCE: Atom probe tomography (APT) is a relatively new technique for the analysis of bones, teeth or biominerals in general. APT can characterize the microstructure of materials in 3D down to the near-atomic level, combined with a high elemental sensitivity, down to parts per million. APT application to study biomineralization phenomena is plagued by low sample yield and poorer analytical performance compared to metals. Here we have overcome these limitations by in-situ metal coating of APT specimens. This can unlock future APT analysis to gain insights into fundamental biomineralization processes, e.g. collagen/hydroxyapatite interaction, influence of trace elements and a better understanding of bone diseases or bone biomineralization in general.

Peat fires emit large quantities of particles and gases, which cause extensive haze events. This study reports on the physicochemical properties of particles emitted from smouldering peat fires.

Air pollution is a growing global health threat, exacerbated by climate change and linked to cardiovascular and respiratory diseases. While personal sensing devices enable real-time physiological monitoring, their integration with environmental data for individualised health prediction remains underdeveloped. Here, we present a modular, cloud-based framework that predicts personalised physiological responses to pollution by combining wearable-derived data with real-time environmental exposures. At its core is an Adversarial Autoencoder (AAE), initially trained on high-resolution pollution-health data from the INHALE study and fine-tuned using smartwatch data via transfer learning to capture individual-specific patterns. Consistent with changes in pollution levels commonly observed in the real-world, simulated pollution spikes (+100

Osteoporosis affects more than 200 million people worldwide, with an osteoporotic fracture occurring approximately every 3 seconds; with ageing populations, its prevalence continues to rise, yet it remains under-diagnosed and under-treated. Strontium- and calcium-doped mesoporous bioactive glass nanoparticles (BGNPs) are promising due to their ability to combine bioactive bone-regenerative function with controlled therapeutic ion release. We optimized a one-step sol–gel (modified Stöber) synthesis by varying the solvent system (pure water vs. 1:1 ethanol/water) to control BGNP size and morphology and assessed their effects on pre-osteoblasts (MC3T3-E1). Characterization by electron microscopy, X-ray photoelectron spectroscopy, and ^29Si MAS NMR showed that ethanol inclusion yielded smaller, uniform spherical particles (74 ± 5 nm), whereas water alone produced significantly larger particles (224 ± 42 nm). Both Sr2+ and Ca2+ were incorporated as network modifiers within an amorphous silicate framework, with no crystalline phases. Cytocompatibility assays revealed a size-dependent response: larger particles reduced cell viability at 1 μg/mL, while both sizes were biocompatible at 0.1 μg/mL. At the non-toxic concentration of 0.1 μg/mL, BGNPs enhanced alkaline phosphatase activity, promoted osteogenic differentiation, and exhibited antioxidant activity by scavenging tert-butyl hydroperoxide-induced free radicals. These results indicate that solvent-controlled synthesis effectively tunes BGNP size without disrupting silicate network integrity, and that properly sized Sr/Ca-doped BGNPs support both osteogenic and antioxidant responses, making them strong candidates for advanced therapeutic approaches in osteoporosis treatment.

Our knowledge of cells’ internal organelles, comes mostly from EM but here we image them optically, for the first time. Our ~20nm resolution beats diffraction by ~400x, and our mid-IR spectroscopy gives lable-free chemical contrast.

Mesoporous silica nanoparticles (MSNPs) are promising nanomedicine vehicles due to their biocompatibility and ability to carry large cargoes. It is critical in nanomedicine development to be able to map their uptake in cells, including distinguishing surface associated MSNPs from those that are embedded or internalized into cells. Conventional nanoscale imaging techniques, such as electron and fluorescence microscopies, however, generally require the use of stains and labels to image both the biological material and the nanomedicines, which can interfere with the biological processes at play. We demonstrate an alternative imaging technique for investigating the interactions between cells and nanostructures, scattering-type scanning near-field optical microscopy (s-SNOM). s-SNOM combines the chemical sensitivity of infrared spectroscopy with the nanoscale spatial resolving power of scanning probe microscopy. We use the technique to chemically map the uptake of MSNPs in whole human glioblastoma cells and show that the simultaneously acquired topographical information can provide the embedding status of the MSNPs. We focus our imaging efforts on the lamellipodia and filopodia structures at the peripheries of the cells due to their significance in cancer invasiveness.

An ever-present limitation of transmission electron microscopy is the damage caused by high-energy electrons interacting with any sample. By reconsidering the fundamentals of imaging, we demonstrate an event-responsive approach to electron microscopy that delivers more information about the sample for a given beam current. Measuring the time to achieve an electron count threshold rather than waiting a predefined constant time improves the information obtained per electron. The microscope was made to respond to these events by blanking the beam, thus reducing the overall dose required. This approach automatically apportions dose to achieve a given signal-to-noise ratio in each pixel, eliminating excess dose that is associated with diminishing returns of information. We demonstrate the wide applicability of our approach to beam-sensitive materials by imaging biological tissue and zeolite.

Ageing- or bone-related diseases, such as osteoporosis leads to perturbations in the collagenous framework and mineralization that translate to deteriorated fracture resistance at the whole-bone level. However, bulk mechanical testing is insufficient to isolate the effect of these alterations on the mechanical response at a smaller length scale where molecular modifications manifest. Here, we combine in situ micromechanical testing using micropillars to determine elastic moduli, double cantilever beam mechanical tests to measure fracture toughness, and transmission electron microscopy (TEM) relate crack propagation at the microscale to local variations in collagen fibril organization. An osteopontin (OPN) knock out bone model with nanometer scale with regions of organised and disorganised collagen matrix and deteriorated fracture resistance at the whole-bone level was used to explore whether it is possible to propagate a crack in a transversely orientated pillar if the collagen fibrils in the pillar are disorganized. The average measured fracture energy for OPN-deficient mouse bone at this length scale, in the transverse direction was 0.94 ± 0.67 J/m2. This value is significantly lower than wild type bone, which we found in previous studies to be approximately 20 J/m2. TEM of cross-sections of the cracked pillars showed that the lack of OPN caused disorganization of the fibrillar network, possibly leading to deteriorated fracture resistance in bones. These preliminary findings indicate that OPN may contribute to bone’s fracture resistance through collagen matrix organization. This study serves as a starting point for more in-depth investigations that use in situ micromechanical testing using micropillars to study interplay between the ultrastructure and fracture resistance in pathologic bone.

We use infrared nanoscopy to image subcellular components of hippocampal neurons in a chemistry specific way and to study their interaction with therapeutic nanoparticles.

Conditions affecting the brain are the second leading cause of death globally. One of the main challenges for drugs targeting brain diseases is passing the blood-brain barrier (BBB). Here, the effectiveness of mesoporous silica nanostars (MSiNSs) with two different spike lengths to cross an in vitro BBB multicellular model was evaluated and compared to spherical nanoparticles (MSiNP). A modified sol-gel single-micelle epitaxial growth was used to produce MSiNS, which showed no cytotoxicity or immunogenicity at concentrations of up to 1 μg mL-1 in peripheral blood mononuclear and neuronal cells. The nanostar MSiNS effectively penetrated the BBB model after 24 h, and MSiNS-1 with a shorter spike length (9 ± 2 nm) crossed the in vitro BBB model more rapidly than the MSiNS-2 with longer spikes (18 ± 4 nm) or spherical MSiNP at 96 h, which accumulated in the apical and basolateral sides, respectively. Molecular dynamic simulations illustrated an increase in configurational flexibility of the lipid bilayer during contact with the MSiNS, resulting in wrapping, whereas the MSiNP suppressed membrane fluctuations. This work advances an effective brain drug delivery system based on virus-like shaped MSiNS for the treatment of different brain diseases and a mechanism for their interaction with lipid bilayers.

We estimated the particle number distributions (PNDs), particle number concentrations (PNCs), physicochemical characteristics, meteorological effects, and respiratory deposition doses (RDD) in the human respiratory tract for three different particle modes: nucleation (N6–30), accumulation (N30–300), and coarse (N300–10,000) modes. This study was conducted in three different microenvironments (MEs) in London (indoor, IN; traffic intersection, TI; park, PK) measuring particles in the range of 6 nm–10,000 nm using an electrical low-pressure impactor (ELPI+). Mean PNCs were 1.68 ± 1.03 × 104 #cm−3, 7.00 ± 18.96 × 104 #cm−3, and 0.76 ± 0.95 × 104 #cm−3 at IN, TI, and PK, respectively. The PNDs were high for nucleation-mode particles at the TI site, especially during peak traffic hours. Wind speeds ranging from 0 to 6 ms−1 exhibit higher PNCs for nucleation- and accumulation-mode particles at TI and PK sites. Physicochemical characterisation shows trace metals, including Fe, O, and inorganic elements, that were embedded in a matrix of organic material in some samples. Alveolar RDD was higher for the nucleation and accumulation modes than the coarse-mode particles. The chemical signatures from the physicochemical characterisation indicate the varied sources at different MEs. These findings enhance our understanding of the different particle profiles at each ME and should help devise ways of reducing personal exposure at each ME.

The ability to image cell chemistry at the nanoscale is key for understanding cell biology, but many optical microscopies are restricted by the ~(200–250)nm diffraction limit. Electron microscopy and super-resolution fluorescence techniques beat this limit, but rely on staining and specialised labelling to generate image contrast. It is challenging, therefore, to obtain information about the functional chemistry of intracellular components. Here we demonstrate a technique for intracellular label-free chemical mapping with nanoscale (~30 nm) resolution. We use a probe-based optical microscope illuminated with a mid-infrared laser whose wavelengths excite vibrational modes of functional groups occurring within biological molecules. As a demonstration, we chemically map intracellular structures in human multiple myeloma cells and compare the morphologies with electron micrographs of the same cell line. We also demonstrate label-free mapping at wavelengths chosen to target the chemical signatures of proteins and nucleic acids, in a way that can be used to identify biochemical markers in the study of disease and pharmacology.

We compared various pollutant concentrations (PM1, PM2.5, PM10, PNC, BC) at four different urban microen-vironments (MEs) in London (Indoor, IN; Traffic Intersection, TI; Park, PK; and Street Canyon, SC). The physico-chemical characteristics of particles were analysed, and the respiratory deposition doses (RDD) were estimated. Field measurements were conducted over a period of 121 days. The mean PM2.5 (PNC) concentrations were found to be 9.47 +/- 7.05 (16366 +/- 11815), 8.09 +/- 4.57 (10951 +/- 6445), 5.11 +/- 2.96 (7717 +/- 4576), 3.88 +/- 3.06 (5672 +/- 2934) mu g m3 (# cm-3) at TI, SC, PK and IN, respectively. PM2.5, PM10 and PNC exhibited a trend of TI > SC > PK > IN; higher concentrations for PM1 and BC were observed at IN than PK due to the emissions from printers, producing a trend of TI > SC > IN > PK. We observed 12%-30% higher fine PM concentrations at TI and SC sites during morning peak (07:00-09:30) than the evening peak hours (16:00-19:00); while IN showed a smaller variation in fine PM concentrations compared with outdoor TI, PK and SC sites owing to their prevalence in the IN for a longer time. Fine and ultrafine PM containing potentially toxic trace transition metals including Fe, Ti, Cr, Mn, Al and Mg were detected by high resolution electron microscopy at all sites. There was a similar relative abundance of different elements at the TI, IN and PK sites, which suggests a transport of PM between MEs. RDD for PM1 was highest (2.45 +/- 2.27 mu g h-1) at TI for females during running; PM2.5 and PM10 were highest at SC (11.23 +/- 6.34 and 37.17 +/- 20.82 mu g h-1, respectively). The results show that the RDD variation between MEs does not follow the PM concentration trend. RDD at PK was found to be 39%-53% lower than TI and SC during running for all the PM fractions. Overall, the study findings show the air quality variation at different MEs and reveals the exposure inequalities around the city, which enable the management of personal exposure by selecting appropriate MEs for different activities.

Magnetic-stimuli responsive hydrogels are quickly becoming a promising class of materials across numerous fields, including biomedical devices, soft robotic actuators, and wearable electronics. Hydrogels are commonly fabricated by conventional methods that limit the potential for complex architectures normally required for rapidly changing custom configurations. Rapid prototyping using 3D printing provides a solution for this. Previous work has shown successful extrusion 3D printing of magnetic hydrogels; however, extrusion-based printing is limited by nozzle resolution and ink viscosity. VAT photopolymerization offers a higher control over resolution and build-architecture. Liquid photo-resins with magnetic nanocomposites normally suffer from nanoparticle agglomeration due to local magnetic fields. In this work, we develop an optimised method for homogenously infusing up to 2 wt % superparamagnetic iron oxide nanoparticles (SPIONs) with a 10 nm diameter into a photo-resin composed of water, acrylamide and PEGDA, with improved nanoparticle homogeneity and reduced agglomeration during printing. The 3D printed starfish hydrogels exhibited high mechanical stability and robust mechanical properties with a maximum Youngs modulus of 1.8 MPa and limited shape deformation of 10% when swollen. Each individual arm of the starfish could be magnetically actuated when a remote magnetic field is applied. The starfish could grab onto a magnet with all arms when a central magnetic field was applied. Ultimately, these hydrogels retained their shape post-printing and returned to their original formation once the magnetic field had been removed. These hydrogels can be used across a wide range of applications, including soft robotics and magnetically stimulated actuators.