Journals
2025 EN
Kedzierski Alexander · Kheirabadi Sina · Jaberi Arian
+7 more
Abstract Granular hydrogel scaffolds (GHS), composed of jammed hydrogel microparticles (microgels), have emerged to overcome the structural limitations of nonporous (bulk) hydrogels. Microscale void spaces among jammed microgels in GHS promote cell infiltration and host tissue integration; however, the prevalent use of spherical nonporous microgels limits the GHS void fraction to that of random close packing. To address this persistent challenge, a new class of gelatin methacryloyl (GelMA) GHS comprising porous microgels, fabricated via thermally induced polymer phase separation within composite microgels, is developed. These novel GHS not only attain hierarchical porosity across inter‐ and intramicrogel length scales, but also have up to ≈ 170% increase in void fraction compared with the nonporous microgel‐based GHS counterpart. Such increase in void fraction while maintaining structural stability, to the best of our knowledge, is among the highest increase reported in the literature. Compared with nonporous microgels in which cells cannot readily infiltrate, in vitro cell infiltration is significantly higher in the porous microgels. Furthermore, in vitro cell distribution in the GHS comprising porous microgels is more uniform compared with the GHS made up of nonporous microgels. In vivo subcutaneous implantation in mice shows that the GHS comprising porous microgels undergo higher and more uniform cell infiltration. Up to ≈ 78% increase in cell infiltration into GHS is yielded in vivo using the GHS fabricated from porous microgels. This work lays the foundation of engineering GelMA GHS with hierarchical porosity, superior cell infiltration, and enhanced tissue integration, which may open new opportunities for developing next‐generation granular biomaterials for accelerating tissue repair.
Journals
2025 EN
Conquest Oliver J. · Contractor Steefan · Weston Leigh
+1 more
Abstract First principles investigations are performed to study the effect of in‐plane strain and application of an electric field on the spin state energetics of cobalt doped ferroelectric perovskites, BaTiO 3 (BTO) and PbTiO 3 (PTO). The variation of strain has a large and systematic effect on the unit cell volume, and the spin splitting is clearly correlated with the volume, where increased volume favors the HS state. At equilibrium geometry, the local density approximation (LDA) favors the LS state, while the generalized‐gradient approximation (GGA) favors the HS state. However, when using the experimental lattice parameters, the GGA also favors the LS. The more accurate HSE and r 2 SCAN functionals both favor the HS state, but for BTO, on application of a small in‐plane compressive uniaxial strain of 2–3%, both the HS and LS states become degenerate in energy thus exhibiting bistable magnetism. Investigation of the magnetic anisotropy (including spin‐orbit coupling) shows a change in the (001) to (010) direction of the spin easy axis from the tetragonal to orthorhombic structural phases of Co:PTO/Co:BTO. The application of an external electric field on a Co:PTO slab has a small effect on the magnetic and structural properties of the system.
Journals
2025 EN
Olaniyan Ibukun · Albert Jürgen · Canabarro Beatriz
+7 more
Abstract The miniaturization of ferroelectrics with lateral size reduction is crucial for technological advancement but requires an understanding of the fundamental behavior of ferroelectrics at the nanoscale. While much attention has been focused on vertical scaling of perovskite ferroelectrics with thickness reduction, lateral scaling remains less explored. In this study, ferroelectricity is investigated in 20 nm thick single‐crystalline BaTiO 3 nanodisks with a diameter ranging from ≈ 400 down to 100 nm. They are fabricated by Ne ion milling of a 20 nm BaTiO 3 film epitaxially grown on SrTiO 3 ‐buffered silicon. The nanodisks are ferroelectric with a Curie temperature in the range 230–270 °C as determined by temperature‐dependent piezoresponse force microscopy. In 100 nm‐diameter nanodisks, the vertical polarization component adopts three distinct patterns in the pristine state, aligning with theoretical predictions. The most prevalent pattern features a uniformly up‐oriented vertical component. The rotational invariance of these domain patterns in the plane suggests a combination of center‐type and flux‐closure domains. Additionally, the up polarization can be switched progressively to down polarization upon application of a pulsed bias of increasing time width. The control of the polarization in nanostructures and of their progressive switching is of particular interest for memory applications.
Journals
2025 EN
Kedzierski Alexander · Kheirabadi Sina · Jaberi Arian
+7 more
Hydrogel Scaffolds In article number 2417704, Amir Sheikhi and co‐workers develop a new class of granular hydrogel scaffolds with hierarchical porosity by fabricating and covalently assembling gelatin methacryloyl (GelMA) porous microgels. These scaffolds feature a significantly higher void fraction compared with those made from nonporous microgels, thereby enhancing cell recruitment and tissue integration. This research may pave the way for developing hierarchically porous translational granular biomaterials, aiming to accelerate endogenous tissue repair.
Journals
2025 EN
Olaniyan Ibukun · Albert Jürgen · Canabarro Beatriz
+7 more
Single‐Crystalline BaTiO 3 Nanodisks The design features SEM images showing single‐crystalline ferroelectric BaTiO 3 nanodisks with diameters ranging from ∼400 to 100 nm patterned on a silicon substrate. More details can be found in the Research Article by Ibukun Olaniyan, Catherine Dubourdieu, and co‐workers ( 10.1002/adfm.202507905)
Journals
2025 EN
Koushik Tejas M. · Miller Catherine M. · Antunes Elsa
Abstract Porous scaffolds in bone tissue engineering (BTE) play a crucial role in facilitating osteointegration with host tissues and providing nutrients to cells involved in bone healing. Scaffold architecture influences osteointegration, biofunctionality and mechanical strength, necessitating a clear understanding of its impact. In this study, hydroxyapatite scaffolds are 3D printed with three types of triply periodic minimal surface (TPMS) structures: gyroid, lidinoid, and split‐P, at porosities ranging from 50% to 80%. Split‐P architecture exhibits the highest compression strength, between 15 and 25 MPa, but provides the least surface area for bone apatite precipitation. Conversely, gyroid and lidinoid structures demonstrate the highest levels of bone apatite precipitation across all porosities when immersed in simulated body fluid. To optimise scaffold design, graded structures were designed with multiple TPMS structures arranged in a core‐shell configuration. A structure featuring a solid core and a 70% gyroid shell achieves the highest compression strength of 120 MPa, while also supporting cell attachment and differentiation comparable to that of a fully porous structure. This combination of compression strength similar to cancellous bone and ability for positive interaction with osteoblast cells makes it an ideal candidate for load‐bearing applications in BTE.
Journals
2025 EN
Wang Qinglin · Achour Jihana · Emam Laila
+12 more
Abstract This study investigates the potential of pulmonary delivery of siRNA as an emergency therapy for acute lung injury (ALI). To obtain a quick anti‐inflammatory response, TNF‐α, a critical pro‐inflammatory cytokine, is knocked down for its early involvement in inflammatory responses. Therefore, TNF‐α siRNA‐lipid nanoparticles (LNPs) are designed and characterized for cellular uptake in lipopolysaccharide (LPS)‐activated RAW264.7 murine macrophages, primary alveolar macrophages, and neutrophils from a murine ALI model. Intracellular trafficking and siRNA cytoplasmic release are evaluated in untreated and LPS‐activated RAW264.7 cells. LPS‐activated cells exhibit a fast and strong uptake of LNPs, including in primary cells. In RAW264.7 cells, significant endosomal escape and siRNA cytoplasmic release are observed after 16 h. In vit ro efficacy studies reveal consistent TNF‐α inhibition across pre‐, co‐, and post‐incubation protocols, confirming the versatility of siRNA‐LNPs in preventive or curative conditions. After intratracheal administration of TNF‐α siRNA‐LNPs in a murine ALI model, the distribution of LNPs demonstrates an accumulation in immune cells, including macrophages and neutrophils, reducing TNF‐α and IL‐6 levels, indicating a rapid anti‐inflammatory effect. This work underscores the efficacy of TNF‐α siRNA‐LNPs in treating lung inflammatory diseases like ALI and highlights the importance of optimizing LNP distribution and delivery timing to enhance therapeutic outcomes.
Journals
2025 EN
Zhang Leifeng · Raza Muhammad Hamid · Wu Rong
+4 more
Abstract Interfaces in heterostructures play a major role in the functionality of electronic devices. Phenomena such as charge trapping/detrapping at interfaces under electric field affect the dynamics of metal/oxide/metal capacitors and metal/oxide/semiconductor transistors used for memory and logic applications. Charge traps are also key for the stabilization of a ferroelectric polarization and its ability to switch in ferroelectric devices such as ferroelectric tunnel junctions (FTJs). However, electric‐field induced charging phenomena remain unclear even in conventional dielectric heterostructures due to a lack of direct measurement methods. Here, it is shown how operando off‐axis electron holography can be used to quantify the charges trapped at the dielectric/dielectric interfaces as well as metal/dielectric interfaces in HfO 2 ‐ and Al 2 O 3 ‐based nanocapacitors. By mapping the electrostatic potential at sub‐nanometer spatial resolution while applying a bias, it is demonstrated that these interfaces present a high density of trapped charges, which strongly influence the electric field distribution within the device. The unprecedented sensitivity of the electron holography experiments coupled with numerical simulations highlights for the first time the linear relationship between the trapped charges at each interface and the applied bias, and the effect of the trapped charges on the local electrical behavior.
Journals
2025 EN
Li Gui · Gurzęda Bartosz · Iakunkov Artem
+5 more
Abstract Graphite oxides (GO) swell in liquid alcohols with significant expansion of c‐lattice. However, temperature‐dependent swelling of Hummers GO (HGO) has so far been reported only for methanol and ethanol. Here, HGO swelling in liquid 1‐alchohols (C1 to C22 according to the number of carbons) is studied as a function of temperature using in situ synchrotron radiation XRD. Swelling transitions never previously observed for HGO in any kind of polar solvents are found, enthalpy of these transition and compositions of HGO‐Cx solid solvates near the point of solvent melting reported. Swelling transitions from low temperature to high‐temperature phase are found for HGO in C10–C22 alcohols, similarly to earlier reported transitions in Brodie graphite oxide (BGO). The transitions correspond to a strong change of inter‐layer distance correlating with the alcohol molecules length and change in molecules orientation from perpendicular to parallel to GO planes (Type II transitions). However, Type I swelling transitions (related to insertion/removal of one layer of alcohol molecules) reported earlier for BGO are not found in HGO. Continuous changes of the d(001) spacing are revealed for HGO immersed in all smaller alcohols in the range C1 (methanol) to C9 (nonanol).
Journals
2025 EN
Caron Baptiste · Maresca Marc · Leroux Amélie
+4 more
Abstract Catheter‐associated infections are a major concern in hospitals, leading to both life‐threatening for the patients and a high cost for society. The development of a straightforward and industrial route to make an antibacterial catheter is thus worthwhile. This study demonstrates that the use of 2 wt.% of an antibacterial MeI‐quaternized poly(butyl methacrylate–block– N,N ‐dimetylaminoethyl methacrylate) P(BMA‐ b ‐DMAEMA) copolymer in combination with 2 wt.% of an antiadhesive poly(butyl methacrylate– block –poly(ethylene glycol) methyl ether methacrylate) P(BMA‐ b ‐PEG x MA) copolymer (with x the molecular weight of the PEG) as additives during the extrusion of the polyurethane matrix is an efficient method to produce antibacterial and antiadhesive PU materials without loss of activity after exposure to biologic media. The addition in the formulation of the antiadhesive copolymers enables protecting the surface from passivation and then to keep the contact possible between the bacteria and the antibacterial material. The antibacterial activity of the materials against E. coli and S. aureus is then preserved even after exposure to albumin, plasma, intralipids, or gastric acids. The prepared biomaterials also present no toxicity and are able to limit E. coli biofilm formation. Based on these results, this methodology can be realistically envisioned to elaborate long‐lasting venous or enteral catheters.